US Housing and the Passive Home Standard

Earlier this week we had a post on Passive Solar by Will Stewart. Today we have another post on Passive Solar Houses by TOD poster, Majorian, giving an overview of how much energy can be saved by building passive solar homes.



US Housing and the Passive House Standard

In 2000, almost 20 quads of primary energy, about 20% of US total energy consumption, was used for US residences. This is approximately the same amount of raw energy as was produced by all US coal mines in that year. About 1/3 of the 20 quads used is US residential construction came from coal via electricity.

In 2000, 60% of all US households lived in single family detached houses, serving almost 70 million households. By contrast, 20 million households (17%) lived in apartment buildings of 5 or more units and 10.5 million (10%) lived in apartment buildings of 2-4 units. The remainder were located in townhouses (single family attached) and mobile homes. At the 2005 peak the industry was producing over 2 million units per year.

These facts suggest that regardless of falling home prices and wages, the need for housing continues to grow. It is also apparent that the age of the housing stock is growing particularly in urban areas; as much as half of the housing stock in a typical city is over 40 years old. Older buildings can be more than 33% less energy efficient than a new buildings of the same size.

How can we make up the shortfall?

People could rent rooms assuming there aren’t zoning conflicts. More multifamily apartment buildings can be built though these are restricted by zoning ordinances as well. There’s also the fact that people prefer single unit housing over apartment living. Therefore the amount of new single family housing units is certain to grow in the near future.

There is also Stuart's hypothesis that people will tend to live in larger families, reversing the move from people living alone or in small nuclear families to more extended family co-habitation.

How can we significantly reduce our energy demand of our housing per unit?

We can significantly reduce our energy demand per housing unit by raising the energy standards, by building more apartment buildings and by phasing out old inefficient units. An Energy Star certified home would reduce energy consumption by 15% over a conventional home.

A LEED certified home would reduce consumption significantly depending on the level of LEED certification and the points that the builder chooses to focus on. There are several levels of LEED certification, and the credits can be applied across any number of areas (energy consumption, water reuse, materials resources, etc.).

A DOE ‘zero-energy’ home would reduce consumption by 70%.

Can we do better?

The Passive House Standard home is +90% more efficient than a new conventional home, without relying on PV solar arrays and passive solar space heating.

What is the Passive House Standard?

In 1988, Dr. Wolfgang Feist and Professor Bo Adamson began developing the concept of a building so tight and well-insulated that a building heating system would not be required. The result was the world’s first Passive House prototype. The house was built at Darmstadt Kranichstein in Germany in 1990, and was designed to meet a specific standard of 15 kwh (kilowatt-hours) per m2 (meter squared) per year for heating; 15 kwh per m2 per year for cooling; 120 kwh per m2 per year for the overall consumption of primary energy; and air tightness to 0.6 air changes per hour. The overall consumption requirement ties residential energy consumption directly to the issues of carbon footprint and Peak Oil. The Standard conforms to the goals of the Swiss 2000 Watt Society. There is also a Passive House Standard for multifamily housing.

This represents a 90% reduction in energy consumption over a new conventional house; a 1600 square foot house could be heated by a 1500 watt hair dryer!

The idea is to reduce energy consumption as much as possible before incorporating solar technologies such as photovoltaics or solar heating. The exception is for solar panel domestic hot water heating because in such a well insulated house this becomes the greatest heat demand, and it needs to be reduced to meet the 120 kwh per m2 per year restriction on energy use.

The first step is to correctly design the residence to meet the Standard, and that can be a real challenge depending on the local climate. It is one thing to build a Passive House in Oakland, California and quite another to build one in Duluth, Minnesota or Orlando, Florida. All the thermal bridges in the building design must be found and minimized, exterior insulation must be made continuous, and the whole envelope must be made practically airtight. The foundation can be particularly difficult to insulate.

These buildings typically are geometrically compact to minimize the surface to volume ratio. Balconies are independently supported to reduce cantilevers which compromise the thermal envelope. Basements are either eliminated or serve as unheated storage only.

The various high efficiency appliances must be carefully selected as they will be a source of potential overheating and will exceed the primary energy requirement of the Standard.

The Passive House consultant will do a takeoff from the building plans and input the appropriate data into the Passive House Planning Package (PHPP) to find out whether or not the design conforms to the Standard. Typically, this may be done a number of times before the building design actually passes.

You may be surprised to find out that these houses are generally no more expensive to build than conventional houses. The major hurdle is finding a contractor who is capable of building these precision designed structures and who can obtain the Passive House certified elements, particularly the super-insulated windows, the super-efficient ventilator, and high efficiency solar water heating panels. Once completed, before it becomes a certified Passive House, the house must undergo thermal image inspection and a blower door test to verify the construction.

Passive House is a European standard and the Europeans live in significantly smaller homes, use fewer gadgets, use less hot water, have less ‘stuff’, etc., so owning a Passive House is definitely a lifestyle statement and demonstrates a commitment to energy conservation. Certainly well-off individuals have built large houses to the Standard, but the idea of putting a large cooking hood or a sauna inside a Passive House would violate the principle and would almost certainly cause the house to fail the certification process.

In Europe, a Passive House represents a level of superior comfort. The quiet interior environment features warm walls, fresh air, no drafts, reduced levels of dust and a surprising amount of natural light. Over 10,000 Passive House Standard buildings have been constructed as of 2007.

Why should you choose a certified Passive House over other standards?

Passive House is a measure specifically designed to minimize overall energy use and to minimize the building’s carbon footprint. The designation also serves as a guarantee of low future building energy costs assuming the building is not modified after being certified.

[Editor's note: What's a better marketing term than "Passive" for extremely low energy input housing?]

Great article. Just to clarify a couple points, if you will. When you say 120 kwh per m2 per year for the overall consumption of primary energy can you confirm for me what is meant by primary energy? If, for example, my home is supplied with fossil-fired electricity and the utility's average heat rate is 10,000 BTUs/kWh, does that mean the allowance at the meter is 30 kWh/m2? Alternatively, if it's 120 kWh/m2 at the mast, then I suspect a good number of fairly conventional homes would have little difficulty meeting this target. I live in a cold climate (colder than Buffalo, NY) and my home's total energy use falls well below this upper threshold and although extensively upgraded in terms of its thermal efficiency, I can't imagine it would be anywhere near Passive House standards (very little passive solar gain, an un-insulated concrete slab floor and significantly higher air leakage).

Secondly, with regards to air tightness, I take it the 0.6 ACH standard is measured at 50 Pascal?

Cheers,
Paul

Paul,

Perhaps this may help answer your question;

Passivhaus Basic Principles
* the total energy demand for space heating and cooling is less than 15 kWh/m2/yr treated floor area;
* the total primary energy use for all appliances, domestic hot water and space heating and cooling is less than 120 kWh/m2/yr

Thanks, Will. I had suspected this was the case, but it could be easily interpreted to mean something quite different.

Obviously, the relative size of the home, local climate and the number and age of its occupants would skew the results rather dramatically (I shudder to think of the effect of four shower-loving, laundry-generating teenagers) but, last year, our two person household used a combined total of 72 kWh/m2 and, this year, with the addition of the second heat pump, that number should fall closer to 60 kWh/m2. It wouldn't be too difficult to improve on this. For about $2,000.00 CDN, I could replace my older unit with a model that is 1.5 times more energy efficient and conceivably get that number down to perhaps 50 or 55 kWh/m2; likewise, a solar DHW pre-heater or heat pump water heater and a drainwater heat-recovery system might further reduce that to 40 or 45 kWh/m2 (doing laundry with cold water would help too). Unless there's something I've missed, 120 kWh/m2/yr seems downright generous.

Cheers,
Paul

How does this post, which leads off with a picture of a house that over 90% of the population of the planet could not afford, and in fact if you include the current economic crisis it might be more like 99% of the population can't afford, benefit any one?

It's like calling everyone together on the titanic into the Grand Ballroom and discussing ship building . Jesus H. Krisip!

I've got an idea for a subject of discussion for TOD;

What if we could BUILD a just and equatible world to live in? WWWWoOooooooooooo!

Sorry, I guess I am just being stupid. AAAAAAAAhhhhh, Build better Mc Mansions, yeah, that’s what I meant to say.

I am sorry but I truely don't get it. Please explain to me how this relates to the current problems facing mankind in any sort of relivant way. Other than someone planning on building their dream house.

Well said. I am currently going through the growing pains of trying to live in a house that is supposed to be a passive solar with an in floor radiant heating system as a back up, and a wood stove to back that up. I did the design and take all the credit for the success or failure of what I am building. I have been using a lot of salvaged materials. We are by the way the only species on the planet that has someone else build our homes for us. Well it is a very steep learning curve and I am very glad that I have enough friends that have come to the rescue! wood I spent the day today cutting wood we have had 4 weeks of -20 to -40 degrees celcius and the home is not yet finished but it has been trying. The thrying includes a frozen septic tank. What an amazing learning curve this has been, I'm sure that I will be better prepared next winter than this, and likely better the one following.

cheers mike

Hang in there Mike is gets better. I built mine 30 years ago and I'm still fine tuning. Quite a few mistakes, nothing that hurt the structural integrity. There is no feeling to compare with sitting warm and toasty while it howls outside, knowing you built it. Putting you hand on the brick chimney you built and feeling the stored BTUs. I'm at about 7 degrees, and it's close to 75 inside. Snow again later tonite.

The wood thing does cease being work and becomes more like meditation. I actually prefer to split when it's very cold, when the wood is frozen it just explodes apart. Chop wood, carry water.

Don in Maine

I've been hand-splitting some ~30" dia. cottonwood logs (cut just a month or two ago) lately.  The maul bounces off them until they finally crack.  The same wood unfrozen will require the maul to be wrenched free fairly often.

A frozen SEPTIC TANK? My mind, having spent all it's life, except for vacations, in the southern US, boggles.

Hi souperman2,

I'm not sure I can properly answer your question, but I fully appreciate your point. It's an impressive looking home and without knowing the price tag, I can honestly say well beyond my price range.

FWIW, I prefer simple, cost-effective solutions and would much rather we repair and rehabilitate our existing housing stock than simply tear it down and build anew. I happen to live in a city where a good number of buildings are over two hundred years old (nothing out of the ordinary with respect to Europe and other parts of the world, but a bit of a rarity on this side of the pond) and they very much define the character and spirit of our community (e.g., see: http://en.wikipedia.org/wiki/Halifax_Town_Clock and http://www.pbase.com/halifaxphoto/downtown_halifax&page=1).

More to the point, when you renovate a home, you can start small and take things one step at a time, doing only as much as you can comfortably afford. For example, I upgraded my loft insulation from R6 to R60 in one afternoon -- no special tools or skills required and I re-cooped my initial investment in a few short months. Those 3M window kits, foam gaskets and all that caulking and weather stripping? Ditto - ditto. Two key points to keep in mind: One, if you continue to reinvest those savings in additional upgrades, these enhancements become largely self-financing. Two, you don't need to spend a lot of money to achieve large savings -- your first $100.00 will always save you more than the last $100.00.

BTW, thanks for keeping the conversation grounded -- we need to keep things real.

Cheers,
Paul

Often, the most cost effective energy improvements are replacing old HVAC systems with modern high efficiency units.

I am all for easy upgrades like Energy Star replacement windows, extra insulation in attics and even foam insulation in uninsulated exterior walls. However, if a home is old enough to not have insulation, in most cases it is more economical to build a new house. Fixing an old house is like restoring an old car. You will spend a lot of money and not make it new.

Most of my career was spent designing large manufacturing facilities. At various times we would have modernization programs and install new equipment in old facilities, thinking we were saving money by taking advantage of existing boilers, rail facilities, electrical substations, boilers, steam turbines, etc. So we might spend $300 million on an old plant instead of building a new plant for $750 million. What typically happened was that we found out that our cost estimates overlooked or underestimated something or and this resulted in a major cost overrun.

Invariably, the new facilities proved more profitable because everything was state of the art and had lower operating costs. Typically the old, rebuilt facilities ran another decade or so and were shut down. The new plants stayed competitive and will last many more decades.

Housing shares a lot of similarities.

Hi Paul,

In the commercial and industrial sectors where facilities are more finely tailored to the specific needs of each business, and where the choice of alternative sites is more limited and relocation to a new facility is considerably more complicated and costly, I see your point, but I'm not so sure the same can be said of our homes. The residential real estate market is much larger and more fluid, and there's a far greater range of product to chose from; consequently, if your needs or personal circumstances change (e.g., a divorce/separation, birth of a new child, kids move out, etc.) it can be easily exchanged for another. In any event, tearing down an existing structure and rebuilding from scratch involves a large commitment of capital, all of which must be secured upfront, whereas improving the thermal efficiency of a home can be accomplished over an extended period of time, as and when funds permit -- for a good and growing number of us, there's really no other option. In addition, some of us simply prefer older homes to new construction, for a variety of reasons, not withstanding their various deficiencies.

Secondly, although upgraded homes may never achieve the same level of technical performance, as you start to narrow the gap, it becomes pretty much a moot issue. I use this same argument when comparing air and ground source heat pumps -- it doesn't really matter if a ground source heat pump is twice as efficient as its air source counterpart if the home heating costs of one is $50.00/year and the other is $100.00. At some point, good does become good-enough. Along the same lines, if I can't afford to replace my old, leaky windows with new, high performance, low-e/argon units, a couple of inexpensive 3M window kits might very well do the trick -- my heating costs may be a little higher, but it's affordable and it could free up funds that could be better spent on other efficiency improvements that will generate a much higher return at the margin.

Cheers,
Paul

"FWIW, I prefer simple, cost-effective solutions and would much rather we repair and rehabilitate our existing housing stock than simply tear it down and build anew."

Hear, hear!

That is the post in this series I am waiting for. I hope I'm not disappointed.

lilith

yes that was my reaction to the photo in the article as well,(out of my price range), though I did like the "non-lawn" in the picture.

you might find some of the houses being built to the Passive House standard by e-co lab less like Mc Mansions
http://www.e-colab.org/ecolab/Projects.html
I understand they are working with a modular home manufacture to develop a more affordable package.

I think somewhere around 30% of our energy use is for homes, this obviously won't solve all the worlds problems, but I would argue that when we build new houses they should meet (or be much closer to ) the passive house standard, since the premium isn't that high, pay back would rather quick.

while my preferences lean toward organic agriculture in our current system natural gas is also used to make nitrogen fertilizer then on to food,feed, and even E-85 fuel. So their prices are dependent on each other.

How does this post, which leads off with a picture of a house that over 90% of the population of the planet could not afford, and in fact if you include the current economic crisis it might be more like 99% of the population can't afford, benefit any one?

a)The author did not provide a photo with his/her article, so I lifted the image off of the internets. You are likely right re affordability.

b)regarding 'benefitting anyone', please feel free to submit your own ideas on what/when/where/how we should proceed going forward - this series will only be as good as reader submissions/content.

Nate,

How about once in a while TOD just posts a TOPIC for discussion on Campfire, and let every one post on what they are doing about that topic.

Like say...preserving meat, or curing meat or butchering it.

The general topic would be about how to handle meat when the grocery store on longer works.

Chickens might be another good topic.

Hand tools another.

The list can grow but if its just refined to a particuliar subject then much good information can be exchanged by those who have ideas and plans that actually work ,in the dirt, so to speak.

When an ag agent comes to a meeting and espouses a new idea many will ask him "Yeah but how does it work in the dirt?" meaning lab research is fine but does it really work?

For instance two years ago an ag prof told me and another few that the ideas being put forth about so much nitrogen and chemicals was way overrated. He said we are using way way too many chemical/nutrient inputs.

Airdale

souperman2,

This article kinda fits with Will's solar passive articles and "builds our foundation of knowledge".

I have already started planning big time on doing what I can with my existing urban mini-house based upon Will's first article. This article adds a bit of detail to my thinking.

Our family will make significant reductions in energy use and consequent reduction of carbon footprint from practical application of the information in these articles. My garden won't die from heat exhaustion next summer either.

Majorian, thank you for your addition to my knowledge base.

Primary energy is fossil fuel or nuclear energy, not electricity which is figured from the grid. It's 120 kwh/m2 of space within the envelope per year for all heating, cooling domestic water and appliances. So for a American size 2000 square foot home-185 sq. meters-you are talking about in rough numbers
22.3 Mwh per year (the equivalent of about 14 boe/yr). The average US household uses 11 Mwh per of electricity
which is ~33 Mwh of primary energy plus another 11 Mwh of natural gas or +44 Mwh per year: 44000 kwh/185=237 kwh/m2 per year(graph shows 270 kwh/m2/yr).

It is actually more difficult to meet the Passive House standard for primary energy than for space heating,cooling(15 kwh/m2/yr). In a Passive House, domestic hot water is the greatest user of energy.

It's also interesting that the standard does not favor electrical use over fossil fuels because it honestly looks at reducing primary energy.

Your climate in Buffalo is considered very challenging compared to Germany. The solar passive features work only if you have a south facing exposure so things are even worse. If you look at a situation having your south winds blocked
in January by your neighbors you may find that your walls will 'grow' from 16" thick to 24" thick. In other words passive solar space heating helps a great deal but is not absolutely necessary to meet the standard.

Without analysing your house, I'd say that it probably can't be retrofit as a passivehouse short of a complete rebuild.
In Europe basements are unheated and outside the building enverlope. Heat loss thru the ground is critical.

An air tightness of .6 airchanges per hour is actually quite difficult to honestly achieve. You need to careful maintain the continuous air barrier around the interior. Verification is by a blowerdoor test with thermographic camera. 50 Pascals = 0.2 inches of water column or 1 PSF. A 20 mph wind produces 1 PSF at ground level. Of course for a Passive House, a mechanical ventilator provides code required fresh air of 0.35 air changes per hour, not infiltration.

Thanks for clarifying this, majorian; your explanation is more inline with my understanding of the meaning of this term, however, it does raise an interesting point. If my home were located in Manitoba, British Columbia, Québec or Newfoundland and Labrador, where electricity is predominately hydro-electric, I would be in far more enviable position than if I resided in, say, Alberta or Nova Scotia, which are heavily dependent upon thermal generation. That seems a little unfair.

With respect to air tightness, I had an energy audit performed on my home a few years ago as my renovations were underway, and the blower door test indicated that my air leakage at that time was 4.8 ACH @ 50 Pascals. I was disappointed with the results and I've since tightened things up further, but I won't really know how much things have improved until I'm re-tested.

For those who have a better technical appreciation of this than I, the results were presented to me as follows:



Cheers,
Paul

This is in UK - windy, often wet, temperate, cool temperature winter and summer, with brief occasional serious cold (very rarely colder than -10degC or '18 below' F).
I intend to replace part of a building with a 'superinsulated' box, designed also to achieve some modest spring / fall solar capture to help heat the adjoining structure. (The latter has a high heat-mass. The new building will also help gain control of air-ventilation of the old stone building.)
I intend a load-bearing woodframe 'box, with walls cast round the frame, using a 'hemp-lime' mix that will provide a warm-wall envelope with good air-tightnes round all windows etc, in addition to a very long-life wood preserving environment. A fairly light-weight mix of the fiber and the binding lime can be hand cast in sections that rapidly set into a self supporting wall. The wood plywood board that 'shutters' the cast, is removed within the hour and used for the next section. On an industrial scale, the wet mix can alternatively be blown on to a backing material. The whole must be protected from serious water penetration, but the hygroscopic properties of the surfaces has advantages of both 'feel' and dealing with occasional higher air-moisture levels inside the structure. Inner and outer surfaces are finished in suitable 'lime' render.
I understand the hemp/lime technology is adapted in modern form from traditional techniques from France.

Quibble - Serious cold, to those of us who have experienced it, would indeed be in the neighborhood of 18 below F, as you say. However, that equates to -28 C, as zero F is already itself -18 C. The -10 C temps you occasionally have to deal with is 14 F above, cold, but not seriously so by North American standards.

Looking at the Passive House design, I think one should understand that the design is not strictly based on passive solar collection. The fan and duct work for the energy recovery vent system depends on preconditioning the incoming air with a heat exchanger under the floor in the basement. That portion of the system creates a large thermal mass which stores warmth from the hot summer months and releases it during the cold winter months, which then allows the inlet air during the summer to be cooled. Also, the fans distribute the air from the warmer south side of the building to the colder rooms on the north side, thus the result is not a strictly passive system.

In your previous post regarding solar heat gain, you did not delve into the problem of the large heat loss during the night thru the glass. On cold nights, this loss can be very large, unless the windows are covered with enough insulation to minimize the loss. Movable curtains do not provide much insulation, especially as air can easily leak around the edges. Movable shutters or other closures with good R-value must be closed and opened daily, which makes the system less than "passive". Of course, these window coverings could be automated, but then the system would obviously be an "active" one. There are simple solar systems, similar to the "window box" designs or south wall air collectors which are truly passive but do not provide the wide view of the outside which those of us in the country love (at least, until the neighbors move in)...

I lived with a crude passive system (a sun porch) for about 20 years and found it to be too cold on colder days and too hot on mild sunny days. Building a solar system is not as simple as adding lots of glass facing the Equator. I worked on a solar design project with other students back in '74 and our efforts were turned into a "do it yourself" book on renewable energy. What you have presented is very similar to what we found back then or other works such as Bruce Anderson's "The Solar Home Book". I think we've gone beyond that level, perhaps to designs such as that of the "Passive house". But, each area requires a different combination of features as one size does not fit every climate. Perhaps you might extend your comments to cover the differences in regional implementations of solar so that newbies don't just start pounding nails before running the calculations.

E. Swanson

Looking at the Passive House design, I think one should understand that the design is not strictly based on passive solar collection.

I used to have similar complaints about some designs if they had even a hint of anything active in them. I've since sought in designs that provided as simple a design as possible, though recognize that some situations call for features that may not be considered strictly passive by some.

In your previous post regarding solar heat gain, you did not delve into the problem of the large heat loss during the night thru the glass.

The previous post did mention this in the section on windows;

So a balance must be struck by the designer/architect between the amount of energy received during winter sunlight hours vs. the amount of energy lost 24 hours a day.

