Forgotten Pioneers of Energy Efficiency

Scanning the Horizon
by Grant Dorris

"Some U.S. builders look expectantly to research labs, hoping that technical breakthroughs will help get us through the next energy crisis. While such hopes are understandable, they show little understanding of history.

To design and build extremely energy-efficient houses, no new technical breakthroughs are required. We’ve hardly begun to deploy the simple lessons learned 30 years ago; so why are we still scanning the horizon for new whiz-bang inventions?"

While reading a post on this site, I learned that 80% of all homes are built by 20% of all builders. This means that the same small percentage of builders keep repeating the same [energy efficiency] mistakes over and over. Having worked for many of these 20% of all builders (production builders), I can honestly say that I do not think they care about the past, present or future of energy efficiency.

Sure, I know some that want to do the bare minimum to get an Energy Star rating for use in marketing - but that did not occur until the last year, or so, when sales plummeted. I know that if most production builders put 1/10 the time into building for energy efficiency that they put into cutting corners and maximizing profit, it would mean that hell froze over.

On the other side of that coin, the consumer needs to know what to demand and expect from builders - and their homes. The consumer needs to not be distracted by amenities and fancy trim, but rather the performance of the home they wish to buy. I believe that consumer demand would help reshape available product.

When I scan the horizon, I see the need for education and applied building science over technological innovation.

The Consumer Doesn't Have a Choice
by Andrew Henry

I agree with the tone of Grant Morris's comment.

That said I don't actuallly think that the consumer has much choice.

The large housing developers control much of the land for new construction. And they dictate what gets built on it, with a small catalog of home designs that never took into consideration any meaningful attempts to be energy efficient.

At the end of the day, having watched many of my colleagues recently buy a house, they end up buying a house the way they buy a car. They might give a little thought to energy efficiency, but if it's not available on the market, they have no choice but to buy what is available. They certainly don't have the inclination or wherewithal to buy land (if it's available) and go through the whole long and challenging process of building a truly energy efficient (Passive) house themselves.

The large developers have had thirty years to deliver truly energy efficient homes, they couldn't even manage R-2000 on their own and it's been around almost that long. The market has failed to deliver, and only because they chose to serve themselves and not also their clients and society.

Government must mandate energy efficient buildings, and not half measures like Energy Star, it's too late for that.

All that said, having worked as a framing carpenter on production job sites it's going to be a real challenge changing the laissez-faire attitude that permeates through te building industry and leads to the construction of so many poor quality homes.

Governmental involvement
by Martin Holladay

Grant,
You wrote, "I see the need for education and applied building science over technological innovation." We're in agreement. Implementing what we already know is far more important than developing new technology.

Andrew,
I have to agree with you on the need for more stringent energy codes. The problem with the current system is that the people making the decisions on insulation and airtightness — namely, the developers and builders — aren't the ones who pay the energy bills. Therefore they have no incentive to invest in energy measures. Only higher government standards will raise the bar for all new homes, removing the possibility that some builders will gain a competitive advantage by cutting corners on energy performance.

The same problem exists with appliances. In most cities, refrigerators in rental housing are purchased by landlords. Landlords have no incentive to purchase an energy-efficient model, since the tenants pay the electricity bill. The only solution to the problem is for the government to set higher efficiency standards.

Saskatchewan Conservation House
by Wolfgang Feist

Yes, this is one of the early really good examples, I love it - and there are others (like Vagn Koorsgard's 1973 Kopenhagen Zero Energy House already 1973). All these have been steps towards a solution.
What I have always asked: Why were these scientific results not taken earnest? Well, I know some of the answers - because the answers are still valid today. These are not "nice" answers:

- The results were not discussed even in the scientific community. That community preferred to discuss the high-tech-vacuum-super-pcm-pv-fuelcell-cold-fusion-atomic-vaporiser (:-) dreams. Because there is much more money spend for that kind a stuff.
- Lots of architects did not like the solutions, either - at least the loudest ones, and they still try to spread nonsense (like "high costs". poor comfort, not openable windows and all that rubbish. What about looking at the facts first?
- You Americans were just interested in money, money, money ... (ok, not all of you - but a huge majority). Well, you could have seen that there is money to be made on a sustainable path, too. But it's apparently so much easier to speculate with other peoples money, make yourself a lot of money, loose the other peoples money and get awarded for this by taxpayers TARP. Sorry, if that sounds angry. But: The problem was, that real money (that could have been spend for reducing thermal bridge development promising just "4%" real internal interest rate) was not spend for that using the argument that you better spend it for 12% speculative investment.
- Yes, there is some hard work to be done: Really energy efficient homes have to be really well insulated, airtight, need high quality windows, need heat recovery ventilation - it's all not difficult, but it seems to be difficult for those who never gained experience with that. Does education hurt? Well, I am an optimist, there are educational programmes on the way - and these seem to be successful.
- And ... there are those deliberately spreading disinformation (:-). What about spreading such nonsense as "PV is more cost efficient" than slab insulation? Get real guys! No question, there are climates and sites where you might not need slab insulation (like in SF). But: drawing a general conclusion like this is not only misleading - it is disinformation. And these guys even go further: Trying to make fools out of those, who worked and still in the field with a acientific approach.
- Yes, there are those, who think (since 30 yrs) that "we" (who?) are already "good enough". And that we do not need to go to the "extremes" (What is the extreme - using 12 inches of insulation or using 20 barrels of oil-equivalent to heat your homes each year on a heated planet?).
- Yes, there are those, who think efficiency is not the "right solution" and that all of us should better cut back in our so-thought demands; do you really need 3000 ft² homes? I do not want to judge this, I only think, that a demand of 20 barrels equivalent to heat them is way, way to much. And you can not blame China for this. Its not the Chinese (not so far!), it's us. And we use to be the role model for the Chinese (and others).
- Really high efficiency offers a solution for this problem - a tested and proven (records from Saskatch. house for more than 30 yrs, from Kranichstein more than 18 yrs, now some 20.000 examples), an available, an affordable solution. Not nice enough? Offer something better! Contribute to the development. And stop blaming others.

A response to Dr. Feist
by Martin Holladay

In his posted comments, Dr. Feist takes aim at four different groups: (1) the scientific community; (2) Americans in general; (3) those who have said that PV is more cost-effective than sub-slab insulation; and (4) those who build 3,000-square-foot homes. Since he has chosen to post the comments on my blog, I can only assume that some of the comments are directed at me. As it turns out, I belong to some, but not all, of the four categories he identifies.

1. Dr. Feist complains that the results of early experiments with superinsulated houses “were not discussed even in the scientific community.” In fact, they have been. For example, Oak Ridge National Laboratory has organized 11 conferences since 1979 in Clearwater Beach, Florida. Held every three years, the conferences on Thermal Performance of the Exterior Envelopes of Whole Buildings have attracted scientists from around the world, including Belgium, Sweden, Germany, Canada, and the U.S.

