The Deans of Green

Is the U.S. ready for the passive house?

comments (12) January 8th, 2009 in Blogs

Alex Wilson, contributor

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This is one of the original passive houses at Darmstadt.

Photo: Passivhaus Institut, Germany

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A front-page article in The New York Times recently introduced the German Passivhaus concept to the American public. The article, “No Furnaces but Heat Aplenty in Passive Houses,” described the movement to build houses that keep occupants warm and safe even without heating systems. The Passivhaus movement got its start in Germany, but there are now at least 15,000 homes built to this extraordinarily tight standard throughout Europe, mostly in German-speaking and Scandinavian countries.

We’re not talking just about well-insulated houses but, in cold climates, houses with R-50 walls and R-70 ceilings, with up to a foot of foam insulation under the concrete slab, with triple-glazed windows and multiple low-e coatings, with such tight construction that mechanical ventilation is an absolute requirement.

These houses are so energy efficient that they don’t need distributed heating systems to maintain comfort, and they’re never going to drop to dangerously low temperatures if there’s no supplemental heat at all (thus, the name). The whole house can be kept at 75°F with just a few feet of electric-baseboard radiator or a tiny wall-vented gas space heater. According to the German Passivhaus standard, one of these houses can use no more than 15kwh of heat per sq. meter per year (4750 Btu per sq. ft. per year) for heating and cooling, and total energy consumption can be no more than 42kwh per sq. meter per year, including heating, cooling, water heating, and electricity. This is less than 10% of the energy use of typical American homes. The cost of building to this standard in Germany is only an additional 5% to 7%. The energy load is so low that it can be satisfied with a rooftop photovoltaic system and some solar hot-water panels to create net-zero-energy houses.

So are we ready for passive houses here? I wasn’t sure until I went to the dentist today. My dental hygienist loves to tell me about the new house that she and her husband have been building for the past couple of years. (I’m a captive audience.) They took some of my advice during the design and construction, and—despite their contractor’s protests every step of the way—built it to way-better energy standards than an average house. It’s not quite up to Passivhaus standards, but it has something like R-40 walls, good fiberglass windows, and very tight construction with a heat-recovery ventilator.

What she couldn’t wait to tell me was that in the big ice storm that hit southern Vermont a few weeks ago, when their house was without power for several days and their furnace didn’t work because it required AC power, the house never dropped below 60°F. When she was cooking (with a gas range), the temperature jumped 2°F, and when the sun came out, the temperature rose to over 70°F even with outside temperatures only in the 20s.

If they had gone just a little farther with energy features (triple-glazing with two low-e coatings, for example), I think they could have easily skipped the distributed heating system altogether. That would have approached the Passivhaus standard.

I think we’re ready for it. With concern about energy prices returning (in the past few weeks, the price of crude oil has risen 40%), with concern about the economy and whether we’ll have enough money to pay for energy, and with that ice storm reminding us how vulnerable our homes are, I’m convinced that homeowners are ready for dramatic improvements in energy performance.

posted in: Blogs, energy efficiency, architecture

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Comments (12)

prudencef writes: JerseyGal315:
You can locate Certified Passive House Consultants in your area here:
http://maps.google.com/maps/ms?client=firefox-a&hl=en&ie=UTF8&t=h&msa=0&msid=113128310491806026109.00046b9dba94c1cd8053a&ll=37.160317,-91.494141&spn=34.641159,90.527344&z=4

Prudence Ferreira
President Passive Buildings CA
www.passivehouseca.org
Posted: 11:15 pm on March 20th

JerseyGal315 writes: Email Address for JerseyGal315: jburke@langinsurancegroup.com
Posted: 3:18 pm on March 15th

JerseyGal315 writes: My husband and I are new to the passive home concept and we're hoping someone out there can guide us new-bees. (1) Can passive home design be applied to manufactured / modular home design, assuming the use of a knowledgeable architect, etc? and (2) How would we locate architects and builders in North Carolina and New Jersey who have built passive homes?
Posted: 3:14 pm on March 15th

bobmcobb writes: Hey fellow bloggers:
I work for the town of Whistler, British Columbia. We are doing a joint venture with Austrian builders to deliver a passivhaus building to our community. The building will be used by the Austrian Olympic Committee in 2010 for their Olympic hosting program and will then become a community building to support mountain bike and nordic (cross-country) skiing.
Estimates are that heating energy use will be between 14 and 16 kWh/m2/year.
The Austrian group is planning to have a conference in Whistler in late winter of 2010 to showcase their building.
Posted: 11:48 am on April 8th

Wongliozzimangopony writes: I'm with DL Design. I want to know more specifics about what I need to do during a northern California (Bay Area) remodel/addition. For example, when I asked about using cellulose insulation in 2x4 walls, with an additional layer of rigid foam over that, my Title 24 advisor said, "Great, but not necessary in your climate." I also want to use some double hung windows, but am shying away from from any sliding windows because I've been told that I just can't get a positive seal. Can my house pass a blower door test with flying colors if I use sliding windows? Can I really get my house tight enough to use a minimal heating system? (My second choice is hydronic underneath hardwood...) We need no air conditioning as it is...