... and future articles in the series delve into this deeper.

each area requires a different combination of features as one size does not fit every climate. Perhaps you might extend your comments to cover the differences in regional implementations of solar so that newbies don't just start pounding nails before running the calculations.

Agree, but please note there will be several articles in this series; the basics have just started to be covered (which will last for two more articles).

I agree that there has to be more attention paid to active parts of a 'High-Functioning House'.. (playing with the naming challenge.. )

It sometimes seems that there is an insistence that the house does it all for us, and with the 'Passive' title, also that the design does it all for the house.. kind of an entitlement mentality that is endemic in a lot of our 'Energy Slave' culture. I am not trying to put the PassivHaus movement down, but to mention that there are still unexamined assumptions that we might expose and readjust..

I have been very pleased with the Insulated Curtains we use, while they are not enough by a long shot. Even a simple modification like magnets or velcro around the sides and bottom would drastically improve the thermo-cyling that can accomany many homemade 'Window Quilts'. I just tuck ours in as tight as I and gravity can keep them there.. But they also have an active control system that, in our case is validated with a couple diplomas, bachelor's and masters degrees. Why settle for investing in quirky AI, when you've already got I-times-3 built into the house-envelope? Why, because people think that a 'higher quality of lifestyle' means not having to open shutters and curtains like some 'maid' every day. I think class and slave history still infects so many seemingly neutral aspects of our lives today. (I look at all the 'Royalty' games kids play, Kings and Princesses.. and say to myself, where can I be inserting story-forms and Archetypes that give kids some other options for their games and ultimately their worldview that doesn't lean so constantly on 'Noblesse-Oblige', Divine Rights, Dynasty and Feudalism? It's innocuous and has massive momentum, and is really very rarely being pushed in other directions..)

I'm not against some automated systems as well, but have to remind myself that 'chopping wood and carrying water' is part of being alive, and can keep you in closer daily contact with your surroundings, providing a few necessary rituals that are reasonable ways to tend your nest.

'Before reaching enlightenment, the pupil Chops wood and Carries water. Upon finding enlightenment, the Sage Chops wood, and Carries water.'

'I don't want to live in a castle, I don't want to live in a castle, too many chilly rooms.'
(Hmm.. I think it was 'Empty Rooms', but I'll let you choose.)
- Cat Stevens, I wanna live in an Igloo

Passive houses have that name because they need the absolute minimum of active elements. They have to be carefully insulated, but otherwise are extremely simple. The basic Passive house has no heating system and just a ventilation system with a single small fan for the whole house. I agree that there is pleasure in 'chopping wood and carrying water', but there pleasures could be redirected e.g. into gardening.

Thanks. I do appreciate why it is named as it is.. I don't mean to suggest that all or even most people involved in them are being lazy or self-indulgent.. in my experience it's usually nothing of the sort. I even really appreciate the kinds of design which do take care of things slowly and quietly, taking advantage of the natural flows around them.

That said, there are still attitudes even in the Alt-Energy crowd (I was confronted with one last night, hence the reaction, I suppose) that say "Our houses should produce all the energy we need and more. There is plenty of energy for us. There is no need to cut back or reduce, or for spartan austerity" .. which while technically supportable is tied to a lot of spoiled, 'I don't have to work, tech will do all the work' kind of attitudes that also have a fondness for many things 'Passive'.. (passive regressive?)

As much as I've enjoyed gathering and splitting wood in the past (no wood heaters in this home ), I would certainly only build a house and a masonry stove in it that would reduce to the minimum just how much chopping was required of us. (if any) .. I used the term to imply being actively involved in a physical life, to which gardening is surely a part. Today, for example, I'm continuing to Chop Wood with the crosscut saw, assembling my second Hot Air Solar Collector.

Best,
Bob

I would like to point out, as I did previously on the solar design topic, that efficiency absent renewable construction is a bit of 1 step forward, one step back looking at the long term.

To what degree, if any, does the passivhaus movement look to or consider renewable construction?

Cheers

Great question..

I don't know what aspects you would include for something to be renewable.. whether it 'can be renewed', or is made from renewed (pre-owned, recycled) building materials. An aspect that I come up against constantly is how to build a part of a house so that it can be efficiently upgraded or replaced when the time comes. I tend to build with Screws, not nails, since I will reuse a piece of wood forever, if I can just strip it down when it's done one job.. reuse the screws too, of course.

A dumpster full of nail-laden 2x4 scrap and such-like is a sad testament, IMO.

Are the windows installed so they can be replaced without excessive waste being created? Without walls or trim being trashed in the process (Screws make that process easier..) The Roofing Material.. will there be Asphalt and nails in a dumpster, heading for a landfill in a decade or two, or can you feed the worn roofing into a new supply stream for 'downcycling' as doghouse and shed roofs... or being added to the cans and bottles on tuesday night (so to speak)

A favorite pet peeve is how many electrical junctions and wiring are so unreusable. Well you can, but retwisting and bending ends into a utility box, using tons of PVC tape to package it up.. As with medical equipment, I know that there is a constant refrain of fire safety, etc.., and yet there is a middleground.. there are neater ways to wire multi-input boxes without creating a rats nest that will have to be dumpstered if you need to reconfigure things, buying more replacement parts and cabling as you go..

I didn't want to stretch the issue too far. I'm asking only about basic construction. As an example, I'd bet a cob and/or rammed earth home would be near passivhaus standard based on the fact you are talking about massive, solid walls. There is no roofing standard that I am aware of, so there's likely loss there. I assume it would be plumb easy to seal that up tightly, particularly since so many natural homes also use earthen rooves, too. Leaves just the joining to seal up.

Note also my post in the previous article thread with the examples at Dancing Rabbit EcoVillage and their use of renewable or recycled - and local - materials.

Cheers

After thinking about this for a moment, it sounds like the basis for a campfire article. Would you consider submitting an article proposal on this subject?

I'm not qualified to do it (zero engineering and or energy production/consumption knowledge/experience), and I think you've just demonstrated that the proposal is effectively made.

:)

Here's my proposal:

An investigation of:

- calculations of efficiency over time sans considerations of renewability vs. building to meet both criteria
- an investigation/comparison of existing designs/methods in terms of renewability and efficiency
- Preliminary exploration of integrated designs
- economic considerations in terms of accessibility of design/ability to construct across economic levels. That is, if only relatively wealthy - middle class Americans, e.g. - people can achieve these design goals, are we in essence just greenwashing?
- The development of a rubric to help individuals identify which design considerations best suit their situation

I would limit the discussion to currently available, proven designs so affordability is clearly established.

Regarding integrated design: My dream house would involve natural building with passive solar, integrating an envelope (I really like the brick-based air circulation idea as an alternative to a basement or crawl space) while seeking maximum efficiency, BUT balanced with using renewable/recycled and locally available resources. The basic structural design should also be buildable by virtually anyone, experienced or not. At most, a workshop should suffice for training. (Passivhaus likely would not meet this requirement.)

Cheers

"My dream house would involve natural building with passive solar, integrating an envelope (I really like the brick-based air circulation idea as an alternative to a basement or crawl space) while seeking maximum efficiency, BUT balanced with using renewable/recycled and locally available resources."
Considering the current trends in housing, this is really only going to work with the folk that cruise the landscape and collect the detrius of the wastefull building practices that currently "conform to the local building codes" wherever they may be.

Mike,

This is why location is so important for me. I really hope my final choice can be unimproved land with trees so I have the choice of using as many materials as possible from my own land for the basic structure. If I go straw bale, well, that'll most likely come from a neighbor - unless I get a hay field in the bargain! Electrical, plumbing, doors, etc., will have to come from the economy, preferably second-hand.

Who knows where things will end up. Gotta get visas first. But, if I can have chili peppers and tomatoes growing on my balcony in Korea in January, maybe anything is possible.

NOTE!!! For those who have made comments eschewing thermal mass: don't tell my plants! They are on a balcony facing SSW that doesn't get sun till noon, that is sealed from the outside elements with nothing more than weather stripping on one half and plastic sheeting on the other, has @ 6.5 X 2.75M of sliding glass doors, and is in a building that is 19 stories high (11th fl.) and all concrete. Temps on the balcony, in freezing weather, have been between 8C and 24C. Never below 8C.

Cheers

In talking about the Passive Home concept, it seems to be better to either use the German term PassivHaus, or better still "Factor-10" or "Near Net Zero", illustrating a 90% reduction in energy from a conventional home, or using a mere 10% of what a conventional home uses.

Many people get confused by the name and think that everything in it is passive, including ventilation, when a Passive House always includes a mechanical ventilation system because the building envelope is built very tight.

Oh, and the photo that accompanies the article is not a Passive House. It's a straw bale home in Ontario with excessive glazing. The solar heat gain is far less than the heat lost at night. Energy efficiency has been sacrificed in the name of daylight and views. It's not a good example of passive solar design.

I'm puzzled by the assumption that multi-unit building are more efficient, both by Stuart and in this Post.

Overall statistics show that, on average, multi-unit buildings use the same heating and cooling per sq ft as single family houses. This is likely due primarily to the fact that heat loss and gain are much more affected by windows than by outside wall exposure, and apartments and condo's maximize the outside exposure and window area for all rooms.

I've had this discussion with Alan Drake, and he has agreed. In fact, he simply advocates smaller square footage per person.

It seems to me that good design, like the PassiveHaus methods, are the important thing, rather than moving to multi-unit buildings or smaller living space.

Overall statistics show that, on average, multi-unit buildings use the same heating and cooling per sq ft as single family houses.

Nick, could you supply the links to your statistics? I realize that some apartments don't charge separately for energy (just including it in the rent), so to be fair, a comparison with units that do charge for energy would make the most valid comparison. Also note that apartments have fewer windows per wall area.

Smaller footprints, combined with smart building design, can work in tandem to reduce the energy dependence of the building sector. After all;

(Building Heat Loss in BTU's per hour) =
(Building Total Surface Area in sq.ft.) / (Surface Area "R" value) x (Temperature Difference)

I agree, it sounds like a classic example of statistics without worrying about methodology, or Mark Twain's "There are three kinds of lies: lies, damned lies, and statistics". As you wrote, it is intrinsically easier and cheaper to insulate multi-unit buildings. There was a documentary a few years back on German TV on a conversion of a large apartment block to something close to the Passivhaus standard if not the Standard itself, but it probably started out more efficient than a typical house.

Of course, multi-unit buildings also lead to much greater efficiency in transportation as well, not to mention reduced use of construction materials.

See my post below. We see that multi-unit buildings are much less efficient, on average.

"Nick, could you supply the links to your statistics?"

Sure, but it may take a little while. This was a US gov website, looking at energy, not costs.

"apartments have fewer windows per wall area"

Generally apartments & condo's have more windows than single families, as a % of outside wall area. How many urban high rise apt/condo's have floor to ceiling, wall to wall windows? Think glass boxes. Even mid-rise or low-rise apts maximize windows, compared to single families.

"Smaller footprints"

No question, less sq ft means less energy, all else being equal. But, that's not efficiency, that's conservation: choosing to live with less.

"combined with smart building design"

That's what I'm saying: design is by far most important.

"(Building Heat Loss in BTU's per hour) =
(Building Total Surface Area in sq.ft.) / (Surface Area "R" value) x (Temperature Difference)"

Yes, but windows have a much, much lower R value, so they dominate the calculation. Think how much difference having an open door or window makes: it doesn't matter what the wall R value is, if you have a hole in the wall. Well, windows are pretty close to that, R value-wise.

Generally apartments & condo's have more windows than single families, as a % of outside wall area.

But apartments have a far lower percentage of outside wall and ceiling per unit floor area (most have only 1 outside wall), so again one has to look at the total heat loss of the living quarters; a % of window space is interesting statistic but not the driving factor. And apartments in my area are by no means mostly windowed exterior, but are close to the same window/wall ratios of local houses (noting that construction in the last two decades here has incorporated much more window space in houses than those of a generation or more ago).

Still curious to see your links claiming apartments took as much energy to heat/cool as single family homes.

Here we go:

Residential Energy Consumption Survey
http://www.eia.doe.gov/emeu/recs/contents.html

2005 Residential Energy Consumption Survey--Detailed Tables
http://www.eia.doe.gov/emeu/recs/recs2005/hc2005_tables/c&e/detailed_tab...

Average Consumption, British Thermal Units (Btu) per Household (US9)
http://www.eia.doe.gov/emeu/recs/recs2005/hc2005_tables/c&e/pdf/tableus9...

Housing Unit Characteristics and Energy Usage Indicators (US1:Part 1)
http://www.eia.doe.gov/emeu/recs/recs2005/hc2005_tables/c&e/pdf/tableus9...

Total BTU's
Type of Housing Unit
Single-Family Detached. 108.3
Single-Family Attached 91.7
Apartments in 2-4 Unit Buildings 84.5
Apartments in 5 or More Unit Buildings 53.8

Floorspace/
Household (sqft)
Type of Housing Unit
Single-Family Detached. 2,720
Single-Family Attached 1,941
Apartments in 2-4 Unit Buildings 1,090
Apartments in 5 or More Unit Buildings 872

BTU's/ thousand SF
Type of Housing Unit
Single-Family Detached. 39.816
Single-Family Attached 47.244
Apartments in 2-4 Unit Buildings 77.523
Apartments in 5 or More Unit Buildings 61.697

We see that Single-Family Detached are most efficient, followed by Single-Family Attached (townhouses), then Apartments in 5 or More Unit Buildings, and at the bottom are Apartments in 2-4 Unit Buildings!

We see that apartments manage to use somewhat less energy by being much, much smaller on average.

Why is this?

Here's something somewhat on point:
http://www.eia.doe.gov/emeu/reps/enduse/er01_mid-atl.html

"Typically, an older housing unit will consume more energy for space heating than a newer housing unit. (Although newer homes tend to be larger than older homes, their average energy use per square foot is lower.)

We can guess that much multi-unit housing is much older, and has the old problem of a landlord/tenant split in responsibility. Probably it's much less efficient by design (single pane windows with R value of .04, very low wall insulation, old furnaces, etc). Newer multi-unit housing units, of course, have much larger windows.

We can guess that much multi-unit housing is much older, and has the old problem of a landlord/tenant split in responsibility. Probably it's much less efficient by design (single pane windows with R value of .04, very low wall insulation, old furnaces, etc).

These two factors alone skew the results, plus I'm willing to bet that more of the apartment building units are in cooler climes, which would skew the results even more.

What you did present, even with the above factors, is that apartments use less energy than single family homes. However, you disparaged apartments because they did have as expansive a floor plan as single family homes. With such a "more is better!" high discount rate, I'll direct your attention to one of Nate's previous articles.

I don't see anything you presented that demonstrates that a new single family home will be more efficient that a multi-unit apartment with the same levels of insulation, weatherization, and HVAC efficiency.

Your argument almost sounds like "since SUVs are as efficient on a per pound basis, it's a good idea to buy one", and instead of reducing our energy dependence, we increase it.

Unless you are of the persuasion that we shouldn't start using less energy...

"These two factors alone skew the results"

"Skew isn't the right word: that suggests the results are incorrect. No, they explain the results.

"I'm willing to bet that more of the apartment building units are in cooler climes"

Well, first, what makes you think that? 2nd, it could be, but then they'd have less A/C (these stats include everything), so I'm not sure the difference would be enormous. 3rd, do you have any stats that let us know that it would make a big difference? Enough to overcome the fact that overall single family homes use half as much energy per square foot as small apt buildings, and 2/3 as much as large apt buildings?

"What you did present, even with the above factors, is that apartments use less energy than single family homes. "

Sure, barely. But that's not what we were discussing. We were discussing per sq ft efficiency. OK, how about a different measure of efficiency: energy per person? Different housing types have a different number of occupants: single family homes use less energy per person than townhomes or 2-4 unit apt buildings, and only slightly more than apts.

"such a "more is better!" high discount rate"

That's not what I said. What I said was: energy-related design is much more important than building type. We can have small single families or large ones, and so on.

"I don't see anything you presented that demonstrates that a new single family home will be more efficient that a multi-unit apartment with the same levels of insulation, weatherization, and HVAC efficiency."

True. Again, what I said was: energy-related design is much more important than building type. Either building type can be made to be efficient.

"Your argument almost sounds like "since SUVs are as efficient on a per pound basis, it's a good idea to buy one", and instead of reducing our energy dependence, we increase it."

1) Again, what I said was: energy-related design is much more important than building type. Efficient single family homes are available, plug-in SUV's aren't.

2) SUV's and homes are different in another way: homes last 10-20x as long, and we build about 6% as many per year (625K homes per year vs 10M light vehicles). We scrap old SUV's, but we rarely demolish old homes. Even during the white flight of the 50's & 60's, the houses from which people fled weren't abandoned - someone else moved in. If the middle class were to flee the suburbs, the same thing would happen, except the new occupants would have much less money for energy efficiency.

3)Choosing a more efficient vehicle is trivial, while moving homes is a very expensive proposition. Urban condos can be more expensive than suburban homes, even while they're half the sq ft. It's much, much cheaper to make an existing home energy efficient than to move.

4) Again, different housing types have a different number of occupants: single family homes use less energy per person than townhomes or 2-4 unit apt buildings, and only slightly more than apts. SUV's, on the other hand, don't.

5) SUV's have other problems: they're make the roads much more dangerous, while not improving the safety of their occupants.

6) OTOH, it's true for SUV's as well that design is more important. A plug-in SUV really wouldn't be a big environmental problem (windpower is very cheap to build, should we choose: a one-time payment of $1,500 would pay for the wind capacity needed to power even a very big SUV forever).

The fact is, housing is currently overbuilt. We have more homes than we need, and we're not going to be building a whole lot for a while. We need to primarily pay attention to retrofits.

Finally, what I said was: energy-related design is much more important than building type. This is true both for existing units, and newly built: conventionally designed existing multi-units aren't more efficient (in fact, they're less), and new single families can be made just as efficient or more.

Urban condos can be more expensive than suburban homes, even while they're half the sq ft. It's much, much cheaper to make an existing home energy efficient than to move. I don't know why people waste a lot of thought on very expensive, painful, slow solutions like moving people into different housing, when much cheaper and faster solutions are available.

Either building type can be made to be efficient.

If you build an apartment building with units having, say, 1800 sq ft with the same techniques as you build a single family home, any of the apartment units are going to consume less energy than the single family home. Even with a Passivhaus approach. You simply can't escape the physics.

Your other point seems to revolve around moving people out of single family homes into apartments in urban areas. I don't think anyone is suggesting that, though many people are having to abandon the homes due to mortgage default.

Hi Will,

I haven't looked at this all that closely but, as you can appreciate, apartments and condominiums that are individually metered and for which the tenant pays their own heat and hot water use significantly less energy than those that are bulk metered and for which these services are provided at no additional charge -- perhaps in the order of 15 to 25% (e.g., http://www.marketwire.com/press-release/Stratacon-Inc-593630.html). Unmetered consumption can also vary widely by tenant, and it's generally believed that 30 per cent of residents will be responsible for 50 per cent of a building's overall energy requirements.

In addition, there are several common elements that must be taken into consideration. For example, the lighting in hall corridors, stairwells, lobby and other public areas will likely operate twenty-fours hours a day, as will the elevator(s) if the building is so equipped. If there's underground parking, this garage area will be continuously illuminated and perhaps heated during the winter months. There may be any number of ventilation fans that also run 24/7 and even ice melting cables embedded in the sidewalks and parking ramps to keep them free of ice and snow. Most of us would be positively shocked if we were to view the billing records of some of these buildings -- I can tell you I've nearly fallen out of my chair on more than one occasion.

Cheers,
Paul

"If you build an apartment building with units having, say, 1800 sq ft with the same techniques as you build a single family home, any of the apartment units are going to consume less energy than the single family home. "

Not really - that's too simplistic.

1st, the physics also works against you. You can't put all of the windows on the south side; in a large building you can't use solar for water or PV (some Passive House designs go to net zero energy with solar, which couldn't be done with an apt bldg); you won't have space for ground-based heat pumps (which likely means wasteful resistance heating, or fossil fuels, though air-based heat pumps will be useful in some cases); after a certain point A/C is working mainly to move internally generated heat, not external heat, so no further savings are possible; using earthen berms (or any large inexpensive structural element) for heat buffers will tend to be impossible.

2nd, The Passive House standard sets a maximum, which an architect will design against, so energy consumption will be the same. In particular, exterior windows will be maximized until they hit the limit.

3rd, even if you did manage to reduce further with apts, the absolute difference is going to be so small as to not matter. The Passive House standard is about 3 KWH/SF for heating and cooling, so a 1,800 SF single family will use only 5,400 KWH. If an apt saves 20% beyond that, that's only 960 KWH, or about $100. That could be supplied cleanly by about a onetime expenditure of $700 for wind turbines. For $100 savings we're going to go with apts over another form of housing??

"moving people out of single family homes into apartments in urban areas. I don't think anyone is suggesting that"

I'm glad that doesn't seem mainstream. Certainly a few people are, like Alan Drake, and Kunstler.

"many people are having to abandon the homes due to mortgage default."

In the long run, not many of those homes will stay vacant.

I have seen solar water heaters in apartment buildings, all on the southerly side. Just a little plumbing required.

I have seen higher % windows on some McMansions than any Apartment building ever. It was "the style" for a while. Bay windows, large picture windows, etc. Dual 5 ton a/c.

Preserving the current Suburban form has LOTS of "hidden" energy costs. And most of it is low quality, built for just a few decades. And oversized for the future market. The few new SFRs are dropping in size (Drumbeat a few days ago; down about 200 sq ft from Peak Square Feet).

In the long run, not many of those homes will stay vacant.

It will be "interesting to see" what happens to homes and subdivisions that go vacant, repairs are not made, major cuts in municipal services and schools, etc.

My brother married two years ago, his wife had a home in Mesa (suburb of Phoenix) that they put on the market then. One "shark" low ball offer over a year ago (I advised "take it"). Not even one potential buyer has looked at the house in ten months (perhaps some drive bys).

I have not been there, but I understand that the sub-division is just filled with "for sale" signs, many now getting weathered. Unfortunately not close to new Light Rail line that goes about 1 mile into Mesa.

My brother is worried that it may need some paint soon to stay "presentable". Meanwhile electric bills come in every month, as do tax bills and mortgage notes.