During the last three times I attended the conference, I had the pleasure of getting to know Dr. Hartwig Kuenzel, a building scientist at the Fraunhofer Institut Bauphysik in Holzkirchen. Scientists attending these conferences, including Dr. Kuenzel and others from Germany, have presented dozens of papers on every aspect of superinsulation and building envelope performance. Every one of us in the building community who is committed to superinsulation owes these scientists a debt of gratitude for their work; we stand on their shoulders.

I don’t think the scientific community is at fault in any way for the slow adoption by builders of superinsulation techniques. The wonderful thing about science is that the scientific method itself assures us that the procedures of science will always advance the causes of those looking for rational solutions to our problems.

2. Dr. Feist’s second target is Americans in general: “You Americans were just interested in money, money, money ... (ok, not all of you - but a huge majority).”

Probably the best response to this statement is not to respond. I certainly understand the economic and political behavior that led to your conclusion, and I probably share your political beliefs. But the phrasing of this accusation is a little broad.

3. The next group that Dr. Feist takes aim at is a small one; the group apparently includes me and John Straube: “There are those deliberately spreading disinformation (:-). What about spreading such nonsense as ‘PV is more cost efficient’ than slab insulation? Get real guys! No question, there are climates and sites where you might not need slab insulation (like in SF). But: drawing a general conclusion like this is not only misleading - it is disinformation. And these guys even go further: Trying to make fools out of those, who worked and still in the field with a scientific approach.”

First, I recognize that Dr. Feist takes a scientific approach (in spite of his apparent blaming of the scientific community for failing to take proper note of his research.) I have never tried to make a fool of him or his colleagues.

Second, his summary of the issue I raised is a parody of what I actually wrote. I never wrote that “PV is more cost efficient” than sub-slab insulation. Instead, I wrote that after a certain thickness — somewhere in the range of 6 or 8 inches — further investments in sub-slab insulation were more costly than PV.

Third, since Dr. Feist is committed to the scientific approach, I look forward to the time when he is able to address the technical issues I raised with a technical response — something more specific than “Get real guys.”

4. Dr. Feist ridicules those who think we need 3,000-square-foot homes. I heartily agree with his ridicule, but I am surprised to see it expressed as a comment on my blog. My colleague Ned Nisson and I — both former editors of Energy Design Update — have been campaigning in favor of superinsulation techniques for almost 30 years. Nisson founded EDU in 1982; before that, inspired by the Saskatchewan Conservation House, he spent several years organizing superinsulation workshops throughout the U.S. with Harold Orr and William Shurcliff. In 1985, Nisson published The Superinsulated Home Book, a landmark guide.

For 27 years, EDU has consistently reported on the science of superinsulation, air sealing methods, and heat-recovery ventilation. The newsletter has reported on the results of research as well as building techniques, and has argued consistently in favor of smaller homes with much lower energy budgets than those typically built in the U.S.

In other words, Dr. Feist, we’re on your side. At the end of your comments, you conclude, “Not nice enough? Offer something better! Contribute to the development. And stop blaming others.”

I’ll leave it to others to comment on whether your comments are nice enough. However, I feel confident in saying that the work presented by Energy Design Update and GreenBuildingAdvisor has contributed to the development of techniques to build superinsulated houses. And I’m not interested in blaming others for the fact that superinsulation techniques haven’t been more widely adopted. I just want to keep working at building excellent houses, and reporting on advances in building science, and reporting on the successes of the best builders in the world, as I have been trying to do for many years.

'Gospel of Wolfgang'
by Wolfgang Feist

Not going to give a fast response - but will do later. It is always better to reflect on what one is going to say and going to write.
Just one thing: never wanted to ridicule anyone or any group of persons. (Like the 'Gospel ...'-phrase surely does).
What I say: If you want to use 3.000 ft², better take care to use these energy efficient! In your own interest, but also for acting responsibly. That is not a joke.
And, last not least: This is not about "Gospel", it is about science. Glad, that we seem to agree on this, at least.
Saskatchewan was (and still is) a very good example showing the right path. Could we just agree to take this path? No, what we did later was not "good enough". I will never agree in that something is "good enough". There is always a way to do even better.

Gospels
by Anonymous

As an interested onlooker, I was delighted to notice that this slanging match has, so quickly, begun to use the language of faith, or at least religion. The members of the various sects are so busy arguing that theirs is the one true approach that they miss the point entirely. The vast majority around them do not believe at all, or are, at best, agnostic. It is better to do something, albeit imperfect, to reduce the energy consumption of buildings than to give the majority the excuse to do nothing because the 'experts' argue the minutiae of what is optimal. Never was the saying "the best is the enemy of the good" more applicable. Of course what is required is that the average energy consumption of human beings is sustainable but the buildings of the developed world are a good place to start.

It has been my experience that most engineering problems have the shape of an upturned cooking bowl - similar when approached from any angle, steep and difficult to surmount but having an area on the top which is essentially flat but having local, minor undulations. Once you are on the nearly-flat bit you are wasting your time looking for an optimum, or trying even to define an optimum. Your energies are better spent telling other people where the flat bit starts and helping them to get onto it. Arguing, particularly in a public forum, about which bit is ever-so-slightly higher than another is totally unhelpful.

Looking for points of agreement
by Martin Holladay

Dr. Feist,
Of course I agree with you that the Saskatchewan Conservation house is a very good example — that's exactly why I wrote the blog, and exactly why the house inspired Ned Nisson and was featured prominently in EDU's 25th anniversary issue. So it's good to agree.

I'm a little befuddled by your "Gospel" references. (Merry Christmas, by the way.) I even did a search on the GBA Web site for the word "Gospel" — the only relevant hit was a comment on this page by a GBA reader who calls himself "Rick." If someone ridiculed you by using the word "Gospel," it wasn't me.

Moreover, I have been accused of many things in my life — of extremisms of many sorts — but I have never been accused before of saying than American houses are "good enough." I've been ranting and raving for years in favor of small houses, tighter houses, stricter building codes, triple-glazed windows, much thicker insulation, and the use of HRVs. No, Dr. Feist, our houses are not "good enough." I certainly agree with you on that.

Violent Agreement
by Pat Murphy

I find it fascinating to have Martin and Wolfgang exchanging messages on Chirstmas Eve and Christmas day about an article written in April. I find it fascinating that I am reading the same article also on Christmas! I am visiting Portland, OR from my home in Yellow Springs, OH. Tomorrow I will tour the home of Tad Everhart, who just finished a major retrofit of his home to passive house standards.