Is there a functional happy medium for us Bay Area folks?
Posted: 7:28 pm on April 6th

cdnseller writes: low tech, high value?

There was an article in a national Canadian paper about a gentleman in Southern Ontario who built a standard looking house, but with:

1. south facing with more and better than usual windows
2. long overhangs to block out the higher summer sun
3. thermal sinks (concrete floors & thick internal walls) on the south side
4. He used 2x6 construction, and was methodical with the vapor barriers, then, he did an internal 2x4 framing to route the electrical/plumbing, insulated again, and vapor barrier.

he now has a comfortable house w/o a furnace, although he needed a proper ventilation system. He cited that he spent only $5,000 more - which must of factored in the savings of no furnace. I know that is subjective, but I think most homeowners looking at custom building would pay more for an energy efficient home

Posted: 8:43 am on February 10th

mddesignhomes writes: The need for passive homes has been out there for thirty years. The problem with all of our clients "rich or poor" is the up-front cost. The theory of supply and demand would eventually drive the prices down and make it more affordable, yet you need to be able to convince homeowners that passive energy would pay off in the "long" run. No matter how much we talk about it, the bottom line (money) is always an issue.

Gail Devine
mddesignhomes.com

Posted: 11:59 am on February 7th

buffer12 writes: Passive solar homes and commercial buildings have been built in good numbers, in the US, since the 1970's. There was a significant movement to apply enegry conservation and alternative energy startegies throughout the nation. Some types of passive strategies were more common in some regions while others performed better in other areas. There were a number of publications and National Passive Solar Conferences that spread the word and increased the knowlege of interested owners, developers and designers. As energy costs declined, interest by owners and developers wained. Passive solar buildings faded into the background of SUV's and McMansions. Lessons learned from over 100 projects include:
Conservation (reducing consumption) provides the best benfeit/cost ratio. Also the most sustainable solution.
Keep it simple, too much user involement makes passive active and that interest can wane. Control systems can become complex and problematic.
Look to historical construction for local area clues. For TX, shading, capturing/focusing winds and nightime mass cooling are places to start. I would provide reference sources but mine are in boxes during a construction/move. I imagine a search would offer up a rich library of references.

Posted: 1:52 am on February 6th

cougmantx writes: I am very interested in Passive Solar and PassivHaus design but find most articles relate to colder climates such as Germany and the northern part of the United States. My concern is sealing a home so tight in Texas were AC is the biggest drain on energy and more of a concern then cold could cause health problems via mold, mildew and mosture trapped with condensation. Can anyone point me in a direction whereby these issues are addressed. Thank you, warren.dennis@comcast.net
Posted: 1:31 pm on January 26th

MikeKernagis writes: Great post! Just a comment regarding Passive Houses in the US. There indeed have long been buildings employing passive solar techniques here in the US. The German Passivhaus Institut readily and rightly credits Schick, Schurcliff, Lovins, Orr, et al for the development of super-insulated buildings that passively harness the sun's energy. But, while we were enjoying low fuel prices over the past 15-20 years, the Europeans have markedly advanced the concept. Hard building science with respect to ventilation, air and moisture control, thermal bridging - along with the development of an energy modeling for very efficient buildings - have led to the development of a profound and rigorous energy STANDARD called "Passive House" (passivhaus, in German). This voluntary standard has also spawned an industry of high-performance windows and doors, super-efficient air handlers, miniaturized heating and cooling systems, thermally "broken" connections and fasteners, etc. In Europe, Passive House is a fully-realized system of building that is way beyond our fathers' passive solar house. And that system is beginning to find an audience here.

Mike Kernagis
Passive House Institute US
Posted: 10:37 am on January 16th

Beideck writes: The Passivhaus standard is a great goal. They are doing good work and deserve much credit. However, I think some of their terminology needs to be re-thought. A reader of this article is lead to believe that passive solar homes are something new and that only homes meeting their new standards is a passive (solar) home. The journalist who wrote this article is to be forgiven since the terminology used by the Passive Solar Institute is misleading. For example, the book “Homes for a Changing Climate” written by the leaders of the US division of the Passive Solar Institute claim that in 2003 “the first Passive House in North America” was built. Only a very careful and educated reader would read this and think that passive solar homes have been built in North America before very recently. In fact, passive solar homes have been around for a very long time. What they call a “passive home” is a solar passive home. However, not all solar passive homes meet their criteria to be called a “passive home.” The average person is going to be confused by this unfortunate choice of terminology and might be scared away from pursuing passive solar techniques as too new or complicated. The Passive Solar Institute should give serious thought to new terminology, at least in English speaking countries.
Posted: 9:49 am on January 13th

DLDesign writes: Not only is it time, we're overdue for low-tech, high value, cost effective solutions such as PassivHaus design. I'd like to learn more specifics about their construction details so that I could incorporate and adapt it for our local (Southern Oregon)environment. Eg: German winters are more severe and I'm sure we wouldn't need quite as much insulation.
Posted: 8:39 pm on January 12th

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