Alan

"I have seen solar water heaters in apartment buildings"

I'd love to see a picture - do you happen remember the address? Was it all of the units on that wall, or a scattering?

"all on the southerly side. "

I would assume that this is something available only to one, possibly two out of the four walls of the building?

"Just a little plumbing required."

That sounds like more than just a little bit of plumbing: it's unlikely that the water heater was on the outside wall...

"I have seen higher % windows on some McMansions than any Apartment building ever."

I can imagine. OTOH, how do you beat the 100% (floor to ceiling, dividing wall to dividing wall) that some Mies van der Rohe type glass-box high rises reach?

"Preserving the current Suburban form has LOTS of "hidden" energy costs. "

Boy, have we had this conversation before. I've said many times that this exaggerates the tiny % of energy overhead caused by spread-out development. There was a TOD article (Huntington Beach, CA?) that gave numbers - they were very low. Can you quantify this idea?

"most of it is low quality, built for just a few decades"

On this, too, I've asked you for details. Is it foundation? Siding? Roofing? Electrical or plumbing?

"oversized for the future market. "

Well, certainly for the near future, which won't help their prices.

"It will be "interesting to see" what happens to homes and subdivisions that go vacant, repairs are not made, major cuts in municipal services and schools, etc."

There is certainly an excess of housing, and some of that is vacant - it would be interesting to know exactly how much - anyone have stats?. That's true for highrises in Las Vegas, Miami and elsewhere, and even more so for some newly built exurbs which were sold to subprime borrowers. Some of that excess will be abandoned and demolished, but most, in the longterm, will become cheap enough to be afforded by, and inhabited by somebody.

I have three charts related to home supply. One shows that the homes for sale as a percent of U.S. population in a long term uptrend. Low point of 0.2% from 1969 to1973. Average is 0.49% from 1965 to date. High is 1%, which occurred after a dramatic rise from the average starting in 2003. Percent of vacant homes shows a similar trend, low 1.0% (1968-1979), Average 1.5%, high at current time 2.8%.

I will post a link if I find the source.

You are correct that overbuilding occurred in FL, CA, AZ, NV.

As for McMansions being of low quality, I have to agree. They are not inferior to other conventional construction, but they are certainly no match for houses I've seen/built. See the publication "Concrete Homes".

Conventional houses are too expensive to maintain.
My long time home in suburban Atlanta was close to being a McMansion. Beautiful home built in 1985. By the time I sold it in 2006, I had done $50,000 in repairs and upgrades, not counting my labor. Polybutyelene pipe replacement, flexible HVAC duct replacement with metal, new asphalt shingle roof, new carpet, new HVAC, water heater, dishwasher, gutters, replaced rotted balcony and decks, termites, paint, etc. Upgraded to double pane windows, but that is typical code for new construction. Buyers seldom consider these expenses. Also, on the Gulf Coast where I live now, the insurance is very high.

My new house was designed to avoid as many of these expenses as possible. I chose concrete with an aluminum roof. No exterior painting. Low insurance. No possibility of termites, rot, mold. No need to evacuate for hurricanes. Last year I paid $1200 for all electricity and natural gas.

Sad thing is that home buyers paid huge mark up to builders and developers. Buyers and real estate people looked at comparable sales and not replacement costs. I saw people in my former neighborhood hood in Atlanta pay $850,000 for a new house I could have built for $650,000. That would have been a nice paycheck for an owner builder for 9 months work, especially since it would have been tax free! The markup is now gone, and the retail buyer is underwater the $200,000 difference.

Thanks. So, the vacancy rate has increased by a large % relatively, but by an absolute amount only by 1.3%, to a level that is well below the average apartment vacancy rate. Interesting.

"As for McMansions being of low quality, I have to agree. They are not inferior to other conventional construction, but they are certainly no match for houses I've seen/built. "

Ok, so you're saying they're just as good as anything else (including urban construction), but that we can do better. Sounds good.

"Conventional houses are too expensive to maintain."

I agree, though I'm not sure about the appearance of concrete and metal - they seem a bit harsh.

"Sad thing is that home buyers paid huge mark up to builders and developers. "

Yeah.

As for the appearance of concrete homes, they cannot be distinguished from conventional without close inspection. They are usually have a stucco finish, but can have brick or stone veneer.

There there is the old European stone look:
http://homepage.mac.com/gaudel/HTMLSITE/house/index.html
http://www.dac-art.net/

Dac art is the high end of concrete. I saw two of these homes in nearby Gulf Shores, AL. The blocks have Styrofoam insulation and are pre finished interior and exterior.

AAC is somewhat more expensive than conventional construction. The difference is less in hurricane areas becsuse of reinforcement required by code. AAC is plastered on the interior, stucco exterior, in pleasent pastel colors.. Alternately you can drywall the interior.

Standing seam roofing comes in a variety of colors. It's widely used along the Gulf Coast.

What do you think of steel framing for residential?

The negative about steel framing is that it coducts more heat than wood, and steel houses have been shown to be less energy efficient. There may be some special designs for exterior insulation cladding or staggered studs to cut down on heat transfer.

Anything fireproof and termite proof is a big plus in my opinion.

I wouldn't hesitate to use it on interior walls.

There are Passiv- apartment buildings, schools, office buildings etc. in Germany and Austria. One in Germany --I am not sure it is certified passivhaus-- uses wood pellets for supplemental heating and hot water. I don't think apartment buildings have higher % windows, you need to take into account that one or two sides of an apartment often will have no windows at all.

Like it or not, in an energy constrained world, apartments make a lot more sense than suburban homes.

B, please read all of the dialog with Will - I think it will answer a lot of questions.

"There are Passiv- apartment buildings"

Sure - both single family and apts can be energy efficient.

" I don't think apartment buildings have higher % windows, you need to take into account that one or two sides of an apartment often will have no windows at all."

They do as a % of outside wall space.

"Like it or not, in an energy constrained world, apartments make a lot more sense than suburban homes."

No. Existing Suburban homes use less energy per sq ft than existing apts - again, please see the preceding discussion. They can be retrofitted to low energy consumption at a cost that is lower than moving to the city. New suburban homes can reduce energy consumption to a point that is as low is desired. They can do net-zero consumption, if desired. If you want small, they can be small. And, they'll be much cheaper than urban apts or condos.

Bio wrote;
"Like it or not, in an energy constrained world, apartments make a lot more sense than suburban homes."

Nick wrote;
No. Existing Suburban homes use less energy per sq ft than existing apts

Nick, you're going have to face the fact that few people on TOD will think more sprawl and higher energy consumption makes sense in a energy-declining world.

"Nick, you're going have to face the fact that few people on TOD will think more sprawl and higher energy consumption makes sense in a energy-declining world."

I'm not suggesting higher energy consumption. I am saying that 1) "sprawl" and energy consumption aren't linked in the way that is common wisdom on TOD, and 2) "sprawl" is a red herring - energy related design, like Passive House, is what's important.

I agree - this is a hard sell on TOD. Nevertheless, it's true.

Nevertheless, it's true.

Not sure what the difference is between 1) and 2), but let's just say we have a different set of perspectives and leave it at that.

Oh, there's not a big difference. I'm just trying different ways to communicate, I suppose.

"let's just say we have a different set of perspectives"

Well, I'm still curious as to how they're different - I suspect we'd find that it's partly a matter of how info is presented. In particular, I hate the form of presentation that suggests that we're in deep trouble if we continue to underfund rail and transit oriented development, or that suburbia and single family homes (in which most people live) are in deep trouble.

The fact is that there are affordable and straightforward solutions to our energy problems that don't require a complete reorganization of our lives.

Would a reorganization be good? Sure, but not for energy reasons - that's a distraction from the real reasons for doing things differently.

I have been extraordinarily busy in DC, but I am taking a moment before 7 AM.

Your perception of reality varies from mine. I see things you do not see, or refuse to see. Given this, discussing with you has a low return on a large effort. A bit like the color blind arguing with those that are not as to whether the the top and bottom lights on a stop light are different.

I see massive indirect energy waste to support Suburbia, mail & UPS delivery, water & sewer being pumped, massive acres of pavement to maintain, lawns to water & fertilize, etc. You do not.

I see oversized low quality homes with maximized surface area and excessive glazing in a certain % of Suburbia. You do not.

(BTW, you used a glass wall to show that apartments have too much glazing. One, such architecture is quite rare and two, some McMansions STILL have more glazing. One wall of 4 is glass vs. twice as many square ft of walls as needed for interior sq ft with >20% glazing on those walls).

You point to higher city construction costs but fail to realize why.

Suburban building codes have a long standing reputation for laxity (>low quality), the labor forces can be different ("undocumented workers" with On The Job training and will return home in a couple of years vs union labor with a multi-year apprenticeship and a lifetime of experience will simply cost more).

Building codes also apply to materials. Adhesives have a finite life time, OSB will not last forever. I look at PEX plumbing and remember polybutylene plumbing. I have seen concrete poured during a Phoenix summer, noted deterioration in Phoenix construction that was simply covered up, seen OSB supporting my brother's granite countertops, wiring that was borderline unsafe, etc. etc.

Quality (and land cost) is the primary driver for the delta in construction costs. I see it, you do not.

Shared walls save energy, I see this basic fact, you do not.

Given the difference in what we see, I see little reason for prolonged debates with you.

You see the world one way, I see a very different world. As with the color blind, little is to be gained debating the difference between the top and bottom lights on a stop light.

Alan

"Your perception of reality varies from mine. I see things you do not see, or refuse to see. Given this, discussing with you has a low return on a large effort. A bit like the color blind arguing with those that are not as to whether the the top and bottom lights on a stop light are different."

Alan, I'm very disappointed to hear this kind of ad hominem silliness from you. I've always responded to your ideas thoughtfully, with numbers and sources when needed. Many times we've had productive conversations, but I regret to say that we have gone around in circles many other times, not because I'm not able to see and understand your ideas, but because you haven't listened to mine, and provided specific, thoughtful responses that actually took my ideas into account and responded to them with numbers and sources as needed.

A dialogue won't go anywhere if either side doesn't really listen and respond thoughtfully.

"I see massive indirect energy waste to support Suburbia, mail & UPS delivery, water & sewer being pumped, massive acres of pavement to maintain, lawns to water & fertilize, etc."

I understand what you mean, but you've never provided numbers or data to back it up. First, most of these (mail & UPS delivery, water & sewer being pumped) are very small % wise (we saw that in the post by the mayor of Huntington Beach CA at http://local.theoildrum.com/node/4057#comments_top , search for the comment at May 27, 2008 - 3:26pm ); some are already electrified (water & sewer being pumped); can be electrified (mail & UPS delivery); have substitutes (acres of pavement). Lawns to water & fertilize are someting you haven't mentioned before. I'll have to think about that - my first thought is that they don't seem essential, and I don't think water shortages or high priced fertilizer are going to drive people out of suburbia.

"I see oversized low quality homes with maximized surface area and excessive glazing in a certain % of Suburbia. "

I see them (except perhaps for the "low quality" part - I'll talk about that later). I've never said I didn't. The question is, what does that mean? Are they going be completely abandoned because of energy costs? That's unrealistic: why wouldn't they improve the windows and insulation, and then get a heat pump? That's cheaper than moving, and a whole lot cheaper than demolition and replacement.

"you used a glass wall to show that apartments have too much glazing"

I never said they had too much glazing: I said they had more, as a % of their exterior wall surface, than a single family home. Surely that's clear.

"such architecture is quite rare "

?????? Not in newer construction, and especially not in high rises. The typical high rise built in the last 50 years is very close to a pure glass box.

"some McMansions STILL have more glazing"

Sure, as an absolute number. I would agree.

"One wall of 4 is glass vs. twice as many square ft of walls as needed for interior sq ft with >20% glazing on those walls)."

And you just proved my point: ">20% glazing" is a lot less than the % you'll see on high-rises, and substantially lower than the % on townhouses.

more detail later...

I did not say which of us was color-blind, but we do see different worlds. Thus the round and round.

Electricity used to pump water and sewer is still excessive energy wasted on an energy inefficient urban form.

What will happen, will happen. Future facts and developments will determine the future (although I unfortunately expect MASSIVE gov't subsidies to preserve Suburbia which will skew the results), not our debate such as it is.

why wouldn't they improve the windows and insulation, and then get a heat pump? That's a lot cheaper than moving.

Because they are under water on their mortgage and will chose to go bankrupt and move instead ? Roof and slab repairs have a higher priority on their limited spending ? Schools have gotten terrible and crime is rising ? The neighborhood is going downhill ? The "wrong people" moved in down the block ?

Pick any "white flight" reason you want from the 1960s as a reason not to invest in energy efficiency in their home.
----
if a McMansion has 200% more wall area/sq ft and 20% glazing, it has more glazing (per sq ft and much more relevant, per resident) than does a glass wall apartment/condo.

The "Lever Building" look (all glass, from late 1950s) has been passe' for a decade or two.

Alan

"I did not say which of us was color-blind, but we do see different worlds."

There's a difference between color-blindness and different perspectives. Differing perspectives can be brought together with communication.

"Electricity used to pump water and sewer is still excessive energy wasted on an energy inefficient urban form."

Perhaps, but why is it important? Is 5 KWH's per household per month (as a wild guess) important? It would require a onetime $100 investment in wind power to supply.

"What will happen, will happen."

You don't really feel that way, and neither do most people. We want to know what's coming, as best as possible, in part to plan for it.

"Because they are under water on their mortgage and will chose to go bankrupt and move instead ? "

A few will (assuming more than that means assuming that we're facing a really deep depression, something on which I suspect we could also have a long & difficult discussion due to the indirect nature of the evidence). The primary effect of the housing crash has been to reduce mobility. If they do move, it won't be primarily because of their energy bills, and the house will be bought by someone else.

"The "wrong people" moved in down the block ?"

I'm baffled by this. The "wrong people" aren't people? They'll live in the house, and use energy, just like the old.

"Pick any "white flight" reason you want from the 1960s "

White flight left behind homes which were, indeed, for the most part occupied. Yes, a small % of the whole was demolished: though concentrated in some places, it was relatively small.

"if a McMansion has 200% more wall area/sq ft and 20% glazing, it has more glazing "

Hmmm. 200% means 3x as much wall area. 3 times 20% is 60%. So, if the shared-wall unit (townhouse, condo or apt) has 60% wall covered by windows, then they're equal. Perhaps sometimes the SFH will have more but that example suggests that if so, it won't be by much.

Actually doing some calculations helps the dialogue make progress.

"much more relevant, per resident"

We partially agree - it's somewhat more, though single family homes have more people, on average, than townhouses or multi-units: see my previous links for the data.

"The "Lever Building" look (all glass, from late 1950s) has been passe' for a decade or two."

Perhaps the flat glass look has, but the % of exterior wall covered by glass is still very high - perhaps 75-80%? If you'd estimate less, what would you estimate? Not less than 50%, surely. And, of course, the slightly older buildings are still there...

I took a look jeffvail's series ( starting here: http://www.theoildrum.com/node/4720#more )on suburbia, just now. They lay out fairly well some of my arguments: suburbia is here to stay; and dealing with commuting post Peak is not a big deal (I noticed you raised the issue of dealing with total VMT - pretty much the same strategies apply (higher efficiency cars, delivery services, carpooling), except that it's worth noting that both urb and suburbanites have pretty much the same long-distance VMT).

Is 5 KWH's per household per month (as a wild guess) important?

We simply see the world in different ways.

I was shocked to learn that 20% of the electricity used in Phoenix went to pump & treat water and sewage. An extreme case admittedly.

Energy is necessary to move water through water distribution systems and to make it potable. In the Report Watergy by Alliance to Save Energy has been asserted that 2-3% of the world’s energy consumption is used to pump and treat water for civil and industrial supply.

Note agricultural water not included. Or sewage. Suburbia is a much larger than average user of water (lawns) and energy to pump each gallon to user and back as sewage.

ec.europa.eu/environment/water/quantity/pdf/2007_01_09_forum_meeting/emilia_romagna_water_energy.pdf

But I see the acres of pavement, miles of water & sewer lines, etc. etc. You do not.

This is more than a difference in perspectives, it is what we see or do not see.

Glass walled apartments (quite rare, office buildings are much more common) have one wall of four glass. A McMansion with twice the surface that a box would have, has >20% glass. That is MORE glass per sq ft than a glass walled apartment.

Alan

"I was shocked to learn that 20% of the electricity used in Phoenix went to pump & treat water and sewage. "

20% of all electricity in Phoenix? Surely you don't mean that - that's just not possible. "Phoenix Water Services’ annual operating budget is approximately $270 million " http://www.ci.phoenix.az.us/WATER/wtrfacts.html
population is 1,552,259 http://en.wikipedia.org/wiki/Phoenix,_Arizona
so less than $200/year for water costs. Probably less than $50/year is for electricity: that can't be 20% of overall power consumption.

more later...

Most of the energy went to pump water up hill on the Central Arizona Project.

http://www.cap-az.com/static/index.cfm?contentID=35
click to enlarge

Only in post-WW II America would a large city/sprawling suburb be located in such an impractical location.

By contrast, New York City potable water is gravity alone up to the 5th or 6th floor.

Plus sewage takes some energy as well. They treat waste water back to potable water standards.

Alan

Phoenix Water Services’ annual operating budget of approximately $270 million for 1.6M people is right in line with other big cities: Cook County (Chicago), for instance, spends $800M for 5M people.

"We simply see the world in different ways."

Yes, I'm afraid there may be truth to that: it begins to look like your dislike of suburbs in general, and Phoenix in particular, has clouded your judgement. I mean, think about it: we're talking about a cost of $160 per person, per year, a cost which is almost identical to that of a city like Chicago. It's a low cost, and it's not higher than a more traditional city. Where is the problem??

I took a look at the Central Arizona Project, BTW: it appears to have expenses of about $225M, of which about 70M is for power, and about 50% gets reimbursed from the water treatment budgets. So, it looks like there's an additional approximately $115M spread over 5M Arizona customers, or about $23/person/year. $2/month: that's not high overhead.

"Glass walled apartments (quite rare"

Rare? It would be interesting to see actual numbers - high rise condo's may not be a big % of all new multi-units, but they're likely to be a large % of new multi-units in big cities, which is what we're talking about, right? And, high rise condo's are all glass walled.

"A McMansion with twice the surface that a box would have, has >20% glass. That is MORE glass per sq ft than a glass walled apartment."

Well, it would be helpful to work out the math, but let's assume that's correct, and the SFH has more glass/SF than the condo/apt. Why is this such a big deal? Perhaps the SFH installs an air-source heat pump for $4k, and the larger society installs $8k of wind capacity, and the problem (at minimum, the increment over the multi-unit, and probably much more) is fixed for less than the cost of the realtor's commission to sell the place.

"By contrast, New York City potable water is gravity alone up to the 5th or 6th floor."

Wow. A quick look at the NYC DEP webpage confirmed that, but...I think that's unusual among city water supplies - I don't think it's really fair to compare that to Phoenix. I think it would also be fairer to compare the overall budget, not just power costs. NYC's overall water budget ( http://home2.nyc.gov/html/nycwaterboard/pdf/blue_book/bluebook_2009.pdf )is about $2.5B, serving 9M people, so that's $278/per person per year, or 74% more than Phoenix.

Do you know how the water gets up that gravity well in the first place? If it comes from rainfall in upper NY, they'd have maintain that pressure for 100's of miles - that suggests a lot of leakage. If it comes from the Hudson...well, the Hudson is well below the level of 1st floor apts in NYC, so how do they avoid pumping?

"Plus sewage takes some energy as well. They treat waste water back to potable water standards."

Wouldn't that power be required in all cities, dense or suburban-style?

AFAIK, New York City potable water is all gravity feed. Water Tunnel #3 allowed last wells to be mothballed.

http://nyc.gov/html/dep/html/drinking_water/wsmaps_wide.shtml

http://nyc.gov/html/dep/html/drinking_water/maplevels_wide.shtml

The 60 mile long New York City Water Tunnel #3 is nearing the end of Phases #1 & #2

http://www.water-technology.net/projects/new_york/

NYC is an extreme case in one direction, Phoenix in the other.

CAP Pumping Plants Need 2478050 MWh

www.westconnect.com/filestorage/HTP%20Presentation%2011-7-08.pdf

A constant 283 MW + transmission losses would do that. (The 20% figure came from local Phoenix media, CAP is a big slice but not the only one).

The rates are so cheap because of preferred access to Hoover Dam and other federal hydropower. Subsidy for sprawl. Rest from local strip mined coal.

Arizona uses very advanced sewage treatment (good enough for potable water), other areas use much less treatment (enough to eliminate feces borne diseases, major disruptions of biosystems, etc.). An energy delta between simple and advanced sewage treatment.

Modern water and sewage treatment installations (i.e. Suburbia) uses pumps much more to "solve problems". Minimize initial capital costs.

As with NYC Water Tunnels #1 and #2 (early 1900s) the older, pre-WW II design philosolphy was much more sustainable.

Dense cities require less pumping/gallon due to simply being closer together (larger pipes > less resistance, shorter distances). Suburbs need more water (lawns, pools, golf courses, car washing, etc.)/capita and the water (and sewage) are pumped further with more energy.

On my father's place in Georgetown KY they build a new sewage lift station to serve new suburbs. Two 200 hp pumps. Cheaper than drilling through a hill to get to expanded sewage treatment plant (located downhill from "Old Georgetown").

As for "glass walled" condos in big cities; my sister's co-op in Manhattan has less glass than my brother's Suburban homes, even adjusting for family size (1 vs. 5). I did not notice any other residential towers there that were all glass, just some 60s & 70s office buildings. Condo I am staying in in Baltimore (8th floor of 10) was glass on one side (one sliding glass door to balcony, rest "normal" glass areas). Given rooms with zero glass, overall fenestration is moderate and heating costs (22 F ATM with northerly exposure) seem reasonable. Heavy drapes (4) help.

Quite a contrast with Suburban homes.

And I am also talking about mid-sized cities and towns, not just "big cities". 500,000, 250,000 and even 100,000 population can, and should, get Urban Rail and energy efficient urban forms. College towns of 40,000 are also candidates.