It's good to count ones blessings on Christmas. Certainly, having Wolfgang Feist and Martin Holladay exchanging comments about the exciting history of the superinsulation movement is one of those blessings. Both have been and are vital contributors to super efficient homes. I would guess there is about 99% agreement. What they provide is very valuable.

seasonal greetings
by Wolfgang Feist

The world is small, Pat. And it is cold in Portland in these months. Hopefully you stay in a warm, comfortable and efficient home. It's nice to hear that there is such a retrofit already in Portland.

May be that controversy is the trick to get the word spread (:-). If that is true, I can offer to go on ... there are lots of allegations of Dr. Straube to be dispelled. But I am sure, that will not make christmas happier. This in mind, lets just leave it to that.

Happy Christmas, all the best for the upcoming year 2010. See you at the 14th Passive House Conference (Dresden). Martin will forgive me this advertisement.

An e-mail from Dr. Feist
by Martin Holladay

On Christmas afternoon, Dr. Feist e-mailed me to let me know that his "Gospel" reference pointed to an article by John Straube posted on the Building Science Corporation Web site:
http://www.buildingscience.com/documents/insights/bsi-026-passivhaus-bec...

I'm grateful to Dr. Feist for his explanation, but I have no reason to respond to his offense over the term. I suggest that Dr. Feist should contact John Straube if he wants to debate any article posted by Straube on a different Web site. In the meantime, I'm happy to discuss GBA reporting and GBA blogs with Dr. Feist here.

Again, I want to make clear that I never ridiculed Dr. Feist by any "Gospel" references.

Building science? Insights?
by Wolfgang Feist

Now you took the opportunity to refer to this piece of scientific reasoning (:-) again. Did not you identify yourself in your first answer so much with this that you even thought you could frame me with an assault on science itself? Is it you or Dr. Straube who defines what science is? Just to make that clear: I do not. Never did, I refer to Karl Popper with respect to this, another shoulder on which we stand. Neither did I create a dogma. Bill Shurcliff did not and Harald Orr did not. Orr just made a dream work in Saskatchewan - and William Shurcliff published it together with really great insights; most established building physicists do not even know about Shurcliff and his great work. Yes, we are standing on these shoulders, never tried to hide this. And there are others: Bernd Steinmüller, Vagn Korsgaard, Bo Adamson, Arne Elmroth, V. Bogoslovski, ... I might have not mentioned some. There has been progress made since, and these concepts now are really successful. It is good to see good science working also in the field - monitored, tried and tested, in practize. With 90% heat recovery rates, not 65. With 0,6ach@50Pa what is not a problem to achieve, proven in the field. And with proper slab insulation, what not at all makes the concept expensive, but helps to make it work. And with lower electricity consumption most will not even think of. So please guys - is that your only choice to ridicule the concept? Now, contradicting your nice article at the beginning of this blog: "overemphasizes efficiency" over what? "whiz-bang inventions"?

Yes, get real: Notice, that efficiency is working. Since >30 yrs in the Saskatchewan conservation house (0,8 ach@50Pa, already 1977). 18 yrs in Kranichstein (0,2ach@50Pa, yes, you do not need that to be so low - but it does not matter, it was a good basis to do really good science with respect to indoor air quality, humidity, radon, VOC). >30.000 yrs together in all the already existing passive houses (which are not expensive palaces of super rich people). So where are the solutions you want to offer which are so good, that you think it is important to start a campaign against passive houses and the folks building these? Yes, not all of them are scientists, so it's sometimes an easy point to make from an smart-alec position. It's important to have these concepts developed to a point one can use these without being a scientist and by just referring to PHPP (which is not at all the "scientific background", but a fair and easy to use inexpensive tool and handbook, not at all misleading, but very much to the point. That is the "secret" of the success. You could be proud to be part of this success!)

Not sure where all the misunderstandings come from
by Martin Holladay

Dear Dr. Feist,
1. No, I am not trying to define science. Nor do I believe that Dr. Straube can define science. Fortunately, the scientific method assures that the truth rises to the top, regardless of my opinions.

2. I have never ridiculed the Passivhaus concept. In fact I greatly admire it, as any fair reading of this blog should make clear.

3. I've not sure where the phrase "overemphasizing efficiency" comes from. I don't think it came from me.

4. I certainly agree that Passivhaus buildings work very well indeed. That's why, after I returned from the Passive House conference in Illinois, I reported, "The Passivhaus advocates I met at the conference are responsible for some of the best new buildings in the country — buildings with extraordinarily low energy budgets."

5. I honestly don't believe that a fair reading of my reporting shows that I am engaged in "a campaign against passive houses and the folks building these." I love Passivhaus buildings and Passivhaus builders. I only raised a technical question about the cost-effectiveness of very thick sub-slab insulation.

6. As a former builder, I am well aware that some of the best building solutions come from non-scientists.

Thanks for your comments, Dr. Feist. I really do think that we are in agreement on most points. And I can assure you, I am not conducting a campaign against Passivhaus builders.

a good time betwen the years - and a successful New Year
by Wolfgang Feist

I fully agree: as long as there is a fair discussion, the scientific method will lead us to better answers at the end. That, number 1, is the most important point. It can not be emphasized strong enough, exactly in your country. It was the strength of your approach - you brought the men to the moon. And it was the lowest points in your history, every time you started to blame the messenger (science) for the message (e.g. global warming or evolution or cost of war) some did not like.

And, what I enjoy most, your point Nr. 6 - yes, this is not an academic contest. It is about homes, people and quality of life. And so I like to keep that open for carpenters, builders, ... everybody who is engaged and acts respectfully and responsibly.

You do not need to "sing the gospel" (:-). Its enough to be aware of the men and women who contributed to the development, and we both do. It was not easy all the time - we all know. But it was still successful - and might be even just in time to help us all out of the climate crises.

A lot of developments start quite expensive (remember what the first PC's had cost) and with the learning curve we succeed to make it more cost efficient. That is agreed on for almost every technical development (including PV especially). Surprisingly it was never accepted with super insulated homes. Another reason, why there were only a few ones in the 70s and even less in the 80s. But (1) without starting the business you never can get to the learning curve. And (2) super insulation was at no times that expensive most people thought it was. That in mind, it was possible to start on a small, not very expensive level (+8%) in Europe. And there was already a big step done on this learning curve (now extra investment near +5%). And now we are already at some 10% of all new buildings at least in Austria. This is not an exotic niche market!

Therefore, this development is mostly just about to get it started. If you do, you will realize all the advantages - you will never want to get back to the draughty old buildings with thermal bridges, mould problems and noisy systems and high energy bills.

And for this reason you would never regret the money for may be 1 inch "too much" of insulation - if that will allow you to really meet the standard. In Kranichstein, every Cent spent on extra insulation has already long paid back. And that was the very first building of this type in Europe (yes, it was, all earlier attempts were not really occupied but experimental boxes paid by taxpayer money - and yes, not all of them had convincing results. There were problems with too poor airtightness and with really poor ventilation systems and with all the "whiz-bang" components built-in. That is, what we fixed.).