One can correct for glass sides (I saw condo tower near Univ. of Texas get "reskinned") and other old errors of design more easily than upgrading Suburban direct and indirect energy costs. Individual metering would be a MAJOR step for energy efficiency for rental housing.

This has been a time consuming response and it will change nothing. You will not see the irreducible waste and poor quality (including social interactions) design of Suburbia.

As a child I observed and questioned "white flight" and the dynamics of urban form change. IT IS NOT "INDIVIDUAL LOGICAL CHOICES" as you suppose, but a herd dynamic. I see this, you do not.

Best Hopes for More Productive Discussions,

Alan

"This has been a time consuming response and it will change nothing."

Don't be discouraged - we'll get there.

"You will not see the irreducible waste and poor quality (including social interactions) design of Suburbia."

You haven't been listening. I agree that suburbia is a poor place to live. My point is: suburbia is a sunk cost (Jeffvail's phrasing), and it's not going away quickly; energy isn't suburbia's main problem; there are faster and higher $-ROI and E-ROI solutions to our energy problems than changing from SFH to multi-unit and from suburban to urban. That doesn't mean that rail and TOD aren't good things that should be promoted, both for quality of life and to help with resource problems.

We need solutions in the next few years, ones that provide a big % of our needs within 20 years. Electrification of light vehicles is the fastest and biggest single solution; replacement of long-haul freight trucking with rail, improved residential insulation (window & wall) together with electrification of HVAC are parallel but slightly less important; expansion of passenger rail and electrification of freight rail are very valuable, but behind the rest (as energy solutions). I don't mean this to be comprehensive, of course.

My original point here was that (for new construction) design, like Passive House, is much more important than SFH vs multi-unit, and urban vs suburban. Much cheaper as an energy solution. Retrofitting of existing stock, of course, is much more important than anything we do related to new construction.

"As a child I observed and questioned "white flight" and the dynamics of urban form change. IT IS NOT "INDIVIDUAL LOGICAL CHOICES" as you suppose, but a herd dynamic. I see this, you do not."

I never said that exactly. What I do point out is that land costs are indeed important. Inner city housing costs are 3-5x as much as exurban costs. NO appears to be an exception, but in traditional cities like NYC, Chicago, Boston, SF, housing (and food, to a lesser extent) costs are dramatically higher in the center, and gradually fall as you get farther out. Do you see that changing anytime soon? Really?

I'm not sure about construction quality. I'd note that there's a lot of non-union labor and low-quality in urban construction - I've seen it personally. I've seen sub-standard electrical, concrete, roofs, etc. I've also seen urban building codes that were designed to inflate costs and add excess union labor (e.g., requiring copper for wastepipes). So, I'm not sure that anecdotes of poor suburban construction are all that helpful.

I just have to shake my head when you suggest that suburban housing is going to be demolished in meaningful numbers and in a meaningful timeframe because of low quality - that just seems like hyperbole.

Thanks for the NYC water info - it's interesting.

I have to note again that NYC's costs are much higher than those of Phoenix. I note the power subsidy - it looks like CAP is paying about 2.5 cents/KWH, which is probably roughly half what other very large government users would pay. Still, that suggests a cost of about 70M, which is still below the differential between Phoenix and NYC, and only $14/person/year. New Orleans appears to pay about $183M for 500K customers, or about $366/person/year, or about double the costs for Phoenix.

"my sister's co-op in Manhattan has less glass "

How old is it? A lot of Manhattan co-ops date from before the glass-box trend. I think we're primarily debating about new construction here.

"I did not notice any other residential towers there that were all glass"

hmmm. I wonder how much high-rise residential construction there is in Manhattan these days. If there isn't much, that argues against the idea of moving people there.

"Condo I am staying in in Baltimore.. heating costs (22 F ATM with northerly exposure) seem reasonable"

I'm not suggesting that new condo heating costs/SF are higher, just that they're not that different from new SFH.

"mid-sized cities and towns...can, and should, get Urban Rail and energy efficient urban forms"

Sure.

"One can correct for glass sides (I saw condo tower near Univ. of Texas get "reskinned") and other old errors of design more easily than upgrading Suburban direct and indirect energy costs."

How much did the reskinning cost? $5/SF? How much energy did it save? $.25/SF/year? That doesn't sound especially cost-effective. Are you sure it was done for energy reasons, or just because the old facade needed repair?

"Individual metering would be a MAJOR step for energy efficiency for rental housing"

Sure - I believe someone else here cited 10-15%. Of course, that probably also need some supporting investment, and would only apply to a portion of all multi-unit homes. That wouldn't close much of the gap with SFH efficiency.

So. We agree on many things. I really think that we agree on more than you'd like to admit. I agree that rail is neglected, and is needed for many reasons. I just don't think it does it a service to exaggerate it's energy contributions.

We need solutions in the next few years, ones that provide a big % of our needs within 20 years.

1950-1970

"We" managed to trash almost EVERY prime commercial property (almost w/o exception) aka "downtowns" in two decades. Many well built, established neighborhoods were abandoned/ lowered population densities as well aka "inner cities".

We did it once in 20 years, without the major driving force of Peak Oil (one could argue that integration/migration of rural Southern African-Americans to cities was comparable). We can do it again in 20 years.

Once "Suburban Flight" becomes established, it will develop a force of it's own, as "White Flight" did before.

A high percentage of Phoenix water costs are energy, a factor likely to rise in value (if not cost) faster than any other factor.

Phoenix has not yet "aged" enough to start having to deal with infrastructure replacement yet. A temporary savings.

Alan

"1950-1970"

In 1950 we had an enormous backlog of needed construction - not much happened during the Depression, or WWII. Much of the construction was not replacement, much of the abandoned property was very poor deep rural (some Southern, as you note). Today we're coming off of a very big construction bubble, with excess property everywhere: suburban and city. Alan, you know this very well: you can't casually suggest this without dealing with this very, very big difference.

""We" managed to trash almost EVERY prime commercial property (almost w/o exception) aka "downtowns" in two decades. "

That's a bit of an exaggeration. It doesn't apply to NYC, Chicago, Boston, San Francisco. I would note that commercial property has a shorter life/higher turnover than residential.

"Many well built, established neighborhoods were abandoned/ lowered population densities as well aka "inner cities"."

Many? Could you provide data? As far as I can tell, most of these neighborhoods continued to be occupied by someone, white, African-American or other.

"We did it once in 20 years"

Did what? Replaced 50% of our metropolitan area residential units? I see no evidence of that: we added much housing, but we didn't lose a big % of the old. We're only building 625K units per year now - we'd have to get above 2.75M (a rate we've never reached at peak building rates), figure out how to finance them when residential construction is at the very bottom of anyone's lending list these days, in dense areas that require a great deal more planning and supporting infrastructure (including a lot of rail, most of which would take a decade itself for planning and construction). That's a breathtaking assertion.

"We can do it again in 20 years."

Even if we could, should we? As a wild guess, we have 110M units of residential space. To replace 50%, at a ridiculously conservative $100K each (assuming only 1,000 SF/unit, $100/SF, not including supporting rail or other infrastructure(!) and the demolition of the surplus housing), would cost $5.5B and only eliminate a fraction of our energy consumption (an optimistic estimate would be 50% - your estimate for 12 years out was only 6%). The same money (and sense of political urgency) could build enough wind power to replace all of our coal and gas generation, power all of our transportation and heat pumps for all of our homes, and eliminate 80% of our oil consumption and 90% of CO2.

"Once "Suburban Flight" becomes established, it will develop a force of it's own, as "White Flight" did before."

Flight to the suburbs had the wind of cheap, greenfield land at it's back. Flight to the city would have the very big headwind of much more expensive, complicated infill housing in front of it (even if all suburban building codes were made more expensive, or urban codes relaxed). It would also face enormous opposition from the existing residents, who wouldn't be eager to double the density of their neighborhoods and lose many of their homes. It would require the demolition of a lot of existing urban/near urban SFH's and low-rise housing, to be replaced on the same site by townhouses and medium and high rises - this would require local permissions that would be impossible without a WWII-like emergency and no other alternatives, when such alternatives are obviously available, faster and more energy and cost-effective.

"A high percentage of Phoenix water costs are energy, a factor likely to rise in value (if not cost) faster than any other factor."

It's not that important. If the CAP costs were to quadruple to 10 cents per KWH and $280M (pretty unlikely), it would only add $210M over 5M residents, or $42/year. That's not big, and would leave their costs much lower than NYC or NO.

"Phoenix has not yet "aged" enough to start having to deal with infrastructure replacement yet. A temporary savings."

Their budget includes some infrastructure costs. If they were to increase to be 50% of their overall budget (as is NYC's) it would still be less expensive than NYC, and much less than NO.

Alan, I've more or less said all this stuff before, and you haven't integrated it into your thinking. You haven't really dealt with it - you've just repeated these ideas. We won't make progress until you do...

That's a bit of an exaggeration. It doesn't apply to NYC, Chicago, Boston, San Francisco.

It does, as well as 500 mid-sized cities and smaller towns. Some downtowns "bounced" after hitting bottom post-1970, some didn't. Remember the bankruptcy of New York City in 1977 ?

Inner cities have almost uniformly lost population as US population has increased. Many of those homes are empty and boarded up (plenty in Baltimore, I have seen thousands of well built empty rowhouses here).

Evidence ? Check the US census (which shows a diluted effect, including more than "inner cities"). (I was a bit surprised that 1970 was not the nadir, 1970-1980 was pretty bad)

http://www.census.gov/population/www/documentation/twps0027/twps0027.html

30% of Americans WANT to move to TOD, certainly a good enough reason to builds LOTS of TOD. Subtract 25% from the population of Suburbia and I expect the rest to fail.

And we are currently "hard wired" for an epidemic of diabetes, focused on Suburbia. Suburbia is socially isolated and based on fear of the "other". Two good reasons to dismantle it, besides it's inherent energy inefficiency and poor quality construction.

You do not see the reality I see, I do NOT see the reality you see.

As I said earlier, a waste of time debating. I spent the time anyway out of respect for you, even knowing the end result.

Alan

"I spent the time anyway out of respect for you, even knowing the end result."

I appreciate the respect.

" waste of time debating"

But, you didn't really answer me. How can we make progess if you don't?

The information you gave in this comment (downtowns, census) might shade my statements slightly, but I knew already that these things happened - the question is, how much? For instance, we agree that some areas lost a lot of housing and population (I made a point of not listing Detroit, or Baltimore, for instance) and others lost some, but I would estimate that significantly more than 50% of that housing overall was swiftly occupied by new people.

We already agree that urbia is better than suburbia - lack of exercise, social isolation, etc.

But, what about the difference between the 1930-1945 housing drought and the current housing bubble?

What about the enormously greater E and $-ROI of electrification, vs mass movement from suburbia to TOD?

What about the difference in cost between urban and suburban housing, and how that makes it much more difficult for people to move from the suburbs to the urbs?

We won't make progress without discussing these things.

You think that ONLY SFRs are housing starts.

HOUSING COMPLETIONS
Privately-owned housing completions in November were at a seasonally adjusted annual rate of 1,084,000. This is 3.3 percent
(±9.5%)* above the revised October estimate of 1,049,000, but is 22.8 percent (±6.5%) below the revised November 2007 rate of
1,404,000.
Single-family housing completions in November were at a rate of 760,000; this is 0.9 percent (±10.2%)* above the October figure of
753,000. The November rate for units in buildings with five units or more was 301,000.

1,084,000 - 760,000 - 301,000 = only 43,000 units of duplexes, triplexes and fourplexes (my inference).

http://www.census.gov/const/www/newresconstindex.html

2 million units/year of adaptive re-use of existing structures and multi-family units plus 300,000/yr of SFRrs (<1/2 todays rate) plus slightly higher people/unit will do the job. Only slightly more resources than todays reduced rates (SFRs are DOWN to an average of around 2,350 sq ft).

One SFR of last year (2,5xx sq ft) uses as much material as a triplex (OK more refrigerators).

New Orleans, with low sq ft/unit and /capita, housed 40% of the population in 20% of the housing in 2006.

You underestimate the "adaptive reuse" of existing structures (commercial, industrial, residential) and rehabilitation. Minimal materials, mostly labor.

Alan

"You think that ONLY SFRs are housing starts."

Alan, that's jumping to personal assumptions again.

"HOUSING COMPLETIONS
Privately-owned housing completions in November were at a seasonally adjusted annual rate of 1,084,000. "

That completions. We're talking about starts.

"HOUSING STARTS
Privately-owned housing starts in November were at a seasonally adjusted annual rate of 625,000." see http://www.census.gov/const/newresconst.pdf

"You underestimate the "adaptive reuse" of existing structures (commercial, industrial, residential) and rehabilitation. Minimal materials, mostly labor."

I don't understand. Are you suggesting that there's 55-110 billion sq ft of unused existing structures??

I can only assume you mean urban dwellers doubling up, as you've described in the past (60% reduction in SF/person) But why would society, with it's current credit crunch problems caused by housing contraction, pursue demolition of suburbia and conversion of urban housing in this way?

Why would people want to do live this way?? Surely you don't think this is what people have in mind when they respond to a survey that asks whether they might be interested in living in TOD? We could house everyone very cheaply in vans, too, but why?

I've shown that suburban government's energy costs (both for transportation and for water/sewage) are minimal. Why not just electrify HVAC and transportation, using both light vehicles in the short run and rail in the long run?

Why would society want to demolish Suburbia ?

Because it is dysfunctional on multiple levels, ... and it is not "cool" anymore (NEVER forget the power of fads & herd movements).

Enough FWOs are going to move to tents anyway. Smaller urban homes will be attractive for many.

We have plenty of electricity

BS !!

21% to 22% of US electricity comes from natural gas, increased use will turn first towards that fuel, fast & cheap to build plants.

3% of electricity can come from increased conservation over a decade or two, 17% for EVs (plus heating loads) ? Not so likely.

#2 source will be more coal burned.

BTW, you underestimate the speed and scale with which we can build Urban Rail. We built subways in all of our larger cities and streetcars in over 500 cities and towns in just twenty years; 1897-1916.

We had 3% to 4% of today's GDP, PRIMITIVE technology, a third of the population, etc.

Alan

"Why would society want to demolish Suburbia ? Because it is dysfunctional on multiple levels"

Perhaps that's better phrased "Why would society choose to demolish Suburbia ?" It's not especially more dysfunctional now than it used to be. Except for energy, which can be more easily and quickly fixed in other ways.

"it is not "cool" anymore "

I see a little evidence of that. A few more young people in the city, a few more empty-nesters moving there. What evidence have you seen of anything more than a relatively small change? It has to be a really big change, for people to pay 2 or 3 times as much for housing.

"Smaller urban homes will be attractive for many."

Not to save money. You have to pay more for less. If people are moving to save money, they won't be going to the city.

"21% to 22% of US electricity comes from natural gas,"

Last I saw that was 19%.

"increased use will turn first towards that fuel, fast & cheap to build plants."

That's a choice. Are we talking about what's likely, or what would be desirable public policy? You have to know that a dramatic expansion of rail isn't likely - it's simply desirable public policy for which we're advocating.

"3% of electricity can come from increased conservation over a decade or two, 17% for EVs (plus heating loads) ? Not so likely."

Easy to do, if we choose. It's only another 1% per year, at a very reasonable cost of about $30B per year. Much, much cheaper than the oil it replaces. Makes environmental, social, and economic sense. Will we do it? I think it's probable - we're building more nameplate wind than coal right now, and wind plans are growing while coal plans are shrinking.

"#2 source will be more coal burned. "

Again, that's a choice. It's fairly likely that not that much more new coal will be built - it's very expensive (almost as expensive as wind, but with additional fuel costs), and opposition is mounting. OTOH, we may choose to build coal. If so, what are the chances we'll be making better choices on housing?

Finally, it doesn't matter. A coal-powered EV is at least as good as an oil-powered ICE for AGW.

" you underestimate the speed and scale with which we can build Urban Rail. We built subways in all of our larger cities and streetcars in over 500 cities and towns in just twenty years; 1897-1916."

Again, that's a choice. Lately, we've been moving mighty slowly on rail projects (in part due to a lot more social and environmental concerns than we used to have), a lot more slowly than the pace with which we currently do windfarms. We could speed up both, certainly.

One difference in our POVs. You appear (from your arguments & analysis) to assume that people en masse make logical, cost effective decisions.

If that was so, then there would never have been the SUV boom, Exurban McMansions, burnt orange shag carpeting or avocado colored appliances.

I see where small tipping points create large avalanches.

Building "T", supporting "OD", ending the numerous gov't supports for Suburbia will create "Suburban Flight". Meet the current market demand for TOD (30%) and all else will follow. Once the herd starts stampeding, it is very difficult to stop.

Alan

BTW, EVs are not energy efficient. Just moving people, not cargo, will take 17% of today's US electricity.

"You appear (from your arguments & analysis) to assume that people en masse make logical, cost effective decisions."

Well, no, I just think that they do part of the time. It seems to me that you're arguing that rising energy costs will impel people back to higher density TOD living, and I'm pointing out that makes no sense. Why would people leave a $200K 2,500 SF house, spend $20K in moving costs, and buy a $300K (or more) 1,200 SF condo, when they could instead spend $4K on a heat pump and $4K on a Prius? Why spend $120K instead of $8K?

"If that was so, then there would never have been the SUV boom, Exurban McMansions, burnt orange shag carpeting or avocado colored appliances."

No question. There's a story I like to tell about that: in Japan there was no tradition of engagement rings until the 70's when DeBeers started promoting diamond engagement rings - now they're mandatory.

"I see where small tipping points create large avalanches."

Avalanches go downhill. The move to the suburbs went downhill, towards cheaper land. A move backwards would have to go uphill: an exurban house (or condo or townhouse) can cost $75/SF; a medium distant unit might cost $150/SF; an inner city unit might cost $300, 400 and on up per SF.

Ask any realtor in a traditional city like Chicago, NYC, Boston about this. They'll tell you that there's a big cost difference between the city and the suburbs, and that if a buyer is interested in both the city and the suburbs then it's a waste of time to show them anything in the city, because it will be much more expensive for something comparable. They'll waste the realtor's time sightseeing in the city, and then go to the suburbs every time. They may like the idea of the city, but they're not willing to pay extra for it, so it's not going to happen.

Urban realtors consider buyers who are looking in both areas an enormous pain - some refuse to work with them.

"Building "T","

That will take a while. The first wave of projects you outline won't do it. It will take what, 15 to 30 years just to lay the groundwork for the OD to follow? That's fine, but it's slow.

"supporting "OD", ending the numerous gov't supports for Suburbia "

What do you have in mind? The mortgage deduction helps more in the city (deductions help higher income buyers, and there's a big deductible in the form of the standard deduction, so the mortgage deduction doesn't help low-priced properties at all). Local government does spend $ on roads - it would be interesting to see numbers. There are some new mortgage products that account for reduced commuting and energy costs (we may take advantage of them for a refi), but they won't begin to overcome a large home price differential. It would be good to run the numbers.

"Meet the current market demand for TOD (30%)"

Again, are they willing to pay extra for it?? People would say the same thing for hybrids - 70% in surveys are interested - but only 3% buy them because of a 15-20% cost difference. Please re-read my description of realtor experiences - it's the reality.

"EVs are not energy efficient. Just moving people, not cargo, will take 17% of today's US electricity."

1st, that's efficient. We can replace 45% of our oil, with 17% of our electricity.

2nd, who cares? We have plenty of electricity, and we can make a lot more cheaply and quickly with wind.

3rd, yes, 50% of US electricity comes from coal, but EV's are synergistic with wind, because they'll create night time demand (which is a greater problem for wind (and nuclear) than intermittency) as well as buffer intermittency. EV's will actually promote wind (and nuclear), and allow a greater market penetration for wind (and nuclear), at very little additional cost to the utilities. EV's will help enormously with dealing with AGW.

.

I've always responded to you ideas thoughtfully, with numbers and sources when needed

I agree and respect that. I am sorry if you see this as an ad homenium attack.

Best Hopes for debate in other areas,

Alan

Alan's perceptions above and mine overlap virtually completely.

I'm sad to hear that.

That would be giving up way too easily on understanding another viewpoint.

I wrote;

"If you build an apartment building with units having, say, 1800 sq ft with the same techniques as you build a single family home, any of the apartment units are going to consume less energy than the single family home. "

Nick wrote;

Not really - that's too simplistic. 1st, the physics also works against you. You can't put all of the windows on the south side;

Is there a need to? Are all of the windows in a single family home on the south side? To show you situations where your assertion is incorrect;

in a large building you can't use solar for water or PV

Incorrect, see picture above. And you are getting away from the point of the discussion which had to do with energy efficiency, so this is a red herring.

you won't have space for ground-based heat pumps

You provide no supporting information for this assertion, especially in the light of the Passivhaus standard requiring 90% less energy. Ground source heat pumps underground lines can be implemented in a number of ways, including wells straight down.

after a certain point A/C is working mainly to move internally generated heat, not external heat, so no further savings are possible

Unclear.

The Passive House standard sets a maximum, which an architect will design against, so energy consumption will be the same.

I can't believe someone would say this. If the same materials and approaches are used, an apartment unit of the same floorspace will require less energy than a single family home, unless in some place where practically no HVAC is used, (i.e., Maui)

In particular, exterior windows will be maximized until they hit the limit.

What limit? Where do you find this energy efficiency axiom of maximizing window area?

the absolute difference is going to be so small as to not matter

Because you say so?

For $100 savings we're going to go with apts over another form of housing?

1. You assume that an equally designed apartment is only a 20% improvement, which I find amazingly low.
2. You forget that building an apartment means shared walls, ceilings, floors, roof, etc which greatly reduce building costs.

In the long run, not many of those homes will stay vacant.

Perhaps, but then again, perhaps not. They might be taken over by squatters. Or they might be so worthless due to stripping of materials that they are bulldozed down, like many already have been.

We certainly don't need to build more homes in sprawling areas. If we are to add homes, locations near mass transit are the first place to start. And that could mean renovation of existing ones or starting over again.

Will, we seem to be arguing a bit at cross purposes, and not making progress. Perhaps I can clarify, and cut through the detail.