The Gospel of Science
by Riversong

It's interesting and revealing how very defensive and disrespectful Dr. Feist can be. It's also possible that the critiques that so disturb him perhaps cut too close to the bone for his comfort.

I don't know Dr. Feist and have not engaged in an intensive study of the PassiveHaus concept, but I know enough about the PH principles and technologies to criticize it from a much broader perspective than Straube or Holladay might offer. And I do that from 30 years of experience in super-insulated home design and construction, as well as five years of teaching building science and building technology.

What Feist, Holladay and Straube all have in common is a strong faith in the scientific method (Martin also, thankfully, supports non-scientist's contributions), and that is the gospel of modern culture. Science, like all faith-based approaches to knowledge, is both dogmatic and limiting.

Building science, for instance, has mostly corroborated what carpenters already proved in the field can be accomplished by experience, intuition and commitment. And, being blind to the broader ramifications of the scientific/technological approach to life (those unintended consequences that have always followed closely behind), the logical mind concludes that taking a good thing to extremes has to create a better outcome.

Human shelter, for millions of years little more than a thin membrane offering some protection, have in the blink of an eye become isolation units that completely separate us from the natural world which birthed us, nurtures us, and sustains us - in body, mind and spirit. The only environment in which an isolation chamber is appropriate is one that is completely anathema to human life, such as outer space or the depths of the sea.

It is precisely because we have chosen to treat the natural world as the enemy of "civilized" life that we are facing the perfect storm of global crises that threaten our extinction. Alienating ourselves more completely from the embrace of nature is surely not a sane or sensible approach to living sustainably on the earth.

Much of what passes for "efficient" or "green" home-building technology is merely a deeper expression of our physical, emotional and spiritual separation from the earth. That course is surely neither sustainable nor healthy. If our homes do not reflect a visceral connection to the elemental materials and energies of nature, then they are poison to us and to earth.

Science is dogma. PassivHaus is one expression of that life-denying dogma. Dr. Feist sounds here like a religious fundamentalist whose gospel has been challenged.

Gospel of science?
by Wolfgang Feist

Robert Riversong, how do you want to decide between different opinions - we always have such types of conflict.

1. Using ideological / religious insight? (Look what the results are... these insights are so different)
2. Using old myths and convictions (I at least prefer to go to a physician then I am ill)
3. Using the authority of authorities? (Look how that went in the Italian city states)
4. Using majorities (That's a widely spread opinion - do you think, majorities can never be wrong?)
5. "let the market decide" (interesting variant, please serach for the video "Colbert Gore opponent")
6. ..... any suggestions?

I am sure that a scientific based discussion is a good basis for rational decisions; and it has proven to be a good basis for development. I agree, that it can be abused (Development of weapons, courtesy expertise, ...).

Science is not a dogma: Sceptical investigation is at the very center of science.
...and not life-denying: Nothing is more wonderful than the insights in the paths of evolution or the research on our self-awareness or the wide horizons we got from astronomy.

Look at the roots: Alexander von Humboldt, Max Born, Bertrand Russell, Erich Fromm, Albert Einstein, Karl Popper and Ernst Bloch. Yes, these are all Humanists. These persons discussed why they have chosen the (non-dogmatic) scientific approach.

Why do you think that contributions not from scientist are not welcome? What does that mean, "not a scientist"? That you do not want to be called a scientist or that you feel somehow excluded?

Welcome to GBA
by John Brooks

Dr. Feist,
I am very glad to see you comment here.
I look forward to reading your comments about low energy home construction.
Very, very few over here are making better than 50% improvements.
I think that Passivhaus is an excellent example.

Back to the Future
by John Brooks

Wolfgang,
I am one of the "Others"
I am not a Scientist ... I am an Architect.
I would like to change the subject to Light Frame Construction
Please consider my question:
http://www.greenbuildingadvisor.com/community/forum/energy-efficiency-an...

Thanks John Brooks - America goes green
by Wolfgang Feist

... I will not introduce myself too much in American business (:-). There are fortunately a lot of engaged and well educated persons in the US. You will make it - like you stated at your homepage: "While we can still build homes the 'old fashion' way, we have to ask ourselves . . . why?" Better energy efficiency will make better homes - better quality of life, and that is not an abstract issue. You will convince the world by consequently using this approach.

Useful Debate
by Pat Murphy

LIke John Brooks I apprecaite Dr. Feist involvement on this discussion.

I am not sure if all know that Marc Rosenbaum and David White wrote a well considered response to John Straube's article. It is posted on green building advisor.

http://www.greenbuildingadvisor.com/blogs/dept/green-building-blog/defen...

Martin overall has been a strong supporter of passive house. (So has Alex Wilson.) Any criticisms he makes, and some may be erroneous, is trying to advance its development in this country.

I think it is simply a very big problem. I was at the Passive House Conference earlier this year in Germany. Some translations were very good and others not so good. The materials in Germany are different. I think it is going to be a big challenge to bring this into the US in a significant way. Yet the threats of climate change tell us we need to do this quickly. This kind of dialog helps but it is very slow.

I am off to see a passive house in Portland accompanied by a builder from Yellow Springs. Tad Everhart retroffited his house here in Portland and Roy Eastman of Yellow Springs retrofitted his office building.

Apples to Oranges?
by Riversong

I agree that it's difficult, and perhaps misleading, to compare permanent envelope improvements such as slab insulation to shorter-lived mechanical enhancements such as PV. Financial return on initial investment is only one part of the equation. Financial and ecological life-cycle costs have to be factored in (as some here have proposed) - PV production and end-of-life disposal has its own enviromental costs, as does petrochemical foam insulation. And we would do well to follow Amory Lovin's dictum that the cheapest (to society and the world) megawatt is a negawatt - conservation is always to be prefered over production. But that means consuming less by our lifestyles, not using non-renewable materials to reduce the energy impact of a profligate and unsustainable lifestyle.

The whole debate over thermal losses to the ground ignores the thermal mass benefits of a warmed layer of earth surrounding our foundations and underlying our slabs. I've yet to see an analysis of the relative heat loss downward with lower insulation levels and warmer earth compared to higher insulation levels and cooler earth. This is the strategy that Passive Annual Heat Storage and Annualized Geo-Solar systems employ. In most cold climates, there is an insulating snow layer on the ground for much of the winter, and heat loss into the ground does not blow away as it does to the air or radiate to the night sky, but creates a dynamic mass benefit which further undermines the incremental benefit of additional sub-slab insulation.