I think we both agree that reducing energy consumption is very important. I suspect we both like: building efficiency, rail, urban living, renewables like wind & solar, plugins over ICE vehicles, and sedans over SUV's.

My point is that building location and form (i.e., suburbs vs city, single family vs multi-unit) is much less important than energy-related design efficiency. And, in fact, that improved building design is far more cost effective, faster and easier than changes in building location and form.

We're only building 625K homes per year, and we have roughly 110M homes. We have excess & vacant homes: we're not going to be building a whole lot of new urban homes any time soon. Why are we distracting ourselves with questions of urban vs suburban? We have to work with what we have, and in fact, we can reduce energy consumption in existing homes pretty straightforwardly: for example we improved our windows, and now we don't need heat until it's below freezing outside.

Does that help?

Now, for the heck of it, a few answers on detail.

"Is there a need to?"

In general it's desirable, to maximize winter heat gain.

"Are all of the windows in a single family home on the south side?"

It's a desirable feature in a highly efficient single family home.

"To show you situations where your assertion is incorrect"

The first picture does seem to locate all of the windows on one side. Hmmm. I guess this is a multi-unit, but I'm not clear what it's illustrating. Both of your illustrations seem to be of townhouses: I would note that that they show windows that have been maximized: pretty much floor to ceiling, wall to dividing wall.

"in a large building you can't use solar for water or PV...Incorrect, see picture above."

I said a "large" building. Physics tells us that cubic feet expands as the cube of the average diameter of the building, and ceiling sq ft expands as the square: at some point, in a large building, you won't have enough space to get sufficient solar insolation (especially after you subtract roof space used for building utilities of various kinds).

"you are getting away from the point of the discussion which had to do with energy efficiency, so this is a red herring."

Well, it's closely related. At some point the marginal cost of efficiency rises above the cost of clean generation. If it costs $20K to save x amount of energy, and you can add $3K of wind power, or $10K of PV to generate it, doesn't that make more sense?

"you won't have space for ground-based heat pumps...You provide no supporting information for this assertion"

This is similar to solar. Cubic feet expands as the cube of the average diameter of the building, and building footprint sq ft expands as the square: at some point, in a large building, the ratio of demand to available ground will be a problem.

"after a certain point A/C is working mainly to move internally generated heat, not external heat, so no further savings are possible...Unclear."

Envision a perfectly insulated house: it will still need A/C: body heat, waste heat from anything electrical, etc.

"If the same materials and approaches are used"

But, they won't be. Look at the townhouse examples in your post: does the front facade look like the front of a single family? No - they've maximized the windows, front and back.

"an apartment unit of the same floorspace will require less energy than a single family home"

Not necessarily. Envision a single family with no windows on the side walls: how much heat will be lost there? Very, very little. As a practical matter, it's the windows and doors, and other holes in the walls that dictate your heat loss (or gain, for A/C). Townhouses don't have windows on the sides (except for end units), but the windows get concentrated on the front and back, and maybe you throw in a skylight or two for good measure.

"Where do you find this energy efficiency axiom of maximizing window area?"

That's just speculation, but if you give an architect a standard, they'll build to it, and maximize the things clients like, such as windows, until they meet the standard.

"the absolute difference is going to be so small as to not matter...Because you say so?"

It's just simple math: if you reduce energy consumption by 90%, the rest is really not worth much bother. Really.

"You assume that an equally designed apartment is only a 20% improvement, which I find amazingly low."

Again, they'll never be "equally designed". You might get 33%, if the client was really determined, and either didn't care much about selling the units, or was willing to pay a lot extra for a very marginal return.

"You forget that building an apartment means shared walls, ceilings, floors, roof, etc which greatly reduce building costs."

No, but we're talking about energy, not building costs. People currently choose single family homes despite the extra costs. What will change that? Not $100/year in energy costs. Especially not when they're savings 10's or 100's of thousands of dollars in land costs.

"They might be taken over by squatters."

See, this is a common blind spot. Squatters are people: if something is "taken over by squatters", it's occupied. If the area becomes a slum, and is lived in by drug dealers, it's occupied. Now, drug dealers who pay to reconnect the utilities where squatters won't, but...you get the idea.

" they might be so worthless due to stripping of materials that they are bulldozed down, like many already have been"

Sure - I acknowledged that. But, what %? Paul_the_engineer says the vacancy rate is only 1.3% over the average. If half of those are demolished (which is unlikely), that's only .65%.

"We certainly don't need to build more homes in sprawling areas."

No, and we're certainly not going to add very many anytime soon.

"If we are to add homes, locations near mass transit are the first place to start"

Sounds good. But that won't move us very quickly towards energy savings, at this rate.

" that could mean renovation of existing ones or starting over again.
"

Retrofitting is the way to go - much, much cheaper than rebuilding.

more later...

No, but we're talking about energy, not building costs.

All building material comes with embodied energy. And you keep talking about building "cheaper".

Now, drug dealers who pay to reconnect the utilities where squatters won't...

*sigh*

Not necessarily. Envision a single family with no windows on the side walls: how much heat will be lost there? Very, very little.

If you are refitting a standard R-11 suburban single family side wall, what specifically are you going to do to get it to the level of an apartment? What do you mean by "very, very little"?

Qloss = (Σ(UA)n + Cv)(ti - to)

where:

U = 1/R-value

A = area (ft2)

n = surfaces

Cv = infiltration losses

ti = indoor temperature

to = outdoor temperature, normally the coldest in the 97.5 percentile (2.5% of the time is colder)

But, what %? Paul_the_engineer says the vacancy rate is only 1.3% over the average.

Average of decades past is irrelevant in today's 2.8% (and climbing) vacancy rate. I'm afraid I can't continue a discussion with this kind of response. Let's just agree that we have different opinions and move on.

" Let's just agree that we have different opinions and move on."

That would be a pity. Most of the time I find that continued discussion makes people's ideas converge...eventually.

"Average of decades past is irrelevant in today's 2.8% (and climbing) vacancy rate."

it's important to compare todays rate to historical averages. The question is: how high is the vacancy rate, really? An increase of 1.3% is significant, but it hardly suggests that a large % of our existing housing stock is going to be demolished.

"All building material comes with embodied energy."

True - operating costs aren't the only thing that matters. That certainly suggests that construction should use sustainable materials such as wood (which sequesters carbon), and cement which consumes rather than produces CO2 ( http://www.guardian.co.uk/environment/2008/dec/31/cement-carbon-emissions ), and that we should internalize external energy costs to allow a good accounting of lifecycle costs. I haven't seen a good lifecycle analysis which quantifies such embedded costs in relation to operating costs - have you? A typical manufacturing embedded energy cost (excluding things like refining) might be 5%.D o you have a rough estimate for discussion purposes?

"you keep talking about building "cheaper"."

That was mostly in relation to retrofits. As far as new construction goes, we should keep in mind that urban housing is much more expensive than suburban, so costs are higher there. Are suburban townhouses the low-cost solution? Probably, and yet they don't seem to be popular - people seem to think the extra costs of single family homes are worth it. That's not my (or your, I presume) choice, but what will change people's minds? Not energy costs, which are small (and will continue to be small) in the large scheme of overall housing costs.

""What do you mean by "very, very little"?""

Roughly 6% of overall HVAC consumption, in a new residential building. Let's say the sidewalls are 60% of the surface area, and have no intrusions. They'll have 0% of the infiltration (including door losses and normal ventilation air changes, I'd estimate at least 50% of the heat loss - I'd welcome better stats), and about 10% of the heat loss per sq ft.

"If you are refitting a standard R-11 suburban single family side wall"

I think we were talking about a comparison of losses for new construction. If we're talking about retrofits, then it's a different set of questions. First, are you suggesting that demolition is an alternative, with good $-ROI and E-ROI? If not, the it's a question of what retrofit has the best ROI (both $ and E). It might be additional insulation, or just going with a heat-pump combined with buying wind power. The sidewall is going to be the least of your problems - elsewhere, you may have a wide range of cost-effective solutions, but again, at a certain point the most cost and energy effective thing will just be going with a heat-pump combined with buying wind power - there's no point in pushing efficiency past a certain point of marginal return.

1/R x Area(sq ft)x Delta T (temp difference in F between one side of the area and the other side - inside and outside) = Total BTU per area per hr
1/R x Area x Delta T x hours (normally 12 or 24) = Total BTU per total time
1/R x Area x 24 (hours) x Degree Days = Total BTU per area per year.

1/R = U
1/U = R
U = BTU per hour per square foot at 1 degree F temp difference
(Lots of windows give their insulation value in U so it doesn't look so pathetic compared to wall insulation. Some window sales persons will even swear that there is no connection or relationship between R and U insulation factors)

In calculating heat losses you should find the wall area and subtract the window areas and door areas from the wall to find the true wall losses and then calculate the window areas separately.

Typical window ratings from the Book SuperInsulation (in another building at the moment) are R0.04 for single pane glass windows, 1 for double pane glass with about 3/4"? spacing (from memory - R0.04 + R0.917 air space + R0.04 = R0.925 approximately)
Midwest USA 3 x 4 foot window = 1/0.04 x 12 x 70 F temp difference = 21000 BTU per hour/ 540,000 BTU per day. 1/0.04 x 12 x 24 x 8400 (degree days) = 60,480,000 BTU per year going out the window - so to speak. At 91800 BTU per gallon of propane that is 658.8 gallons per year to look out a single pane glass window. At $2.32 per gallon of propane that costs $1,528.42 which is expensive wasteful viewing!
Stuffing 2" of styrene insulation (R10) into the window opening changes things to 84 BTU/hr or 2016 BTU per day. Annual goes to 241,920 BTU per year divided by 91800 gives 2.63 gallons of propane per year costing $6.10 per year. Is it worth $1522.32 to look out of a single pane glass window?

Spread sheets work really great to layout the total areas and R values of all the parts of a structure and then easily make changes in insulation R value to see the effect on energy consumption and energy costs.

Jon,

Where the heck did you get that R value of .04 for a single pane window? It's about 95% too low!

I've had this discussion with Alan Drake, and he has agreed

Perhaps there is some misunderstanding. Common walls do save energy.

This effect shrinks due to auxiliary effects as unit sizes grow.

Free standing SFRs are inherently the most inefficient form, but city block size apartment buildings may not be the most efficient.

Duplexes (the most common housing form in New Orleans I guess) and row homes (VERY common in Baltimore) save some energy with one and two common walls and no form related losses.

Also, complex shapes that maximize surface area per sq ft and have lots of windows (see recent McMansions) are the worst.

Alan

"Perhaps there is some misunderstanding."

We went around and around on this recently, and agreed that you were primarily advocating a 60% reduction in sq ft to save energy.

"Common walls do save energy."

If all else is equal. We see from the stats that they aren't: townhouses on average are less efficient than single family houses. Windows are maximized on outside walls, plastic(!) skylights...

"This effect shrinks due to auxiliary effects as unit sizes grow."

Yes. It was striking, though, that existing 2-4 unit buildings came in last in efficiency, by a 2:1(!) margin.

"Free standing SFRs are inherently the most inefficient form"

Again, in theory, if all else was equal, but we see that it's not, and they're the most efficient in practice.

"Duplexes ...and row homes...save some energy with one and two common walls "

Once again, in theory, if all else was equal, but we see that it's not, and they're less efficient in practice.

"complex shapes that maximize surface area per sq ft and have lots of windows (see recent McMansions) are the worst."

Sure, though the quality of the windows is the most important factor. A 2'x1' single pane window in a duplex will lose more heat than 10 2'x2' thermopane windows in a McMansion (R of .04 vs R of 1).

This is like comparing a small compact car made of steel with an SUV made of composites and noticing that the steel car have higer MPG and then conclude that composites bad materials for making cars.

I dont get why building pair houses or row homes must be less efficient. Might there be some kind of scaling problem if you want manny rooms or a very big house? That ought to make the windowless back-to-back parts less usefull.

If you build apartments they wont be big in the same way as solitary houses, its a different kind of architecture. Its perfectly possible to to build a giant luxury flat but it would be hard to make it full of "bulging additions" as a poster mcmansion. And having several people living close to each other do not encourage having one large lawn each etc.

I do agree that stacking flats on top of each other and besides each other encourage smaller m2 in several ways. That is a good effect besides sharing external walls, more efficient water, sanitaion and electricity installations and using lager scale and more efficient heating and cooling systems. And with a proper design you get less materials and work used per m2 of living area making them cheaper to build.

From my pow are flats and solitary houses fairly alike each other. But most Swedish architecture, both old pre industrial, hundred year old and modern consists of simple back-to-back and stacked boxes.

I dont get why building pair houses or row homes must be less efficient.

I think the problem in the US is that most people are very much averse to the noise and other unwanted intrusions from neighbors implicit in shared walls, and aren't willing to pay enough for such living arrangements to get the efficiency features.

A 2'x1' single pane window in a duplex will lose more heat than 10 2'x2' thermopane windows in a McMansion (R of .04 vs R of 1).

I have to call you on this.  Single-pane windows have an R-value of around 0.85, or about 21 times better than what you've been claiming.

Absolutely - I just realized that. I remembered that single panes had a very low R-value, and relied on a comment by Jon Kutz elsewhere here for the specific value.

It changes somewhat the balancing point of the tradeoffs I've been talking about, but not enormously.

http://www.stanekwindowsmilwaukee.com/gallery/wiSuccessesImage.asp?ID=51
"The center of glass R-value on Stanek Windows's thermopane glass units is R 2.17 (U-Value .46) on this home. The center of glass R-value on Stanek Windows Low E & Argon thermopane glass units is R 3.0 (U-Value .333)"

http://www.chugachelectric.com/energy/windows.html
"a single pane glazed window has an approximate R-value of 0.85, while a double pane glazed window has a value of 1.5 - 2.0, a low-e double pane glazed window has a 2.4 - 3.0 rating and a low-e double pane glazed window using an argon gas fill has a 2.7 - 3.6 R-value."

Yes, as I said to E-P, I just realized that. I remembered that single panes had a very low R-value, and relied on a comment by Jon Kutz elsewhere here for the specific value.

It changes somewhat the balancing point of the tradeoffs I've been talking about, but not enormously.

"The Partnership for Advancing Technology in Housing (PATH), a program of the U.S. Department of Housing and Urban Development, has found through numerous site demonstrations that thermal mass walls offer significant savings on energy bills, especially throughout the south and in the west.

Oak Ridge National Laboratory's 2001 research on the energy efficiency of 16 different wall configurations (including stick frame, T-Mass, and ICFs) confirms this finding. The study, Thermal Mass — Energy Savings Potential in Residential Buildings, shows that concrete thermal mass walls, "applied in good contact with the interior of the building," are the most efficient wall assembly."

http://www.housingzone.com/probuilder/article/CA6275261.html

http://www.bira.ws/projects/files/Peak_Interest_Thermal_Mass.pdf

Dow T-mass walls may be to expensive for most folks ... Mag board SIPs seem to be the coming panel

http://www.toolbase.org/Building-Systems/Whole-House-Systems/fiber-cemen...

Water and soil is still the least expensive thermal mass

I don't agree with the emphasis on thermal mass. The amount of radiant energy entering a Passive House with an ideal exposure is remarkably small in predominant heating climates. The idea of thermal mass is to store solar energy to even out the daily temperature swings of a few degrees. So how much storage do you need for a small amount of solar heat gain for a single day? For Passive Houses, extra thick 'thermal' layer of drywall(5/8" instead of 1/2") will provide enough solar gain storage to keep the daily swing in temperature down to a few of degrees.

Of course if you don't have a nice unobstructed south exposure in January you're pretty much out of luck anyways.

I agree that in most climates thermal mass is a mistake. The exception may be hot dry climates (e.g. Middle East or Mediterranean or SW-USA) where it is hot during the day but quite cool at night. Most people in southern Europe or in the Middle East do not have air conditioning but rather open the windows at night to let the house cool down and close the windows and block the sunlight during the day.

In other climates you really want to minimize thermal mass so that when you come home in the evening you can minimize the mass you need to heat or cool.

For Passive houses, with or without solar gain, the temperature stays stable just with the normal thermal mass of normal walls, ceilings, furniture, etc.

Passivhaus insulation standards is the only energy saving construction idea that makes sense. Solar, earth shelter, thermal mass, straw bale, etc. are all more expensive, less practical, and do not work as well.

I guess insulation has little sex appeal.

A thermal mass inside the insulation do not increase the heating needs exept for minor effects such as any increase in insulated volume and higher density needed to carry the weight.

The need for storing heat energy for a day is relevant for all parts of the globe with night and day cycles. Personally I would like a house to be slowly regulated withe enough mass handle a few days power failure in winter withouth freezing, a cold spell with a slight decrease in temperature and a few hot summer days withiuth airconditioning. It makes sence with the local climate.

Earth shelter is probably good in climates with a low difference between short term average outside temperature and the house temperature. Why use lots of insuation when you dont need to have a temperature differential to insulate against?

Straw bale houses makes sense for me as ultra low cost building, especially if you got cheap fuel for heating.

If you have very good insulation thermal mass will do nothing since heat will not be lost or gained. If you do not have very good insulation, thermal mass helps regulate temperature, but not nearly as well as additional insulation. Thermal mass is also far more expensive than insulation because it needs to be transported and supported by the structure.

How about this for a rule of thumb: If you need to heat or cool your house, thermal mass is bad. Insulation always does a better job of regulating temperature.

This is because when you come home in the evening will have cooled down and you will need a big heater to warm it up in a reasonable amount of time. If you insulate your house to the point that you get the same drop in temperature while you are away, you will be able to heat it back up with less energy since there is much less to heat up.

If you live in a cold place and loose power you will stay warm in a Passive house--indefinitely--not just for a few days.

Obviously, if you live in a very good climate you could live in a tent, keep in mind that the passivhaus specifications are not for a specific insulation value, but for a maximum heat transfer (per square meter living space), so in Hawaii you might need a couple of cm of foam, but in Moscow you would need about 1 meter.

I would be interested in seeing some cost numbers for straw bale houses. It is not obvious to me why they would be cheap.

I get your reasoning but thermal mass is still usefull if you need to store heat from daytime passive solar or buy night rate electricity for supplemental heating. But I am to tired to make a back of the envelope calculation about how much is enough.

The cost for straw bale houses probably depend very strongly on the kind of house you aim for, where you build and so on.

I am quite sure there is no one-size-fits all soution for building houses. Btw, one of my favorite oddball ideas were a couple who wanted a winter garden and built an old style log house inside a big greenhouse.

You make a reasonable argument, but it runs contrary to my personal experience living in a well insulated house with lots of thermal mass. But, you may be correct.

I would really like to see an experiment of 2 similar houses built here in Wisconsin that use passive solar techniques along with super insulation and thermal mass. One house would be built like ours out of tilt-up concrete (floors, walls & ceilings) and the other conventional stick construction. Both would use the same amount of substantial insulation. Or, perhaps the concrete house would use a little less insulation to arrive at equal R values - would that be a fair comparison?

Then many factors could be evaluated - of course life time costs would be one. But, also things that contribute to one's quality of life (obviously much more subjective). For example, it was very easy for us to have tile floors and plastered walls because of the concrete surfaces. The house is extremely quiet and the radiant aspects of the concrete allow a higher comfort at a lower thermostat setting. Lots of things could be measured and evaluated - would be interesting to see. I started building our house nearly 30 years ago and tried to use the princples in fashion at the time - maybe we have better information now. But, here in Wisconsin, I've not seen much experimentation beyound insulation levels and air management - ventilation issues.

If you need to heat or cool your house, thermal mass is bad. Insulation always does a better job of regulating temperature.

I'd be interested in seeing analyses and/or case studies from you showing the engineering modeling to support such a claim. In some places, thermal mass alone works best, such as in moderate climates (i.e., the Mediterranean, Southern California) that have warmer days and cool nights. I've yet to hear of cooling by insulation alone, but I'm open to finding out.

I lived for years close to the Mediterranean and even though nobody had air conditioning it was almost always cooler inside on hot days because of the high thermal mass of the buildings. The interiors would warm up a lot over the course of the day but soon as the sun went down you would open the window and let in a cool breeze. A couple of hours after sunrise you would close the windows (and the shades to keep out the sun). There is a large temperature swing inside but much less than on the outside. There was no insulation. But what if you add some insulation to the picture? In such a climate you would add it to the outside and slow down the infiltration of heat during the day. Adding insulation would have the same effect as adding a whole lot more thermal mass since the buffering effect would be isolated to the inside of the dwelling.

Remember also that the Mediterranean climate also has a winter and thermal mass does not help when it is cold also during the day.

I mention this above or below, but insulation has a multiplying effect on thermal mass. In a passivhaus, the inside warms up in the summer due to body heat and waste heat from lighting or appliances. But you can play the same trick with windows, opening them at night and closing them during the day. You need less thermal mass because you and your appliances are the only sources of heat gain, and that can be adequately buffered with the thermal mass of you drywall and furniture. If your days and nights are hot you could get by with a very small air conditioner. I have also heard of using buried tubes to cool incoming air.

Obviously, if you live in a very good climate you could live in a tent

There's something to that... since you mention Hawaii, I'll note that when building my house here I just designed it to keep the rain out; single-wall, no insulation, high ceilings, lots of ventilation, and an enameled metal roof to channel the rainwater for storage or irrigation as necessary. It's the dead of winter now and the windows stay open. Good place for a future famine, though, particularly on Oahu, so there are always tradeoffs. Land's cheap on the big isle here.... 3 acres on pavement for $33k or so. If you go to some lengths to relocate to a place you can build a passive house out of anything, is that passive-aggressive?

There is a definite advantage to thermal mass in shifting the running time of air to air heat pumps and air conditioners. This allows you to run the equipment more at times of minimum differential temperatrue, increasing the efficiency.

Studies have shown thermal mass to save 8-10% of heating and cooling energy.