Not Dogma?
by Riversong

Wolfgang,

The "alternatives" you proposed to the epistemology of the scientific enterprise are indications of the deeply dogmatic nature of what I call "scientism" - or the religion of science.

I've not only studied the history of science, but also the philosophy of science as well as other approaches to knowledge. What allowed the scientific pioneers to make great advancements in knowledge is that they were often driven by an over-arching spiritual appreciation of the mysteries of life. But, just as the followers of that great prophet and teacher we call Jesus created a corrupt and corrupting institution, those who call themselves "scientists" today tend to be true believers in the unlimited efficacy of the scientific enterprise and also highly contemptuous of other - and much older and more complete - epistemologies and cosmologies.

You say, "I am sure that a scientific based discussion is a good basis for rational decisions; and it has proven to be a good basis for development. I agree, that it can be abused…"

The first part of that statement is a solipsism: that the rational method is effective for rational decisions. But reason is only one part of intelligence, and it's been far over-rated. The latter statement – that the otherwise good method can be abused – ignores the historical fact that every scientific "advancement" has created unintended negative consequences, and much of that alleged "advancement" is more mythological than real.

You might choose to go to an allopathic physician when you're sick, but modern scientific medicine is now the leading cause of death in the US (and I'm sure elsewhere) according to the latest meta-study on the subject – most of which is unreported. The same is true of all such "progress". The "blowback" from the scientific/industrial enterprise is not accidental or incidental – it is fundamental to the very nature of the approach. And it is as unsustainable as living in isolation chambers, because it has the same effect – to isolate us from the source of life which cannot be plumbed by the rational mind.

Not dogma, ... no dagmae!
by Wolfgang Feist

Robert Riversong, we happened to live just after the time of one of the greatest injuries done on mankind: Fascism. And did not we live through times with a great amount of challenges? The cold war, ideological extremism of a lot of kind, ... What I learned from history, is, that indeed dogma were very often at the root of the big injustice which happened.

How I understand the history of science it is a history which lead to critical analysis of what we believe and like to believe. It is a history of anti-dogmatism.

I agree that were ought to be deep scepticism of what was achieved in the technological development so far. What I do not agree, is, that this lies within the fundamentals of the scientific approach. And I do not accept the identity science/industry you try to suggest.

I agree, that science needs a background of ethics. That is exactly what A. Humboldt and I. Kant realized - and what was illustrated by the history of the 20t century.

I want to send you this link to a piece of Carl Sagan: http://tinyurl.com/yel6xt3. It tells a lot of the history: The end of the library in Alexandria, the failure of ancient science to speak up against slavery...

That is, why I am still taking place in this discussion, and that is why I speak up. I love these men and women - I love their capability to grasp at least a small piece of this cosmos. I love life and I will not at all accept that science turns life-denying. And it is not - although were are not reflected inhuman acts and these have even also be done by persons who call themselves "scientists". That is, why ethics stands above science, or, better, stands above all the individual flaws each of us has.

I find this an interesting debate, almost everything coming up - I do not know whether it is useful, Pat. What is more important, is the field work going on: Each house built, each experience made (and told). And what is important is education - I really enjoy the good work done by Mike and Katrin, sharing the experience. And, Robert Riversang, that has nothing to do with "isolation chambers". Just ask the several Tenthousands of PH-users. Bring a passive house up the mountain, (hanging on a helicopter e.g) - it will take less than 4 seconds the air went out and the pressure equals that of the environment. May be that the word "airtightness" is poorly coint (:-), sorry, it was not me doing this basic research, there have been some guys from Minneapolis (I love them, too) and Arne Elmroth from Stockholm (a great building physicist). We have long been through this discussion in Europe. But I am not tired, I will explain it again, if required.

Wolfgang notes that the field
by Pat Murphy

Wolfgang notes that the field work is vital. Today I spent four hours with Tad Everhart touring his house that was retrofitted to passive house standards. Tad took PHPP training and is certified. He, Roy Eastman, and I discussed every aspect we could think of. Roy has not been certified but met Katrin some time ago and changed his building approach to go for passive house standards.

I am unsure of the history of science but know quite a bit about the builders of high performance homes. To see such examples as Tad's is exciting. His door,s windows, heat exchangers, the way he is building his window openings, jhis innovative Larson truss, and other examples are impressive. We talked a lot about how to get all the expereince communicated but came to no concrete suggestions. Roy and Tad traded information and both will do a better job on their next efforts because ot this meeting.

Dogma on Dogma
by Riversong

Feist says "the history of science it is a history which lead to critical analysis of what we believe..."

Critical analysis of all beliefs except the belief in science itself. That's the nature of a dogma: it cannot even conceive of questioning its own foundational assumptions.

The irony is that 20th century science, itself, has stumbled upon and undermined its own premises. Gödel's Incompleteness Theorem, Heisenberg's Uncertainty Principle, quantum indeterminacy, the impossibility of objective distance, super-position (Bose-Einstein Condensates), wave-particle duality, time reversal symmetry, entanglement, zero-point energy...

And yet the acolytes of science continue to think we still live in a Newtonian universe of material cause and effect. Carl Sagan is a popular apologist for the scientific endeavor, but his perception is severely limited by his belief in the veracity and efficacy of rationality. Reason is a very powerful tool, but not our only one and not the defining tool of humanity. When all you have is a hammer, as they say, everything looks like a nail.

We live at a time in which all dogma must be questioned if not challenged if we are to survive another century. The fate of the earth is at stake.

To Pat Murphy
by Martin Holladay

Pat, I appreciate your comments. And I'm glad that some people in the Passivhaus community recognize me as a friend and ally, not an anti-Passivhaus campaigner.

Not "My" Website
by John Brooks

Wolfgang,
Sorry if I confused you by welcoming you to GBA.
GBA is my favorite website ... but I am only a member.
I became aware of Passivhaus just a little over one year ago and I admit to a fanatical interest in PH.
To me the most important thing is just knowing that it is possible to achieve 90%+ improvement in enclosure design.
Passivhaus is ONE excellent example... and it is the example that opened my eyes.
Please, Please continue to post here.

stumbled upon and undermined its own premises
by Wolfgang Feist

- "The irony is that 20th century science, itself, has stumbled upon and undermined its own premises. Gödel's Incompleteness Theorem, Heisenberg's Uncertainty Principle.."
Yes, Robert Riversong, just this is what is proving the anti-dogmatic approach of science. By no way science is to be identified by pure determinism, it's not at all an irony ... these insights are beautiful hints for us to be tolerant, to keep to be open, to realise that there is more in nature than just the prejudices we have. These insights should have consequences for our culture - other than creating weapons and superfast cars. Carl Sagan says it all in that episode 13: Yes, the scientific community has to care about the society, and,

Robert, yes, I agree

has to be questioned from time to time.
Exactly because it does that, it is the best tool we have - and it is not simply a hammer, there are telescopes, too, and infrared cameras, and NMRI, and blower door test, and interferometers, and quantum circuits, ... You can not really neglect that we widened our way to perceive this world by the means of science. I agree, that we still must be decent: The thing, what we know best, is still Socrates "I know that I know nothing" - but he still knows quite a lot, and we now understand a bit better, why he was right. And our successors (so there are) will know the same about us.
But there is something less probable to give good results for our decision than questioning and reasoning: Pretending to know everything better - because of mystical insight or higher epiphany. I recommend to question such an approach.

William A. Shurcliff, the very same physicist working with highly efficient buildings later, was also one of the persons most engaged in the Pugwash movement. Is not this a shame, that there is still no entry for him in the English Wikipaedia?

@John Brooks, yes, I know that GBA is not "your" side - but I have visited yours and cited from yours (:-).

@Pat Murphy: Yes, I read the Rosenbaum/White article. Very good, a piece of real science. I admit that it is hard to answer these smart-alec allegations of Dr. Straube wihout any sarcasm. But Rosenbaum/White did, and Katrin Klingenberg did, too. I admire them all.

Still waiting for a response
by Martin Holladay

It appears that Dr. Feist has chosen not to provide a technical response to my point about the thickness of sub-slab foam. While he did e-mail me several very interesting sentences on the topic, he prefers not to make any statement publicly.

Pat Murphy noted, "Marc Rosenbaum and David White wrote a well considered response to John Straube's article." That's true, but John Straube's points were different from the points I made in the blog that Dr. Feist refers to as "disinformation," namely "Can Foam Insulation Be Too Thick?"

In addition to co-authoring a response to John Straube's article, Marc Rosenbaum also posted a response to my article on the thickness of sub-slab foam; he titled it, "Everyone is right." Interestingly, Rosenbaum didn't dispute my basic point. Rosenbaum wrote, "As to whether PV or sub-slab foam is more cost effective — there is certainly a point where load reduction should hand the baton over to renewable generation. I don't think that the costs we use for PV include depreciated output over time, maintenance (small), and replacement of failed components (like my inverter that died). Same is true for heat pumps. The cross-over point between the two needs to take this data into account. And if you think that in the future our ability to manufacture large amounts of hardware might be affected by peak energy, then all the more reason to do something once that never needs re-doing."

Rosenbaum's post appears entirely consistent with my own blog's conclusion: "PV equipment and heat-pumps have a shorter life, and require more maintenance, than sub-slab insulation. In fact, this point may be enough to convince some builders to choose 14 inches of foam over a PV array. It’s a defensible position, but it’s one that should only be made after considering the fact that the homeowners would get more bang for their buck from a PV array than from the last 10 inches of foam."

What is wrong with Dr. Feist?
by Elana

Why is Dr. Feist so defensive and angry? He has stated that Martin Holladay is spreading disinformation and has a "campaign" against passive houses, and is disrespectful with comments like "get real, guys". Martin has been respectful and kept to his perception of the facts, and has made clear repeatedly his admiration for passive houses. He has made a technical point about when sub-slab insulation may not be cost effective, and you would think he wants to reinvade Iraq (like all those other money-grubbing Americans Dr. Feist is concerned with)! I really do not understand the hysteria of the response given the technical nature of Martin's point. It is also hard to miss that for all of Dr. Feist's words and disrespectful charges, he has yet to even try to answer Martin's original point. Why would that be? Why all this talk about the nature of Science, without so much as once engaging scientifically Martin's point, which seems minor in the grand scheme of things. The passive houses Dr. Feist advocates are excellent houses, and fortunately are much less fragile than their defenders!

on PV and insulation - and whats wrong with me
by Wolfgang Feist

@Martin Holladay: There is an (I fully agree with) answer to your statement "Passive House foam is more expensive than PV" at the PHIUS blog posted by Mark Sidall. It says it all, it is public and, yes, were is not a "big gap" between your and my position on that point. I will not recommend more than 10 inches of slab insulation as the first step in a 85 kKh climate - but it might be needed, if that is the last step needed to get rid of a complicated heating/air conditioning system, which will save more money than the last inches of that insulation cost. Insulation and PV are not in a competition. We will need both. But: You'll have to do slab insulation or you will not have it later (that is at least simple to see). And you can add PV, we will do in our now 18 yr old passive house then PV is down to 25 Cent/kWh. The marginal costs of the PH-components in Europe are now within 6 to 10 Cent/kWh.

There are really elaborate answers from Katrin herself to Dr. Straube and from Rosenbaum/White. There is (almost) nothing to add - except, that I perceived it very decent, how these persons reacted. I also offered Martin to create an excerpt out of our e-mail conversation - which we both agree in - to at least have some substantial results, which may help bringing less fragile homes forward.

@ Elana I already stated: I am very much used to be beaten hard, thanks for your post. Thanks for calling the passive house concept not fragile - that is one of the advantages of these homes. That came as a surprise, in our first simulations we were not fully aware of this stability of the thermal behaviour. So, the benefits are not at all just the energy savings. That will be my last post on this side, as long as Martin does not invite me for anything else.

Mark Sidall's response
by Martin Holladay

Since Dr. Feist seems to have concluded that Mark Sidall provided a full response to my article on the cost-effectiveness of very thick foam, I went back to the post in question — http://www.passivehouse.us/bulletinBoard/viewtopic.php?f=5&t=185 — and read Sidall's response.

Here's the core of Mark Sidall's response:
"As long as the NVP [Net Present Value] for the whole building remains within acceptable cost boundaries then you have an affordable solution. .... So where does this leave EPS [expanded polystyrene]? If you made a whole house, PassivHaus or not, using EPS insulation it may turn out with a NPV that is to high — to me this just suggests that the type of insulation should be refined to address whole life costs (this may be a result of climatic considerations requiring a certain resistance, due to cost/supply issues or some other factor). Here you could optmize sub-components, such as any EPS forming a slab on grade, by improving the U-values elsewhere and/or using cheaper insulation and by reducing that of that used under the slab. To my mind this is just good value engineering practice and has nothing to do with PassivHaus."

Thank you, Mark Sidall. I think your response is entirely consistent with what I wrote. If we all believe in good value engineering practice, we will be optimizing our subcomponents — a step that may require the designer to make changes including "improving the U-values elsewhere and/or using cheaper insulation and by reducing that of that used under the slab." That's exactly what I was urging.

So Dr. Feist, considering Sidall's response — why did you consider my article to be "disinformation" and "nonsense"?

Martin is right
by John Brooks

I am ashamed to say that I jumped to the wrong conclusion.
I was part of the group that felt Martin was not being fair to Passivhaus.
I encourage others to go back and carefully read Martin's blog and comments.