This is just a ramble, I'm aftaid:

My wife and I built what we hoped would be a passive house, in NH, but there are too many cloudy winter days around here. We use a small (Jotul #3) wood stove for heat. The house has various kinds of thermal mass including the interior pine timber frame and the chimney that runs up through two northwest rooms (a brick "enclosure" for the wood stove is embedded in an interior wall, the stove in the living room and the chimney in the adjoining room. We also doubled or tripled up on sheet rock walls that would be illuminated by sunshine, by adding random scraps between the joists on interior walls. Overnight the stove cools and room temperature drops maybe 8 - 12 degrees. On sunny days we can ignore the stove during 4-6 hours of midday.

The house does get cold when we go away - if we're gone for 2-3 days it can take 2-3 days to feel warm again (cold walls will make you feel cold in 72-degree air).

The house is 24' x 36' x two stories and is well insulated with Structural insulated panels (SIPs). I bought 3 big expensive custom windows for the south side that reflect far-infrared (black body radiation) back into the house. The house was far too expensive to be a general solution, so although we're happy we are disappointed we didn't create a "solution" of any particular value.

We didn't mix radiant with passive solar; an elderly cousin did and she has to open doors in sunny afternoons to dump heat that can get the temperature over 80. I have read and heard that passive solar and radiant do not mix well.

A well known timber framer around here has been interested in cheap housing (including energy) and he believes in extra insulation + PV + a heat pump -- a heat pump of the future, I would imagine - there is a Scandanavian company he mentioned that uses a different fluid (I think) to achieve heating even on seriously sub-zero temperatures. He would heat water with electricity also, to keep total costs down. Since SIP panels are maufactured (require energy) he is experimenting with home-made SIP-like panels that are filled with cellulose insulation. Our timber-framer, a neighbor, designed a one story barn which a small crowd of men could put up mostly by hand. I would like to see these ideas evolve into something affordable and good.

Straw bale houses can be built with hand labor and "available" materials which probably means they could be pretty cheap. There is one such house in the next town that is gorgeous - looks like adobe, was designed by an art student -and probably costly. But over time we could (as a "culture") learn how to build them.

For my own house, if family wants to move in with us, I think I would build a less-well-insulated wing for bedrooms. We could spend daytimes in the warm "core" and sleep in cold fresh air. This is essentially the same stragegy used by owners of big old arks who basically retreat to a few rooms during winters.

I notice Corning is entering the market for fiberglass-like windows (like Marvin's "Integrity" line. I'd love to see prices for good windows go down a lot.

We are making "window quilts" (r-7) which the normal so-called Low-E windows, R-3, require.

We're all learning. I should look for a blog somewhere on the subject of housing.

I've visited mobile homes volunteering to "weatherize" but they're pathetic.

Pella now makes fiberglass (FRP) framed windows. They are 5 times stronger than vinyl. Cost for 16 custom smaller than typical windows for my house was about $6000.

It's ironic that the aluminum clad wooden framed windows are the high end price wise but not comparable in durability to the fiberglass framed. The advantage of wood is that it conducts less heat than FRP, but the area of FRP is minimized.

Cellular shades are the ultimate cure to heat transfer thtough windows. Less than $200 per shade ratings R3 to R4 typical.

Just a warning.
Pella windows do not meet Passive House standards.
The ratings of almost all US manufacturers are highly suspect and have always failed analysis by Passive House analysis. Many German companies make compliant window assemblies and a couple of Canadian firms do also.

Names of the Canadian companies ?

Thanks

Alan

I'm drawing a blank on Canadian but will post when I find out where I wrote iot down.

Here's a German maker(there are a lot).

http://www.optiwin.net/optiwin-window-systems/view?set_language=en

US architects and building engineers are too ignorant and set in their ways to 'fall into' this.

If you want to learn all the secrets
you really need to get trained.
There is just TOO much misinformation out there.

http://www.passivehouse.us/passiveHouse/PHIUSHome.html

Any idea how cob, rammed earth or straw bale perform compared to T-mass? And, I would be loath to use styrofoam in my home.

Cheers

The Passive House people are VERY concerned with using environmental materials.
They love styrofoam for its R-value and its incompressibility but worry about the possible CFC blowing agent.
The best materials are mineral wool and glass beads under the foundation.
Cellulose, especially recycled blue jeans are good but they worry about losing mass/ thickness from settling over time.
They prefer glue to nails, but if you need nails use stainless steel nails which have lower thermal conductivity.

As for straw bales, earth and cobs, there are insect issues and compressibility. Homes should be designed to last and be moisture resistant.

"As for straw bales, earth and cobs, there are insect issues and compressibility. Homes should be designed to last and be moisture resistant."

I can't find the source right now, but it seems to me that I have read about rammed earth structures that have been in continuous use in China for thousands of years. I think the earth is so compressed that insects and other beasties don't bother trying to burrow in it.

I'd love it if someone could find a reference, though. It could be my old brain playing tricks with memory on me.

As for straw bales, earth and cobs, there are insect issues and compressibility.

It's hard to imagine a problem with compression with clay. How so? Where do you get your info re: water and bugs. I cannot confirm either of these problems in a properly designed home.

R-value of straw bale is up to 45. Styrofoam is...? I have no idea of the R-value of rammed earth or cob.

Homes should be designed to last and be moisture resistant.

There appear to be straw bale and cob homes that are hundreds of years old, so... Where do you get your info on this issue?

Finally.... styrofoam? Glass beads? Blue jeans? Glue? Where, pray tell, does sustainability come in? For if it doesn't, you are most assuredly spittin' in the wind.

Thanks,

Cheers

Styrofoam is much more "sustainable" than straw bale and a much better insulator. Buy yourself a few acres and grow enough straw for a house and you will see how much (fossil) energy is embedded in that straw.

Only as long as the low energy of the oil and gas industry exists, after that straw rules when you use animals for the inputs. That by the way includes humans!

A fair point in your narrow way of thinking, but the straw is at present waste material, thus is recycling and reducing CO2 emissions. Also, when we say straw, well, we are really just talking grasses. Because of how the ag industry is set up now, the straw comes from there. Had I a field of high grasses and scythe, I'd have no problem making my own straw, now would I?

Styrofoam is sustainable? When pigs fly. Straw can be had with zero FF inputs. Perhaps in the future it will be again. For now, it is hardly a negative to put it into walls instead of burning it.

Extremism in any form is usually not the best solution. Nothing you are advocating is sustainable. I do applaud your interest in using less energy, but that is only part of the battle. Your ranting AGAINST other forms of construction is, frankly, bizarre.

Simple is as simple does, friend, and you are starting to get irritating.

Cheers

I don't think I am ranting, am I?

Straw is not a waste material anywhere.
I don't want to rant, but you will have real difficulty anywhere in the world to find straw produced, baled and transported without fossil fuels.

I agree that straw bale houses are more natural, in some reasonable sense of the word. In a world with a few million people or tens of millions, straw bale houses or log cabins would be perfectly reasonable, but they are not scalable at all. In a world with 8 billion people, nothing is sustainable, but in my opinion, materials like styrofoam reduce fossil fuel consumption because the vast majority of people in the world burn large amounts of fossil fuels to heat poorly insulated houses. What do you heat with?

By the way, styrofoam is gets its name from the Styrax tree, so you could make it "sustainably" (if you put enough energy (renewable, obviously) into it, so styrofoam can be had with zero FF inputs ;-)

Yes, you are ranting. It is not rational to claim one kind of construction is superior to all others at all times for all people, which is what you are basically doing. And some of what you have said is just nonsense.

Straw is not a waste material anywhere.

WTH is wrong with you? If it is being thrown away and/or burned, it is waste.

you will have real difficulty anywhere in the world to find straw produced, baled and transported without fossil fuels.

You are tiresome. As this applies to everything, the point is moot. Purely argumentative.

In a world with a few million people or tens of millions, straw bale houses or log cabins would be perfectly reasonable, but they are not scalable at all.

Were your argument accurate, it would be all the more true of your passivhaus obsession. However, it is utterly scalable.

1. I do not talk of only log cabins and straw bale. You are the only one advocating only one kind of construction. I am advocating all kinds, case by case, which makes my plan far more sustainable and far more reproducible than your plan, hands down.

2. Passivhaus is utterly unscalable as it is unaffordable to many and may come up against some serious resource constraints at the global level.

3. Passivhaus is not DIY. "Earth" homes are.Your position is inherently unsustainable as the majority of the planet cannot afford a passivhaus, but anyone can make mud and pile it up to make walls. Or bale hay. Etc., etc.

materials like styrofoam reduce fossil fuel consumption because the vast majority of people in the world burn large amounts of fossil fuels to heat poorly insulated houses.

And, so, retrofit. Why are you arguing something I have not argued?

By the way, styrofoam is gets its name from the Styrax tree, so you could make it "sustainably" (if you put enough energy (renewable, obviously) into it, so styrofoam can be had with zero FF inputs ;-)

Sure. Everyone's got 'em in their yards.

Aigoo...

I suspect that you might be ranting. If straw is free and plentiful and renewable, why bother with insulation at all, just burn straw to stay warm. A passive house is nothing special, nothing high tech or complicated, just very well insulated. You could use straw to insulate and make as straw bale passive house. In central Europe you would need a bale thickness of about 1 meter--doable. Or insulate with whatever suits you. I know someone in Germany who insulated with shredded hemp. My only point is that insulation is important and a very cheap way to reduce fossil fuel dependence. I feel that you are also discounting the embedded fossil fuel content of agricultural products...

...I used to live in a small village without mechanized agriculture. The peasants walked to the field or rode a bike, straw was cut with a sythe, collected with a rake made from sticks and hauled to town with a handmade wooden cart pulled by a pair of oxen. The process was entirely fossil fuel free. I can assure you that once you have collected your straw this way you will not give it away and will not waste it. You will use it to feed to your animals in the winter or as bedding. You would need a lot of land and years of work to collect enough straw for a house. Straw bale houses, at least those of the size they are built today, are a luxury enabled by fossil fuel and highly mechanized agriculture.

I feel that you are also discounting the embedded fossil fuel content of agricultural products...

You may "feel" whatever you wish, but you are just making stuff up. Why do you not answer my questions, and why do you ignore other comments made?

Boring.

BTW, straw bale IS insulation. That is its purpose. Most use it in a non-load bearing technique.

Enough.

Straw is also thermal mass. There are technical advantages of both high and low mass insulation.

In New Orleans, low mass is to be preferred. In Baltimore, high mass insulation should be preferred (ANY insulation is better than none).

ALan

I apologize if misinterpreted one of your comments. I agree 100% that straw can be used to insulate. But the original and by far most common purpose of a straw bale is to transport and store it for use in a barn to feed animals. I also agree that it would be a good idea to retrofit houses to have better insulation (but I would not use straw...).

I you do build a straw bale house, consider building it to passivhaus standards so you could minimize your supplemental heating.

"But the original and by far most common purpose of a straw bale is to transport and store it for use in a barn to feed animals."

I think you may be confusing straw with hay.

Hay is dried grass; straw is the hollow stems left over after grains have been harvested.

As a boy who grew up in town, I was once sent out to a farm to pick up a bale of straw for my girlfriend's dad. I came back with hay, and he explained the difference.

I do know the difference. Both are used as feed, although hay is more nutritious.

Yes Will, I know what straw is. That's why I posted my comment.

Our horses and cows wouldn't eat straw. (Oat straw) (Well, I suppose they might have if nothing else were available - kids in Haiti eat dirt for the same reason.)

Growing up on a farm I never heard of anybody feeding straw to their animals.

Sorry, wasn't directing my post to you. My sheep don't eat straw either.

Biophilia:
Not doubting your good intentions, but your analysis and data is a little off..

http://en.wikipedia.org/wiki/Styrofoam
http://en.wikipedia.org/wiki/Polystyrene

Styrofoam is a trademark of Dow Chemical Company for extruded polystyrene foam presently made for thermal insulation and craft applications [1].

In 1941, researchers in Dow's Chemical Physics Lab found a way to make foamed polystyrene. Led by Ray McIntire, they had "rediscovered" a method first discovered by Swedish inventor C. G. Munters.[2] Dow acquired exclusive rights to use Munter's patents and found ways to make large quantities of extruded polystyrene as a closed cell foam that resisted moisture. Because of its insulating properties, buoyancy and "unsinkability", it was adopted in 1942 by the U.S. Coast Guard for use in a six-person life raft.

Polystyrene IPA: /ˌpɒliˈstaɪriːn/ (IUPAC Poly(1-phenylethane-1,2-diyl)), sometimes abbreviated PS, is an aromatic polymer made from the aromatic monomer styrene, a liquid hydrocarbon that is commercially manufactured from petroleum by the chemical industry.

Products made from foamed polystyrene are nearly ubiquitous, for example packing materials, insulation, and foam drinks cups. Discarded polystyrene, which does not biodegrade, is often abundant in the outdoor environment, particularly along shores and waterways.

http://en.wikipedia.org/wiki/Styrax

Uses of resin

Benzoin resin, a dried exudation from pierced bark, is currently produced from various Styrax species native to Sumatra, Java, and Thailand. Commonly traded are the resins of S. tonkinensis (Siam benzoin), S. benzoin (Sumatra benzoin), and S. benzoides. The name "benzoin" is probably derived from Arabic lubān jāwī (لبان خاوي, "Javan frankincense"); compare the obsolete terms "gum benjamin" and "benjoin". This incidentally shows that the Arabs were aware of the origin of these resins, and that by the late Middle Ages at latest international trade in them was probably of major importance.

The chemical benzoin (2-Hydroxy-2-phenylacetophenone), despite the apparent similarity of the name, is not contained in benzoin resin in measurable quantities. However, benzoin resin does contain small amounts of the hydrocarbon styrene, named however for Levant styrax (from Liquidambar orientalis), from which it was first isolated, and not for the genus Styrax itself; styrene is used to produce polystyrene plastics, including StyrofoamTM.

You've both been ranting. Somebody tell a joke, please!

Sorry for the rant. I know that EPS (Styrofoam) is make from petroleum. But my point is that for a similar insulation value, (hypothesis) you will consume more petroleum to insulate with almost any agricultural product, particularly straw, than you will with EPS. If you had no fossil fuels, you would probably not be able to produce enough straw to make a house (and feed yourself). There are probably not to many people who on TOD who have experienced agriculture without fossil fuels (Airdale comes to mind), but you do not generate very much surplus and you do not waste anything. I doubt too many straw bale houses were made in the pre-FF era. People favored materials that they did not need to make themselves and that could be gathered in the winter (stone, wood, bricks, mud), so you could grow food in the summer and build in the winter.

Actually your first paragraph is all wet.

Straw is not a waste material. Straw is stubble that has been carefully dried and collected at cost in energy and time. The alternative is to let the stubble rot in the field. If someone has a bale of straw it is not waste.

Next, 'straw bale construction' really does mean 'straw'. I live in New England, where there is little to no local straw because there is little to no local grain production. We do have plenty of hay. Hay bales have different compressibility, moisture transmission and vermin attractiveness characteristics than straw bales. A blind substitution on materials on the basis that both are dried grass has a very low chance of success. (Been tried many times. Failed 0.9xmany)

A field of high grass whose seed heads have matured can be made into straw if and only if you have the additional technology to remove the seeds. This may be as simple as a flail and a winnowing widget, but is non zero.If the seed heads have not matured, straw is impossible.

Once you have straw, you then need to make bales. This requires serious additional technology. I'm not sure how difficult it would be to make a animal-driven baling machine. I do know that the Amish use horse-drawn diesel powered balers.

Frank

Hay bales have different compressibility, moisture transmission and vermin attractiveness characteristics than straw bales.

True. While the first cuttings some types of grass approach the appearance of straw, they still have a substantial amount of 'leaf'. If push came to shove, a 1st cutting of fescue might be substituted, but straw should always be the first choice.

I'm not sure how difficult it would be to make a animal-driven baling machine.

Ground-drive square balers existed in the past, though had limited performance in comparison to powered balers. Some are still used today and horse-powered farming is seeing (an albeit small) renaissance.

Aigoo... IF straw is being burned, it is being treated as waste material, though it may also be burned as a form of fertilizer. IF it is being thrown away, it is waste material. Lots of straw gets thrown away or burned. THUS, if you instead use it to build a house you are creating a carbon sink where there would have been carbon emissions.

This ain't rocket science, folks.

NOTE: straw is best left in the field to act as a mulch, or used for feed or building if it would otherwise be disposed of or burnt.

A field of high grass whose seed heads have matured can be made into straw if and only if you have the additional technology to remove the seeds. This may be as simple as a flail and a winnowing widget, but is non zero.If the seed heads have not matured, straw is impossible.

Where there is a will, there's a way. And, by your own description above, I was not wrong. You clearly state it can be made into straw. I never said easily so.

As for the rest, thanks for the info.

It seems to me, the future for us will be living underground...........climate change and all that.....might be safer from bombs too.
http://www.outback-australia-travel-secrets.com/coober-pedy-underground-...

My wife dreams of an underground house, as in Hobbitt House Lord of Rings thingy. Hmmm, I could build one I suppose. Ohhh Coober Pedy, that is definitely the exception to every rule.

Glenn, it's great to see a post/discussion about the European Passive House Standard. I have been learning more and more about this standand over the last year.

I feel that new terminology is needed for this type of building design. I share your concern about the word "passive". I would dare say that the majority of people involved with house design hear this word and then automatically assume "passive solar". Althought passive solar is ONE of the design elements in the Passive House standard the key element is what some refer to as "super insulation". Super insulation does not refer to a new type of insulation, but rather "super amounts" of standard insulation.

Some of the case studies that I've reviewed have houses with R100 insulation in the attic. This amount of insulation is basically unheard of in my corner of the world in Eastern Canada. The current norm for new construction here is R30 to R40 for the attic and don't forget that our climate in Canada is colder than the majority of locations where Passive Houses have been built in Europe. My opinion is that these houses should be referred to as Super-Insulated Passive Solar houses. I know that it's a tad wordy, but time and time again I find that people miss the key fact about this type of construction. Roughly speaking 60% of the space heat in a house is lost through the ceiling, walls and foundation components. The super high amounts of insulation typically used in Passive Houses produce a 80-90% reduction in heat loss through these parts of the house.

- Substantially higher amounts of insulation
- Substantially reduced thermal bridging and
- Substantially reduce air infiltration

It's the combination of these three items that produces the greatest energy savings for this type of construction standard.

"Basements are either eliminated or serve as unheated storage only."

This seems odd to me; why not use the basement space? From what I've gathered, deep underground temperatures are the average of aboveground temperatures, and insulating against underground temperatures would mean insulating against a much more mildly swinging temperature than that of the outside air.

The books I have on earth-sheltered building and earthbag building usually feature a sunken groundfloor in their plans, both to save on work for the outsidewalls and because the earth itself is useful thermalmass.

Equally, the use of thermal mass could be exchanged for insulation that would be more effective than insulation against the outside temperature, since heat conduction is a function of temperature differences.

The books I have on earth-sheltered building and earthbag building usually feature a sunken groundfloor in their plans, both to save on work for the outsidewalls and because the earth itself is useful thermalmass.

I had the same thought. The thermal mass of the earth itself essentially protects against freezing in an emergency and provides cooling in hot periods. Color me confused.

Cheers

Hi ccpo,

The following guide suggests the heat loss through an un-insulated basement floor is in the order of 2 BTUs/ft2, so if the basement is 1,000 sq. ft. (93 m2), the losses over a 24-hour period could be in the range of 14 kWh, or about 430 kWh/month.

Source: http://www.ced.berkeley.edu/courses/sp08/arch140/2008/Documents/Readings...

Our heating season is effectively October through May -- eight months -- so, if this estimate is more or less correct, the heat loss through a slab this size would be just over 3,400 kWh/yr.

Comfort is another factor. In Canada, our winter temperatures can dip below -30C and you don't want to be walking on a cold concrete floor.

Edit: One other thing comes to mind -- living in a maritime climate, our soils (predominately fine clay) have a relatively high moisture content so, consequently, our rate of heat loss is likely to be significantly higher.

Cheers,
Paul

Insulation is much better than thermal mass. A Passive house will stay warm and comfortable as long as it is inhabited.

Someone's got an agenda.

Personally, the day I find a one-size-fits-all way to build homes I'll consider myself soon-to-be very,very rich.

Also, see my comments re: sustainability and get back to me.

Cheers

That's a False Dichotomy, Bio.

Why would it have to be either/or? I would not really consider building without both, AND having considerable sub-frostline exposure (basement), while I wouldn't be wasting my wood or solar-heat trying to warm the basement floor or walls.. they would be busy warming the incoming air, and I'd likely be standing on raised flooring down there.

Keep in mind that there is ton of thermal mass in a house without adding extra. Also, thermal mass is a relative metric that depends entirely on the insulation level--a little thermal mass goes a long way in a well insulated house. Conversely, if you sleep out on a rock somewhere you will have 6×10^24 Kg of mass right next to you, but you will still be cold.

For cooling, thermal mass (the earth beneath you) makes a lot of sense since it will usually be cool. Some Passive houses pull in air through a buried tube to cool in the summer.

Personally, I like massive houses and prefer the heavy masonry or stone houses that are common in central and southern Europe over the flimsy cheapo houses in N. America. But if I had such a heavy house, I would put the insulation on the inside of the walls so I wouldn't have to keep the bricks warm.

"For cooling, thermal mass (the earth beneath you) makes a lot of sense since it will usually be cool."

As I mentioned elsewhere, this 'cool' ground beneath is also warm relative to the winter air temps, and works as a warm (45deg) fresh air source in wintertime.. adding a great deal of energy to the mix compared to bringing in combustion air right from outside.

This 'cool tube' was a welcome temperature base in every season in our 1980 Maine White Mountains home. In addition to the Massy Masonry Stove, this was a feature I wouldn't dream of leaving out of a house design.

Best,
Bob

Indeed. At a certain depth, depending on climate (12' typ.?) the temperature is constant year around and is approx. equal to the average year round air temperature.

As the building imparts heat to the earth beneath it a gradient is established in the downward direction. At some point in time [months] depending on climate and interior temperature, this gradient reaches a steady state and all heat loss in a direction perpendicular to the floor goes asymptotically to zero. The only heat loss then is at the perimeter of the building, and stemwall insulation is as effective as under-slab or floor insulation.

This provides thermal ballast, which of course is not needed so much for a "super insulated" structure, but can mitigate excessive temperature swings if there is an abundance of solar glazing.