Thanks, John
by Elana

It is nice to see a return to a fair reading on the part of some of the Passivhaus advocates who for some reason took Martin's points as an attack.

Happy New Year!
by Mark Siddall

First of all may I wish all a happy new year and all the best for 2010.

There has been a great deal of debate on this thread so I'm feeling very cautious about adding anything. In light of some of the discussion I would like to take the opportunity vouch for Dr Feist. Whilst we have only met face to face once it was for a full day (We traveled to London after the AECB Conference and spent the day discussing PassivHaus related issues). In my experience Dr Feist is a very open and affable person and has a great deal of respect and patience for others. (Being adversarial and disrespect does not assist persuasion but being enthusiastic, jovial and playful.) If some of the initial statements (those drawing upon stereotypes) have proven to be inflammatory then this is a great shame for I'm confident that such statements were meant playfully. That's how I read them at least - perhaps it's just a European thing ;-)

Kind regards,
Mark

Can Foam Insulation Be Too Thick?
by Mark Siddall

Martin,
If I may step into the foray for a moment. Personally, I think that what cause outrage within a proportion of the PH community was that the article effectively built a straw house just so that it can be blown down.

I appreciate that for the purposes of journalism the article had to be short - but as a consequence it failed in some peoples eyes (mine included) to present a rounded debate. Instead established a premis and then sought to demolish it. For instance the article could have hightlighted the expense of under slab foam and then simply have suggested other floor construction techniques that would prove more affordable (say a Neopor type EPS insulation - the graphite in Neopor changes the emissivity and reduces the conductivity but costs about the same, you get better thermal performance for less insulation - or a suspended floor using mineral wool TJI joists.) If you concluded that this was still to expensive you may be able to consider the PV solution, but there is another parameter to consider first.

Whilst the "PV vs. insulation" article seeks to highlight an interesting proposition it overlooks one simple fact - many PassivHaus buildings already use heat pumps for space heating and hot water. (Last I heard compact units, which incorporate heat pump technology, occupy 30% of the PassivHaus market and then there is the standard heat pump market that also supplies to the PassivHaus market.) So are did the article really compare apples with apples? It could be argued that it did not. The contention then is that the building has to be looked at as a whole rather than as a series of separate or discrete sub-systems. This brings us back to whole systems design (including value engineering). If we were to stick to sub-systems (which is a technique that I'd disagree with) I’d be interested to know which is more cost effective:

* Insulation+(Grid/Heat pump), or
* PV+(Grid/Heat pump)

I have a hunch that the insulation option will win.

Rosetta stone
by Mark Siddall

In this respect I think that one of the most powerful statements on this thread came from "Anonymous" - I think that the up-turned bowl metaphor is excellent, but I'm mindful of the fact that we all need to be looking at the same bowl !!

One thing that concerns me is that there is little attention being paid the the meta-debate. Within the current debate is that we may all be lacking a Rosetta stone. We must first recognise that we all need to use the same design datums/ assumptions (if we don't share a datum we have no common platform then we are "talking different languages"), only then once we share these values can we have truly meaningful discussion. PHPP is the ideal tool to ensure this level platform. This is incredibly important as, on the back of a great deal of detailed research and measurement, many conventional assumptions have been up turned (especially internal gains.)

Only once we agree to use the same datum can we truly determine whether we are arguing over 1 or 2 kWh/m2.yr, or 3 or 4 cents/m2.yr, which this is obviously not fruitful. Or whether we are talking about the gap between "low energy" (~60 kWh/m2.y) and PassivHaus (15 kWh/m2.yr) is sufficient to cause debate.

Please mind the gap.

Thanks for returning the discussion to technical matters
by Martin Holladay

Mark,
Happy New Year, and thanks for returning the discussion to technical matters, where it belongs.

My reaction to your points:

1. I don't think that EPS or XPS are uneconomical ways to insulate under slabs. These insulation types are economical and practical. I'm not suggesting a different insulation method; I'm just questioning the total thickness.

2. I agree that many Passivhaus buildings already use an air-source heat pump to provide space heat; in fact all of the Passivhaus buildings I saw on my tour around Urbana, Illinois in connection with the recent Passive House conference (except Katrin Klingenberg's house) used heat-pumps for space heat.

3. This fact -- that heat pumps are commonly used to heat Passivhaus buildings -- strengthens rather than weakens my basic point. (Some critics attacked me for making a foam-versus-PV cost-effectiveness comparison, saying, "You forgot to include the cost of the heat pump!") If the heat pump is already there, using PV+ heat pump to make up for the heat lost through sub-slab insulation that measures "only" 6 inches is logical.

4. Finally, your two choices don't state the situation accurately. You propose two choices:
* Insulation+(Grid/Heat pump), or
* PV+(Grid/Heat pump)

I propose instead:
* Very thick insulation + (Grid/heat pump) or
* Cost-effective (thinner) insulation + PV + (Grid/heat pump)

Keeping on the straight and narrow
by Mark Siddall

Martin
1) Thickness is irrelevant. The discussion was cost per kWh (bought or saved).
4) Okay (and remembering my fundamental disagreement with this approach). If our notional building has a heat pump in both cases then we have an even playing field (both benefit from the COP of the heat pump). Now if we run with your proposition thin ins+PV vs. thick ins then we can compare the the two energy "sources" head to head. In this I'm confident that the cost per kWh for PV will be greater than the cost per kWh saved for insulation. (Now it can be recognised that the thing that fiscally "won" - I'd suggest distorted - the argument was the heat pump.)

Cheers,
Mark

Thickness is irrelevant?
by Martin Holladay

Mark,
How can the thickness of the insulation be irrelevant?
If the first 4 inches of insulation saves x kWh, it is certain that the next 4 inches of insulation will save far fewer than x kWh.
The thicker the insulation, the fewer kWh save per inch.
Thickness is very relevant to this discussion!

Big Bad Wolf?
by Riversong

Mark Siddall wrote: "Personally, I think that what cause outrage within a proportion of the PH community was that the article effectively built a straw house just so that it can be blown down."

Now that's going to piss off a lot of straw-bale builders! Let's make this a tag team fight ;-)

Passive House Wins
by Pat Murphy

I was pleased to see the Passive House selected by Martin as one of the top ten stories of the decade.

I think the insulation vs. PV is an important discussion because it points out that there is something missing in our measures. In all this discussion no one created a simple table with BTU savings, etc. which may mean its just a piece of work that is missing or that we have a weakness in out understanding. It seems we can't talk about it in general without specifying location. For example PV costs per kwh are much higher in Seattle than Phoenix because the same panel gets less sunlight.. And insulation benefits based on thicknesses are also different in those two locations.

I wish Dr. Feist would take on this challenge and maybe add some parameters in the PHPP that would make it much easier to understand. It seems until someone works out the algorithms we will debate this without benefit.