The caveat here is that the building will have a heat loss through the floor in the downward direction until the downward gradient reaches steady state, and that may be as long as one full heating season depending on floor area and, of course, climate.

Additionally, the slab in contact with the ground need not be a main living area. It can be a basement, for example, or utility room, or just a crawl space. The floor of the living area can be insulated or heated. Another solution is radiant heating for the basement if it will be used. (Yes, screws up the passivhaus design... but do I care? Not if my house is comfortable and cheap to heat/cool.)

While they are too expensive for my tastes, don't seem to be sustainable on large scales, and are definitely not DIY-ready, the Enertia homes are good examples of the use of the ground in this manner.

http://www.enertia.com/Science/HowItWorks/tabid/68/Default.aspx

Cheers

Majorian,

Is there some information on building costs and payback time of the investments? Not only the regular detached family home, but also for the apartment buildings etc.

Thanks

Yes, but it's very dependent of the precise climate you are in. Obviously a Passive House in Duluth, Mn and a Passive House in Mobile, Al are completely different animals. Remember these are custom houses but also that these are typically smaller than McMansions. European homes have fewer square feet per inhabitant, use less domestic water, etc.
The short answer is that Passive Houses are about 10% more expensive to construct than similar sized standard US housing.
They are not to be crammed full of electricity-sucking appliances as those could overheat the home.
Apartment buildings actually have a slightly different standard that detached homes.
If you want to see if a house meets the standard you need to work with a Passive House Consultant. If the house fails to meet the standard it may be a VERY energy efficient home but it can't be called a Passive House. So the certification is very much about making a personal statement.

Majorian,

Building a house in the Netherlands is about 400-500 euro / m3. This includes labor, material, architect etc, but excludes the land. (That is around 500 euro per m2, so 250 keuro for a 500 m2 plot, the average new-build lot size, but that is not relevant for this discussion)

Let's assume 450 euro/m3 and let's build an average home: 600 m3. That's about 300 keuro. (This is a bit on the low side)

The average home (detached) in the Netherlands uses 1850 m3 of natural gas for heating and 3400 kWh of electricity.

For NG, you pay 145 euro fixed and 0.70 ct/m3 variable. That's a total of 1450 euro. For electricity, you pay 100 euro fixed and 22 cts/kWh. Total of 850 euro for power.

So the total NG + electricity bill is 2300 euro per year.

Let's say that you are capable of making the home perfectly passive for only 15% of the building costs. I find that a bit optimistic, but let's assume for arguments sake.

That would cost 45.000 euro to do so. Assume a mortgage of 5%, from which half is tax deductible so 2.5% financing costs. Let's also assume 2.5% inflation, so net no financing costs. (But there is a 2.5% cash flow, which you should be able to finance)

Conclusion: it will take 45.000/2300 = 20 years to get your money back.

People live on average 10 years in their home, so it is not so clear you get your money back at all.

I think I just put on a sweater ;-)

Thanks for running the numbers. Don't forget increased resale value :)

The number I have heard is an additional 10% for Passivhaus construction. More recently I have heard that there is no cost difference, presumably because of experience with the construction and more suppliers of highly insulated windows and doors. You can now even get prefabricated Passivhäuser.

They are also much more comfortable and quiet.

Wonderful but total fairy dust. Noone is building new houses to any degree for a long time to come and most of those will be cheap and cheerful not dripping with capital costs.
And even if they are building there are millions and millions of homes thast would cost multiples in sunk energy to demolish and rebuild of any potential savings.
How about an article that doesn't apply to 98% of us and discuss refurb of existing stock on a ROI basis ?

I disagree.
The average age of US housing is 33 years and climbing and many of the new home recently constructed are too big for practical use as they were built to maximize square footage and therefore 'value' for speculation.

The US tax code depreciates residential property over 27.5 years, commercial over 39 years.

The US has proved it can build a lot of homes--~2 million units per year.

By condemning older homes and building new super efficient ones in their place we can reduce overall US energy consumption(~20% of energy demand~20 quads) tremendously.

If we simply do a bit of insulation here and a bit of new windows there we will be stuck with perhaps a 10% reduction in energy use and a lot of aging buildings continuing to waste only slight less energy than before. Also, it can cost as much or more to renovate a house as to build a new one.

Is a 1-2% overall energy reduction good enough?

If we can afford McMansions we can certainly afford Passive Houses.

US maybe, Europe no. In the UK we replace about 0.5% annually - the maths isn't pretty and that was before the bust. In most inner cities over half the stock is pre 1919.
So you're plan is to demolish the historical housing stock ? What's the embedded energy and payback cost of reuilding ?
10% ? No - I dropped 40% with condensing boiler, weather compensating controls, loft insulation, draught proofing and underfloor insulation for about £5k cost - payback in 4-5 years.
There are plenty of examples of full refurbs inc. external insulation and advanced secondary glazing that would take a huge chunk off energy use. Funnily enough the goverment is utterly silent on grants for solid walled houses.
These articles are jolly interesting for Quentin the rich architect looking to build his dream home for the brood and 2 nannies with somehwere to winter the yacht but for Mr average they are meaningless. At the current replacement rate his great-great-great-grand children would be average in line for a nice new house built to 2100 specifications.
Of course most of the crap built since the 70s would have fallen down a long time before that ...

US maybe, Europe no. In the UK we replace about 0.5% annually - the maths isn't pretty and that was before the bust. In most inner cities over half the stock is pre 1919.
So you're plan is to demolish the historical housing stock ? What's the embedded energy and payback cost of reuilding ?
10% ? No - I dropped 40% with condensing boiler, weather compensating controls, loft insulation, draught proofing and underfloor insulation for about £5k cost - payback in 4-5 years.

I realize you're not 'made of money'.
Britain has a much better climate for passive houses than the US, so probably more housing can be retrofit. Suppose you
go from 270 kwh/m2 to 120 kwh/m2 for a 100m2 house with $.20/kwh primary energy? that's a savings of $3000 per year. A 100 m2 house costs $100000? so you have a 33 year payback.

Yes, I'm ignoring the actual price of UK electricity and the insane recent prices of real estate(which I don't know) but the end product is green, non-polluting and insulated from a future escalation in energy prices which many here see as inevitable.

If energy is a national security issue
I think the government should pay to replace old homes with new passive homes.
In Germany I heard that part of the economic stimulus is to make Passive Homes the standard for all new dwelling units. Create sustainable jobs and sustainable dwellings at the same time.
Is there a better reason to spend tax dollars?

Passivehouses don't need central heating which is the best economy of all. Domestic hot water is another matter.

In Solar Today magazine for Nov-Dec 2008 you will find an article by local Mass. builder Carter Scott (you can view the magazine online).

As an entry in a statewide competition, Carter built a "zero energy" home which also meets criteria for affordable housing in the town. Carter does that math and demonstrates that the house - with a worst-case heat demand of just over 3000 watts - actually costs less than an equally-sized conventional home.

As others on this forum have indicated, you can get rid of the central heating and air-conditioning system and replace it with a much smaller unit (in this case a split-head air-to-air heat pump). It has a single heater unit for the ground floor and one for the upstairs, both fed from an external heat pump.

The house looks like a conventional small Cape. Since it's not a passive solar-heated house, it consumes some energy during heating season, and pays it back on sunny days by spinning the electric meter backwards - the south-facing roof is covered with solar PV panels - thus attaining its "zero energy" designation, when averaged over a year.

New housing should all aim for such high targets.

I agree with other comments here though, that the real problem we face is the existing housing stock - particularly as we can expect a long and severe downturn in the building industry, the rate of new building will be a fraction of its frenzied pace a few years ago, and we have an excess of housing now anyway, by any reasonable standard. The capital required to build new, or to tear down and rebuild, may be hard to come by for a long time. Re-training the ravaged construction industry workforce to learn how to renovate old housing to tough energy-efficiency standards should be a high priority.

Pat Murphy of Community Solutions estimates an aggressive retrofit of a conventional single-family home (for 75% to 80% reduction in energy consumption) to cost upwards of $40K - a huge expense for the typical family, but a necessary one if we're to live in our present housing stock through the mid-21st century. How will we heat homes decades after the global peaks of oil and natural gas?

This will be the topic of Pat's next book, by the way.

- Dick Lawrence
ASPO-USA

Well natural gas is typically 3p kWh and electricity 12p so annually that's £450 using your example.
A 100m2 house here costs way more than $100k - knockdown and rebuild is £100,000 according to BICS.
So payback is 222 years ignoring cost of capital borrowing.
Perhaps one could argue that if energy goes up to 5 times current prices it will pay back quicker BUT that also pushes up all costs radically.
Face it, we're talking about the 0.5% of houses replaced each year and nothing else. Yes, new houses must be built to the highest spec possible but the replacement rate is insignificant.
And the goverment pays ? Who pays them ? Not even a question a sensible person should ask.

"By condemning older homes and building new super efficient ones in their place we can reduce overall US energy consumption(~20% of energy demand~20 quads) tremendously."

Does this take into account the life cycle of the energy needed to make all the needed materials Copper, steel, lumber, plastics, etc. next to the demolition and landfilling of the existing structures?

Life cycle energy cost analysis is not easy because of the indirect energy of producing the materials and transporting them to the site, along with transporting workers.

If you calculated the weight of fuel a typical house consumes, including the coal and gas used to generate the electricity, you may be surprised at the amount. I’ve seen this expressed as carbon emissions.

Conventional houses do have rather short lives. Something made of AAC, like I designed and built, 200 tons, will probably last for 500 to 1000 years. I know it will last that long because that’s how I designed it. Best of all, it needs practically no maintenance. I even went so far as to run the plastic water supply lines in electrical conduit, so standing in the mechanical room you can pull a new piece of tubing through and replace it in 15 minutes. That way no one will ever have to jackhammer the slab.

I stayed at a hotel room in France that was formerly a castle guard house, 900 years old. There are several very old homes in Rottenburg, Germany, and elsewhere around Europe.

I am working on an article now on the retrofitting my 75+ year old farm house (30 ft x 30 ft 2 story + basement) with R50 wall insulation. Current house has clay tile structural wall with brick facing on outside and lathe&plaster on inside - NO insulation. This construction has R3 value per my Handbook of Mathematics from the 60's.
Hope to have article done in 2-4 weeks. Insulation retrofit this Spring.

Hi Jon,

I don't know anything about your local climate, but is there that much to be gained going from R20 or R25, say, to R50? I'm guessing you have roughly 1,700 sq. ft. of wall area after subtracting various windows and doors, and if you live in an area of 5,000 HDDs, at R25, your wall losses would be approximately 2,400 kWh/yr, so moving to R50 would theoretically reduce your heat loss by about 1,200 kWh/yr (~ 35 U.S. gallons if you heat with oil or perhaps 50 gallons in the case of propane).

I upgraded my walls from R6 to R22.5 by re-insulating and extending the walls inward by two inches, and the economics at that were somewhat marginal, even at 7,800 HDD (granted, my cost per kWh of heat is effectively $0.04 CDN, so the optimal amount of insulation in my case is toward the lower end of the band). I take it to achieve that level of performance, your walls will be a foot or more deep?

Cheers,
Paul

The current masonry wall is about 12" thick. I will be putting up a new 2x8 stud wall and spraying 7+ inches of R7 per inch foam and then covering that with plywood/OSB (oriented strand board) and new metal siding.
The labor to put up the stud wall, plywood and siding would be the same for 2x4 or 2x8. The additional cost for the 2x8 over 2x4 or 2x6 is minimal in the total job cost. The only real difference is in the cost of the foam.
Considering that I am only going to get one shot at this (I can't come back later and just add some more insulation if I find I need it) I will go the whole R50.
My hope is to get to a low enough energy loss rate than I can heat the house entirely with active solar with water storage. My preliminary figures say it can be done here in central Minnesota - Heat Degree Days at 8400 approximately. Based on average 8 sunny days per month in the winter.
Energy cost have more than trippled in the last 5 years. ($0.58 to $2.32 per gallon of propane) I expect the future cost increases to be even more brutal, therefore the extra investment to save energy by going R50 will pay for itself easily over the next 10 15 years (in my opinion).
Basing insulation investments on current energy costs instead of trying to base them on your best estimate of future costs is short sighted in my opinion.

Hi Jon,

Thanks for the additional info -- it does help fill in the gaps. Can you tell me, roughly, what it will cost to build this wall system, per square foot?

And I do agree that future, not current or historical cost, is a more appropriate gage, but neither is 100% fool-proof. Earlier this summer, I made some investment decisions based on heating oil then priced at $1.42 a litre ($5.38/gallon) and today it's selling for less than half that.

Cheers,
Paul

Are you putting the insulation and sheathing on the outside? If so, you'll have an immense amount of beneficial thermal storage mass working for you on the inside. Thermal mass outside of insulation has little to no beneficial effect.

Thermal mass on the outside can be VERY useful. On a day when Phoenix has a high of 96 F and a low of 62 F would be an example.

Alan

Yes, in areas where the temperature swing is around the comfort zone, then thermal mass on the outside can be beneficial. I was focusing my answer on Halifax.

My McMansion is a wonderful solar collector in July and August. Unfortunately I live in central Texas and must mechanically pump the excess heat out.

... i think i need awnings ...

The condo complex I lived in last year has no awnings or overhangs on the south-facing sides.  The entry doors all have storm doors and were painted black; they would become hot enough to burn flesh on summer days.

Of course, the condo association would not let people install awnings to reduce the heat load.

It would have been relatively simple to install overhangs with solar thermal collectors on them for DHW.  I doubt that this will ever be done; though the condo association did take up my suggestion to switch the porch lights to CFs, such investments were beyond a body dealing with multiple units in foreclosure and not paying association fees.

Per single home vs. multi-unit building, I live in a 31 unit condo building built in 1929 (so this building is definitely not an energy efficient design) It has the typical huge single boiler with steam heat to all units. Our annual natural gas bill (boiler was originally coal-fired) is about $50,000. Divided by 31 units that works out to $134 a month/unit over the year which, I believe, is substantially more than what the owner of a single family home in the Chicago area could expect to pay for a similar floor area.

As to doing something to improve the energy efficiency of such a building as this - ha! I would love to have an individual heat source over which I had control but all I can do currently is turn off radiators. Sometimes we even open windows in winter. Until three years ago there was a single outdoor sensor that determined when the building boiler would go on. The association put in a multi-sensor system in selected units that vote to turn on the boiler. No significant savings in gas use has been noted - though I believe this may be because the condo board members live in top floor cold units and call the building manager for heat, over-riding the sensors.

We are in a unit that has a unit above, below and to either side. We get through winters with all but the bathroom radiators off unless the temp outside gets below 30F, so we are subsidizing those on the third floor with a northern exposure who say they are too cold even with all of their radiators on.

Short of demolition of this building, I don't know of much that can be done and I'm sure many a resident of an old multi-unit building could tell the same tale. Perhaps all residents should go in on funding the insulation of the northern exposure units, since those units drive the heat demand. I doubt that would go anywhere since $134 a month year 'round is manageable.

Does anyone know of a source of ideas for old buildings?

Hi CB,

Have you considered installing thermostat controls on individual rads, so that you don't have to rely on those so called "New York thermostats", aka "open windows"?

See: http://www.thisoldhouse.com/toh/video/0,,1638722,00.html

Cheers,
Paul

I suspect the largest problem with adding external insulation is making it look nice.
There are several commercial systems for adding a few inches of insulation to manny kinds of houses, I expect a lot of them comes from Germany. And its the same with well insulated windows,
its hard to make them as charming as old windows. Manny renovated apartents and offices in Sweden keep almost century old double pane windows since they look nice and the hand selected window frame wood last forever if maintained. But there are some alternatives for fitting heat retaining glasing in old window frames.

Steam heat sounds odd for me. That is a technoly that were abondoned in Sweden in the early 1900:s. Small scale natural circulation systems were cheaper for small houses. And it is easier to design and control a system where you pump water around making it a standard for both engineered and cludged togeather systems. The district steam systems are very few and all of them are as far as I know for industrial customers.

Where this house situated over here I guess the old steam system would be ripped out and replaced with hot water system and individual thermostates in the apartments. When is it worn out?

I have not seen any collection of ideas in english but I can add to your frustration by assuring that it is a solvable problem, at least if is ok to make the house uglier with flat featureless walls and recessed windows.

Hi MR,

Replacing those old cast iron radiators, installing the additional plumbing lines required to accommodate a hot water based system and a new commercial size gas boiler is likely to be cost prohibitive. Assuming each unit is individually metered and provided there's sufficient panel capacity, another option would be a through the wall heat pump or a floor mount ductless unit. This would provide fully independent heating and cooling and, at the same time, eliminate any unsightly window a/c units.

See: http://www.friedrich.com/products/LineModels.php?line=FCU

Individual temperature controls would greatly enhance occupant comfort and eliminate needless waste, particularly on days when the north face units could use a little extra heat (or, conversely, the south and west facing units additional cooling), plus you have the benefit of only paying for what you use.

Edit: If individual ductless or through the wall units aren't feasible (e.g., inadequate wiring or bulk metering), another alternative might be a central system such as Mitsubishi's City Multi. These systems offer simultaneous heating and cooling (in effect, they can remove excess heat from one unit and forward it to another where it is needed, rather than simply rejecting it outdoors, an especially useful feature during the swing seasons). In this case, you have one or more rooftop units (see: http://www.mehvac.com/Products/subCategory.asp?ProductCategoryID=5&Produ...) that supply heat and coolth to a network of independently controlled indoor air handlers and, if you so wish, you can use its metering capabilities to bill each tenant the exact portion of energy used.

See: http://www.mehvac.com/caseStudies/PDFs/BellaMira.pdf

Cheers,
Paul

But there are some alternatives for fitting heat retaining glasing in old window frames.

Could you provide a link ?

Local Green building group is not aware of any.

Current project with 10 pane cypress windows. (Cost of custom replacement around $500).

Thanks,

Alan

Alan;
I've seen double and triple-pane inserts for typical divided light wooden windows, but as the glass-dividing frame is usually (?) aluminum, I'd be reluctant to create a system with all that thermal bridging(including the wooden-muntins as thermal bridges, too), energy-intense materials and cost in general. Would they be willing to add interior or exterior glazing over the full expanse, and simply re-glaze the individual panes normally?

In your climate, of course, it must be done with particular care to manage the humidity, so that the wooden parts and the glass surfaces aren't constantly inundated with condensation.. but even if it's more labor-intensive or craft dependent, I'm sure there's a way to do that which is not as dollar-and-material-intensive, whether or not it ends up being your group's preferred direction.. (assuming also that there are some volunteers around to offer up the labor portion)

Bob

I found an example via searching on a swedish do-it-yourself board.

Its an all swedish site but the pictures shows how it works:
A verison that replaces a pane in a wooden framed window:
http://www.mistralfonster.se/htm/produkter_thermo.htm
http://www.mistralfonster.se/htm/produkter_thermo2.htm

Another version that is glued onto the old window:
http://www.mistralfonster.se/htm/produkter_iso2.htm

They also got single pane glass with IR-reflective layer.

I have no information about the quality and lifelenght.

Thanks !

Any link for single pane IR glass ?

Alan

Is there a formula for sq ft of Aperature per cubic ft of dwelling .... Maybe Nick Pine knows ??

Anyway ... for 1200 sq ft of dwelling, I have 8 x 60' =480 sq ft of potential Aperature to gather solar thermal energy

The Nick Pine Simple Trombe Wall

http://www.builditsolar.com/Projects/SpaceHeating/nicksthrombe.htm

or solar closet

http://www.ece.vill.edu/~nick/solar/solar.html

is the best aperature for the money .. anyone know of a better one ?

I have sent a couple of eMails to Dr. Wolfgang Feist about applicable standards fopr New Orleans.

Heating, the primary focus of Passiv Haus, isw of minimal concern in New Orleans (my Weatherbug tells me it is 68 F there now, at 6:29 PM, lthough I am in Baltimore ATM).

Humidity control in the summer is the biggest single issue, and one their standards are ill equipped to deal with. Although they are looking at it.

I want to build one in a couple of years, but a new paradigm is needed for Passiv Haus.

Best Hopes for Humidity Control,

Alan

Alan,

I live in the Mobile area. A well insulated house does not require much heat in this climate. My neighbors had to put a porch on the south side to keep out the summer sun. Otherwise they had to run the air conditioner on clear winter days.

You can still do passive solar, but I recommend it at a minimum. You will need a large overhang ( 5 or 6 feet) and a window that goes low to the floor, but these dimensions just for illustration and you need to do calculations for precision.

Unless you have shade, a good design is a ranch oriented longest dimension facing south. For two story, use porches east and west, typical old southern architecture. For south side windows that will not be used for passive heat, you need about 30" overhand for windows that have bottoms 3 ft above floor. This will keep out summer sun.
Have all cracks sealed with foam to keep out humidity. This includes behind baseboards and moldings, and around electrical boxes. And have the smallest size air conditioner that will do the job. Insist that the HVAC contractor run calculations and not guess. The AC needs a long run time to remove humidity.

Good luck

Thanks. I do my own Manual Js, and have designed HVAC for commercial buildings.

A house built to Passiv Haus standards would not need any heat at all (solar or other wise) for 355+ days/year in New Orleans. People, energy efficient lighting, computers, TVs, cooking, etc. will be more than enough.

"Small units' are good, but not enough. They vary in humidity control. And the fresh air requirements will import humidity (Passiv Haus likes more air exchanges, "controlled" leaks). My ASHRAE approved solution is a CO2 monitor that only adds fresh air when XO2 builds up (an approach Passiv Hasu has not accepted).

The Germans have just not gotten their heads around New Orleans (and Mobile) climate.

ALan

Totally agree that Passiv Haus standards do not suit humid subtropical climates. We need to develop our own.

At a minimum there need to be standards by latitude: northern, mid and tropical. These should deal with the sun angles encountered. Standards are also needed for humidity regions too.

Also, standard building codes do not adequately address construction materials and methods by region. I do not think any kind of wood construction is desirable in the humid subtropics. Termites have eaten up most of the older houses in this climate, except the cedar and cypress. Cypress and cedar are depleted and too expensive. Treated lumber will work well, but by the time you figure the cost of treated lumber and the reinforcing to meet hurricane wind loads, concrete is the best option.

Roofing is another issue. Metal, particularly aluminum, is much longer lasting than asphalt shingles. Metal roofs can be painted with newly developed coatings that reflect heat. Aluminum can last 100 years or more and can be efficiently recycled. Tiles are also durable, the main disadvantage is that they are heavy.

Concrete is the best option

Concrete brings with it high soil loading# and LOTS of thermal mass. Neither good in New Orleans. Plus it tends to be ugly.

Robert's new accoya treated wood is interesting.

Cedar is inferior to cypress, but still available and is a common substitute for repairs, etc.

Interesting about aluminum roofs.

# Some work has been done with concrete poured over Styrofoam, to reduce soil loadings. Otherwise pilings are the other solution. except for a narrow sliver along the river (larger particles accumulated there over millennium of spring floods).

I am inclined towards steel stud construction with treated plywood facing (cedar or "Hardiwood" (cementious fiber) siding on top of the plywood). Perhaps 8" vertical steel studs with 4" horizontal studs, 2' spacing on inside horizontal studs).

Even in areas that did not flood during Katrina, the first 3' elevation cannot be used for habitation, which is a handicap for concrete construction. Traditionally homes were raised in New Orleans, but not our post-WW II suburbs.

Alan

Concrete brings with it high soil loading# and LOTS of thermal mass.

The former I can see is a problem. The latter can be of benefit if inside the insulating shell, as night-time A/C will cost less and the thermal mass can help moderate daytime highs. Ice chillers work on a similar concept, though using phase change vs. sensible storage.

I installed a couple of CO2 monitors. A couple of hundred dollars for the base unit plus skilled labor for simple link to controls (even simple stuff costs $$ with good skilled labor).

VERY good way to get around absurdly high ventilation requirements of ASHRAE. (I noted that make-up air NEVER came on during windy days. Too much air injected naturally, so ANY mechanical injection of air would have been a waste of energy).

I also ran make-up air through dehumidifier before injecting into building. Inject cool, dry air during most of year.

In a home, good safety back-up for tight home with gas stove or gas space heaters.

Best Hopes for Intelligent Design,

Alan

Alan,

Forgot to mention that I located the gas furnace and water heater in a mechanical room that in the center of the house. The mechanical room with door closed does not draw air from the interior of the house, but through air make up ducts to the attic. The mechanical room walls are aerated concrete, so it is insulated from living space, and fireproof. I also have an electric cook range and oven.

This greatly lessens the air make up requirements and associated humidity problem. I don't know if the Passive House standards address this.

Paasive Houses don't use furnaces(central heating) at all--in fact it is the major selling point.

They might have a couple pieces of baseboard in the bedrooms or just use portable electric heat for emergency/code required heating.

To meet the standard you are encouraged to use evacuated tube solar panels along with electric/gas point-of-use hot water heaters. Lots of gas appliances like gas clothes dryers will cause you to fail the primary energy requirement.

You don't need a fire rating if there are no gas appliances in the mechanical closet. In most US building codes you don't need a fire rating in a residence or a storage room under 100 sf in commercial.

Combustion air would put the building under negative pressure--a big no-no.
All ducts bringing in outside air must be heavily insulated. Chimneys are out.

There is no point in insulating the boiler room walls unless it would be for soundproofing which isn't necessary with no central furnace. All the insulation is on the outside walls.

Humdity problems in a Passive Home is solved by using a continuous running energy recovery ventilator. Wretched excess like hot tubs and saunas are out.

Humidity problems in a Passive Home is solved by using a continuous running energy recovery ventilator

Useless when the outside temperature is 95 F / 35 C and the relative humidity is 90%.

Outdoor mounted tankless whole house gas hot water heaters located close to the kitchen and bathroom use little more gas to heat water (a little stranded in the lines) but the only penetration required is for the hot water line.

Alan

Useless when the outside temperature is 95 F / 35 C and the relative humidity is 90%.

That's not design data for New Orleans 95 db/80 wb ~ 55% rh.(35db/27wb C)
In fact I don't know anywhere on the planet it is so wet.
That's equal to a wet bulb of 92 degrees on a special psych chart. The hottest climate I've seen is DaNang, VietNam at 97db/86wbF (36db/30wb) which is ~75% rh.
I suspect that you are exaggerating.

The Passive House usually has split system AC for cooling and the Passive House quality enthaphy wheel ERVs are +90% effective total heat and in addition for tropical climates a separate dehumidifier will need to be provided.

Gas fired tankless water heaters are an incredible extravagence. They produce far too much hot water and frankly somewhat dangerous. How would they work in conjunction with solar hot water systems? While a tank gas hot water heater rates as 58% efficient, aninstantaneous HWH rates as a 82% in DOE water heater tests but they provide far too much hot water for a Passive House family; the tiny Takagi TKJr is 111000 Btu! Europeans use far less than half the water per day that Americans do. I don't think you could live 'large'
American style in a house that meets the standard for primary energy use.

The Passive House folks like heat pump water heaters or point-of-use electric.

Also an outside water heater might be questionable in Northern Minnesota.

What if you are gone during the day and allow the home to heat up ? And then turn the a/c on when you return (or automatically on 20 minutes before usual return time) ?

This approach works MUCH better with almost zero thermal mass inside the insulation. And it is more energy efficient.

And Time of Day pricing is not yet common. Even if it was, I suspect my cooling bill would be lower with "as needed" cooling.

Alan

Totally agree that Passiv Haus standards do not suit humid subtropical climates. We need to develop our own.

Something to consider in terms of climate change: homes currently in one zone might well be in another in 50 - 100+ years. Might be useful to consider engineering for an adaptable design.

Cheers

The CO2 monitor is a great idea. Germans have a tendency to over-engineer, so I am surprised Herr Feist would object. Perhaps they are aiming for an aesthetic of simplicity. The monitored air exchange plus a very small AC would probably work well in humid climates, not just the Gulf coast, but also places like the Midwest and East in the summer. Personally, I would not aim for Passivhaus cerification, just adapt the philosophy to the local conditions and take advantages of their tools for calculating insulation requirements. I bet also that in New Orleans you would not need the triple insulated window and the really thick doors that passive houses have in Germany and which are quite expensive.

Alan - Are there commercial buildings that currently use CO2 monitors as inputs for ventilation systems controls? Any idea if anyone has a CO2 monitor that would be cost effective for home Heat Recovery Ventilators?

Kevin

I replied to wrong comment. See above. Alan

.

Hi Kevin,

In answer to your first question, see: http://www1.eere.energy.gov/femp/pdfs/fta_co2.pdf, http://www.oregon.gov/ENERGY/CONS/BUS/DCV/DCVcasestudies.shtml and http://www.p2000.umich.edu/energy_conservation/ec3.htm.

In residential applications, proper humidity control, cooking odours and VOCs (i.e., off-gassing of paints, carpets, varnishes, pressed wood binders, adhesives, caulking materials, etc.) are more critical concerns.

Cheers,
Paul

The Germans have just not gotten their heads around New Orleans (and Mobile) climate.

Why should they?  They "scratched their own itch", not yours.  They don't know what you need as well as you do.

A house built to Passiv Haus standards would not need any heat at all (solar or other wise) for 355+ days/year in New Orleans.

But it can use dehumidification for most of that time.

Perhaps the humid zones of the world need to push some research into e.g. solar-powered, dessicant-based dehumidifiers.  If the heat supply can be combined with the DHW system it would reduce the installation costs; there's probably less need for DHW when dehumidification is required, so less capital cost overall too.

Nice series, thanks.

It's interesting to see how history repeats, maybe because teh same laws of physics apply.

Although with much more modern technology, Passive Houses have some interesting similarities with Frank Lloyd Wright's 1930s *Usonian* houses - see page 14-15 of this paper, for example.

Unlike FLW's expensive spectaculars like "Falling Water", Usonians were designed for moderate cost. They used glass wall/heat mass (often concrete block walls) effects, and "interesting" radiant heat systems embedded in concrete floors. We have a 50-year-old expanded Usonian done by one of FLW's students, and it works pretty well, although it doesn't have radiant heat.

The tough problem is the old single-pane, floor-to-ceiling glass, but we put Hunter-Douglas Architella blinds (double honeycomb with metal foil, claiming R-value ~7) on the big windows, and that really helped.

The heat mass / concrete block walls work fairly well here, given that we have warm day / cool night / low humidity climate.

Similar ideas (partly inspired by FLW) were used by Joseph Eichler in building large numbers of homes in California in the 1950s and 1960s. These are "love them or hate them" houses, of which there are many around here. I used to have one in Palo Alto - the insulation wasn't up to less milder climates, but it made very good use of space, and the indoors/outdoors combination was quite pleasant.

Food for thought. What color do you want your house and roof to be in the summer, and what color in the winter? Obviously, black would be best in the winter and white in the summer.

It would seem our technology has come far enough that a chemist somewhere could come up with a coating that was temperature sensitive. Turns black when cold and white when hot.

Let's leave esthetics out of the discussion:)

Black does not only absorb heat faster, it also radiates it faster. So the answer would be white in most cases (or green from plants, which also help insulate).

Black does not only absorb heat faster, it also radiates it faster.

No. Ordinary paints that are black and white in the visible spectrum have the same emissivity at the thermal wavelengths relevant to this discussion. Objects painted white radiate at thermal wavelengths just as well as objects painted black.

Damnit, another failure of high school physics. :(

Thanks for setting me straight. I had no idea; I always assumed emissivity was approx equal to 'absorptivity'.

It is... at any particular wavelength (otherwise you can create a Second Law violation).  The kicker is that the incoming radiation is at 5700 K radiation temperature and the outgoing is perhaps a tenth of that or less, so you're working in two very different wavelength bands.  That's why selective radiation surfaces are worthwhile.

My sister is selling her apartment and returning to the states with a cash to live off of in her retirement. She is a widow with no children and has little need for space. She asked me to find a two "family" house for her and me and my wife. We have 4-10 more years in the work force.

I am an architect, not working as one, but in the stone industry, the victim of the "economy". I am not LEEDS certified and probably won't bother because I am not practicing.

I suggested that we build a green energy efficient passive design perhaps with solar PV and water heating. She loved the idea so I at the beginning of this effort and looking for support and consultants.

Cutting wood for a stove will not be an option. We want a lot which is close to public transport in southern Westchester Co, NY. Buildable lots which meet this criteria are hard to find. Being close to a village center means we can walk to get the things we need to live and not have to depend on a car.

Now the issue is one of zoning and passing architectural review boards. The latter are very concerned about the "look" of the neighborhood and don't want a home which looks odd and lowers the property values. This is a matter of "conformity" to maintain some illusion of property values. Of course you can build a snazzier looking house, but never an odd one or a cheapy looking one.

To complicate this the zoning issue of two kitchens mean two families. I know my sister wants some independence and privacy and assumed her "unit" would include a separate kitchen. The number of kitchens defines the number of families in some jurisdictions (despite that orthodox jews have two kitchens in their homes).

Now if we can get past the above barriers we need to find a relatively small "village/suburban lot) with enough solar exposure and "privacy" which can work. Only then can we move into the design.

And finally we are facing very high asking prices for building lots. I am trying to figure the "new price:" point as rela estate is dropping fast. And there is very little building going on because of the credit crunch. We think we should be ol with credit, but I haven't figured out what the "real value" of a lot is in this market.. I suspect the lots we like for sale will be owned by a neighbor who bought it many years ago for "protection" and breathing space, but now wants to get some cash and has unrealistic expectations of its worth.

What is land worth?

When you calculate your energy footprint do you also consider your CAR if you need it to get "things" and get places? We could solve lots of the above if we moved away from public transport - cheaper land, lower taxes, more sun exposures, no arch review boards or restrictive zoning.... but it would cost us more in other ways/

Your thoughts.

To complicate this the zoning issue of two kitchens mean two families.

Frequently, jurisdictions have exceptions for "Mother-in-law apartments" that are attached in some manner to the house, often over a garage, in a basement, etc. I would see that as the first place to look.

Public transport can come in different forms; subway, light rail, and bus. Being away from the first two does not mean the third is also out of reach in many places. See Westchester County Bus System Map.

Land near existing or planned bike paths/lanes means one doesn't always have to be within walking distance. Connectivity of bike trails to mass transit helps one understand the locations that might be currently underpriced for a high oil price future. Westchester Bike Trail Map

Each building lot would require its own site survey to determine potential shading effects from trees and other buildings.

If two kitchens are a problem, delete one from plans but "engineer" plumbing and electrical for easy add-on. After final inspection, and occupancy, do some weekend work.

Best Hopes for Higher Density Housing,

Alan

That's great! Unfortunately most of the world lives in conditions such as this. I took this picture in Sao Paulo Brazil a couple of years ago... It's very energy efficient housing, trust me.

Affordable housing

Here's a more realistic approach to future housing.

http://www.n55.dk/MANUALS/SNAIL_SHELL_SYSTEM/SSS.html

A polyethylene tank, huh?

I'm almost there. Much of the time lately, I live in 'The Oil Drum'. Portable, Spacious-yet-claustrophobic, bright-but-cloistered.

Perfect!
Bob

A polyethylene tank, huh?

Yeah, it's each person's lifetime allotment of products derived from petroleum, better use it wisely ;-)

Somewhat related to our renovate for efficiency versus tear down and build anew debate:

http://www.buildinggreen.com/live/index.cfm/2008/9/2/Lies-Damn-Lies-and-...

Cheers,
Paul

Thanks for mentioning this!

http://www.buildinggreen.com/live/index.cfm/2008/9/2/Lies-Damn-Lies-and-...

I really wish I had make this point about the popular LEEDS standard
more strongly. There is a very real danger of greenwashing in future construction.
The Passive House Standard is by far the most energy efficient standard but the architectural community politicians in the US are solidly backing the inferior LEEDS standard, complete with extravagant 'energy efficient' heating and cooling systems that continue to waste energy.

I came to much the same conclusion. LEED is "nice" (better than nothing) but simply NOT enough ! Passiv Haus is real, and good, but not flexiable enough yet (a German trait ?)

Alan

You are correct about the Passive House Standard being difficult to meet in New Orleans (or Florida or South Texas) due to severe humidity. Typically a separate dehumidifier is required.

The PHPP form presently does'nt have a entry space for PV solar electricity for dehumidifier power.
The US DOE zero-energy standard(70% efficient) does allow rooftop PV to be included.

The Passive House people are looking for a mechanical system solution on this.
One idea is that a 'compact' heat pump could be developed to simultaneously dehumidify, heat domestic waste, dry clothes, etc. and that appliance could help meet the standard. Small ground source heat pumps might help. About 15 years ago DOE was working on a 'dual' heat pump that produced domestic hot water as well as cooling but the HVAC industry didn't pursue it.

Hi majorian,

The fact that a building can be awarded LEED points on the basis that it utilizes LED lighting raised a huge red flag in my mind.

Rant Mode: On

I don't want to continually bash LEDs, but Cree is one of the leaders in this field and they recently introduced their LR24 fixture which is, arguably, representative of the state of the art (see: http://www.creells.com/lr24.htm). I believe these fixtures retail for a mind popping US$380.00 each and the U.S. Pentagon has just bought over 4,200 of them (see: http://www.creells.com/PressRelease.aspx?ID=33). Part of the current economic stimulus plan, I trust?

In any event, this fixture produces 3,200 lumens and consumes a total of 48-watts, which works out to be just under 67 lumens per watt. The life span **IF** you can maintain a fixture temperature of no more than 35C (and if you can pull that off, then I've just witnessed the second coming of Christ) is 50,000 hours, at which point its light output has fallen to just under 47 LPW.

For about one-fifth this cost, they could have chosen Lithonia's 2RT5 recessed fixture which utilizes two T5 fluorescent lamps and offers either full or step dimming. This fixture has a luminaire efficacy rating of just over 80 lumens per watt (see: http://www.acuitybrandslighting.com/Library/LL/documents/specsheets/2RT5...) and its lamps will happily operate at temperatures as high as 70C. In the case of a conventional Philips lamp, rated lamp life at 12 hours per start is 35,000 hours -- eleven years at 60 hours per week -- and lumen maintenance at EOL is 95%. If, however, you require something a little longer and don't mind trading off a little lamp efficacy in the process, Kumho's Sequoia T5 line offers up to 100,000 hours -- 32 years at 60 hours per week (see: http://www.kumhoelectric.com/downloads/spec_sequoia.pdf).

Now, ask me why I'm so damn cynical.

Rant Mode: Off

Cheers,
Paul

I would like to see 'practical' LED ( aka Xmas lights) but they ARE rather weird and I don't see a lot of them.

I personally don't like blindingly brilliant linear T5's. They are typically indirect lights which are nice in certain(commercial) settings. Most home lights are compact fluorescent lamps and now we have nice compact fluorescent track lighting. Of course rather than garishly lighting up our homes like jewelry stores with dozens of halogen can lights we should probably simply use more CFL task lighting.
At least that is the probable reaction of the Passive House folks.

Have you seen the 'superT8' linear T8s. These are my own favorites. Slightly less bright than wonderfully efficient
F32T8(at 28 watts!).
The Passive House standard relies on lighting as an internal heat source and with CFLs it is rather low watts/sq. ft. anyways.

But lighting technology is evolving very quickly and it's hard for me to pick a 'winner' yet.

Hi majorian,

These fluorescent fixtures are attractive (comparatively speaking) and provide excellent, low-glare light with exceptionally good coverage and they're also very energy efficient (obviously, more suited for commercial and institutional environments than residential applications).

See: http://www.lithonia.com/rt5/photogallery/Gallery.asp

With respect to the high performance or "super" T8s, my firm installs between 50,000 and 100,000 of them each year, mostly 5,000K Osram Sylvania XPS.

Cheers,
Paul

Some personal experience to share. Own an old farm house in the upper midwest. The original structure is approx. 125 yrs. old. It has an addition of the same size as the original which is approx. 75 yrs. old. Total of 1800 sq. ft - considered a 1 1/2 story. When we bought the house there was no insulation. The single pane windows were so old the glass was wavy with bubbles in it. We bought it because the price was right, on 5 acres, 6 miles from our jobs. We installed a wood stove for whole house heating right away. Would rountinely burn 18 - 20 cords of firewood a season. Began planting trees immediately, deciduous on east and south sides, evergreen on north and west.Lots of fruit and nut trees in between. The house was not situated east/west for passive solar. After much thought, came up with a floor plan that would take advantage of passive solar. Put the majority of money into insulation and windows. Ran a covered porch along the south side, put a small woodstove in the livingroom. We burn 5-8 cords a season now. Have no AC, only ceiling fans. The inside of the house is usually 10-15 degrees cooler in summer. On sunny winter days we let the fire go out - to warm in the house. We have no thermal mass other than the masonary block for the basement. No solar panels, no central fan system. The entire remodel was less than $50,000.00. We bought the house and 5 acres for $35,000.00 12 yrs. ago. We put a lot of sweat equity into it, used local and salvaged materials whenever possible. Did bargin shopping on EBay. Didn't compromise comfort or convenience, have modern energy efficient appliances and decor. It's a place where we can grow old and still be able to maintain it.
So it is possible to retro-fit older homes, even in cold, snowy places without costing a fortune. Just takes thought, planning and some sweat.

For humidity .......develop a solar still to remove water and save it

http://groups.yahoo.com/group/LittleHouses/photos/album/922983239/pic/14...

SAVE water ? In New Orleans ??

I live less than a mile from the Mississippi River. Average over 60" of rain/year.

First glance, too small to have an effect.

Alan

okay .. forget saving water in your area.

What is too small to have an effect?

Distilled reclaimed water with no transportation costs may still be of value in N.O.; if I was there and had an A/C unit running, I'd probably save the condensate for flushing the toilets or something.

I have not had a chance to read all the comments, so apologies if this is a duplicate, but I would simply observe that the problem with this analysis is that it comes too late - how many of us will be building houses in the middle of our credit crisis? We now have poorly made housing stock that exceeds our broadest requirements by 1-5 million houses - and we won't be needing the outside numbers in the US, as people consolidate because it is the only way they can afford housing.

Meanwhile, passivehaus retrofits cost 50-80K, - and who will be taking that money out of their non-existant equity.

Don't get me wrong, I'd love to have seen passivehaus design be integrated into American housing, but this is one tool that I think has absolutley no hope of actually being widely applied for the forseeable future.

Sharon

But anyone can pile mud up between a couple pieces of plywood!

Oh, and something I should have mentioned before: wrapping an existing structure in straw bales has been done.

Cheers

I'm trying to figure where our home is in comparision? Our home is in Syracuse, NY area. Built in 1990 and I've upgraded insulation and reduced air inflitration. Programable t-stat. Changed out incan. light bulbs. Added storm doors and vestibules.
1,000 SF footprint. 2 story = 2,000 SF living area plus full basement of same foot print.
Grid purchased "Wind and small hydro" electricity. (Whatever that is worth?) About 9,000 KWhr per year electric.
Heat home and hot water with Nat. Gas at about 900 therm per year. What is that in KWhr per meter squared?
I'm not sure what else I could do for this house that I'm willing to pay for!
I've looked into solar HW and PV electric but don't have the south exposure and with Lake Ontario cloud cover is a problem.
The hot water system if it displaced my HW needs 100% would have saved me about $35 a month. I was told it would not save 100%, however.
I've been told my house would not qualify for NYSERDA money. South exposure is a problem. Neighbors tall trees to east and south. I've was told by a PV installer a PV array of 3 KW would yeild 3,000 KWhr per year or about $500/ yr at $0.17/ KWhr. Sounds like he fiqures about 1,000 hours of production. Just thinking!

The US Gov't. published a report called something like "Energy Consumption of the Typical American House". I've seen it on the internet, but it would be a little outdated now, as I think it was done around 1990.

Perhaps they have an update.

Many utilities have web sites where you can enter data on your home and have it compared to averages. Here is the one in my area, which of course will give incorrect comparisons for your area.

http://www.alabamapower.com/residential/checkup.asp

Here's another I haven't used:

http://hes.lbl.gov/

3 things to consider: adding a layer of laminated glass to your windows; a tankless water heater; and an air-source heat pump.