Mark and Pat, did you read my article?
by Martin Holladay

Mark,
You write, "Now if we run with your proposition thin ins+PV vs. thick insulation then we can compare the the two energy 'sources' head to head. In this I'm confident that the cost per kWh for PV will be greater than the cost per kWh saved for insulation." But that is exactly what Dr. Straube did in the exercise I quoted in my original article! His calculations showed that the cut-off point is about R-25 — more if you are using radiant floor heat — for a house in a 7,200 heating degree day climate.

Pat,
You wrote, "I think the insulation vs. PV is an important discussion because it points out that there is something missing in our measures. In all this discussion no one created a simple table with BTU savings, etc. which may mean its just a piece of work that is missing or that we have a weakness in out understanding. It seems we can't talk about it in general without specifying location." Of course we can't talk about the optimum (most cost-effective) insulation thickness without specifying location — or at least climate. That's why Dr. Straube prefaced his remarks by saying his calculations were made for a 7,200 heating degree day climate.

Why 'thickness' is irrelevant
by Mark Siddall

Martin,
My claim that thickness is irrelevant stems from a conceptual leap I made a while back - I didn't really explain, sorry. It is the conductivity of the material that is critical. For instance, if I used a vacuum insulated panel to achieve a certain U-value, as a result of the low conductivity, it would have relatively little thickness, but potentially a poor cost per kWh saved. I know that VIPs are not the standard material of choice but it serves to make the point - it is the cost and the thermal performance (U-value) that is important not the thickness.

I don't disagree that there is a diminishing return with insulation but, as I'm sure that you are aware, it is dependent upon a range of variables including internal gains, climate, set point temperature etc. Also rather than (silly) concepts such as "payback" you have to consider lifecycle benefit (insulation keeps on giving throughout the life span of the material - the payback concept squander these additional benefits and leads to false conclusions.) Whilst this paper focuses upon retrofit all the same considerations and strategies apply http://tiny.cc/MIkm8

Mark

Full agreement!
by Martin Holladay

Mark,
We are in full agreement, it appears.

1. Yes, I agree that the R-value per inch of different types of insulation differ, and that therefore the way to measure the effectiveness of an insulation sample is by measuring the total R-value (or U-factor) of the insulation — rather than by simply announcing the sample's thickness.

2. We also both agree that thicker insulation (or increasing R-value) yields diminishing returns.

3. I also agree that determining the most cost-effective thickness of any particular type of insulation "is dependent upon a range of variables including internal gains, climate, set point temperature etc."

4. I'm also glad that Pat Murphy thinks that "the insulation vs. PV is an important discussion."

It's good to reach a point at which it's possible to announce agreement.

I read your article - but a while ago
by Mark Siddall

Hi Martin,
I've returned to the article and re-read it and I would remind you about my fundamental misgivings about this approach. I would suggest that value engineering would seek a more cost effective way to make the floor - rather than resorting PV. This was not explored - this one of my fundamental misgivings with the article. Also to my mind, with all due respect to Straube, I believe that some of his are based calculations on a number of flawed assumptions (the link in the last post can be used to begin to identify some of the flaws in the economic aspect).

I would have liked to undertake a detailed, analytical, constructive and open debate on this and I would have liked to clearly identify my disagreement with various assumptions and calculation methods. But given that there has already been a thorny debate, that has already received to much air time, and has lead to to much misunderstanding (some of which got personal - perhaps leading to entrenched views), I will not undertake this endeavor - for I do not want to cause ill will.

What can be seen it that there are some fundamental differences in approach here and the subject, the economy of energy efficiency and renewable energy technologies, is the making of a substantial dissertation (if it were to analyse in an American context/climate(s), each approach and then explain how and why the conclusions differ and determine which is the most appropriate to use.) It is obvious from the debate so far that this issue is too complex to be addressed in these posts, and I don't want to get drawn into this discussion again for fear of rekindling a more - no pun intended - heated debate.

I trust that you will respect my desire not to pursue this particular discussion any further.

Mark

Agreement
by Mark Siddall

Martin,
There are many subtle considerations that can have significant impacts. The principles are clear - it is the detail that we have both by trying, poorly (in all cases), to debate. I'm glad that we agree on the principles as highlighted in your last post. I'm sure that if we were able to meet face to face we complete arrive at total agreement. Lets put this one to bed.

Mark

Agreement by Exhaustion
by Pat Murphy

Is it worth having a conference call with a few people? This is important but hard to get via these posts. It seems an hour discussion by phone might establish the parameters and areas of agreement/disagreement that could then late be developed in a post fashion.

Its interesting to see how these things show up in the Yellow Springs Energy Task Force. It took months for us to get the concept of capacity factor.

Happy to participate in a conference call
by Martin Holladay

Pat,
I'd be happy to participate in a conference call.

Mark,
As far as I can tell you are from the U.K. Of course it's quite possible that the economics of sub-slab insulation differ in the U.K. from the U.S.

It should go without saying that it is routine for builders, engineers (and sometimes even architects) to determine the most cost-effective way to achieve building objectives. In most areas of the U.S., the most cost-effective way to build an R-40 wall is through the use of double 2x4 walls filled with blown-in cellulose or blown-in fiberglass — although regional quirks affect this conclusion.

Similarly, as far as I know, the most economical sub-slab insulation in the U.S. is XPS or EPS. That's why it is routinely used. If there is a cheaper method of sub-slab insulation, I'd be happy to learn of it — and builders would quickly adopt it.

Still, that's not the point. Regardless of the insulation material and building method you settle on, there still needs to be an upper limit when it comes to spending money on insulation. Here in the U.S., the net-zero-energy building community uses the cost of PV to determine the upper limit of insulation spending. If the incremental cost of thicker insulation costs more than PV, most builders prefer the more affordable route — especially since PV is a very expensive way to generate electricity.

In other words, if it costs more than PV, it's really really expensive.

So, that's the analytical method used for net-zero-energy housing, enshrined in BEopt sofware.

It's not the only approach. The Passivhaus approach differs. It favors very thick insulation, even insulation that costs more than PV, for two reasons: (a) PHPP software has no mechanism to throw up a red flag when the PV cost threshold is passed, and (b) there is a philosophical preference for envelope improvements over fancy technical gadgets. These decisions, as I have repeatedly written, are justifiable. All I am saying is, we need to make these decisions with our eyes open.

Conference call
by Pat Murphy

Martin, you have my e mail so please send me a time and number to call you next week to begin setting this up.

In terms of the calculations for insulation and PV, does that include the fact that the insulation may last 60 years while PV life I think is about 28 years? This should be considered in the price comparison.

[Editor's note: If your Web browser behaves like my Web browser, only 50 comments are shown on each Web page. You'll have to jump to page 2 to keep reading this thread.]