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Passivhaus Practitioners Share Their Success Stories

The Fall Symposium sponsored by Passive House New England included presentations from designers, builders, and homeowners

Posted on Nov 9 2012 by Martin Holladay

A group of about 130 designers, builders, and Passivhaus fans gathered at U Mass Boston on October 27, 2012 to attend a one-day conference organized by Passive HouseA residential building construction standard requiring very low levels of air leakage, very high levels of insulation, and windows with a very low U-factor. Developed in the early 1990s by Bo Adamson and Wolfgang Feist, the standard is now promoted by the Passivhaus Institut in Darmstadt, Germany. To meet the standard, a home must have an infiltration rate no greater than 0.60 AC/H @ 50 pascals, a maximum annual heating energy use of 15 kWh per square meter (4,755 Btu per square foot), a maximum annual cooling energy use of 15 kWh per square meter (1.39 kWh per square foot), and maximum source energy use for all purposes of 120 kWh per square meter (11.1 kWh per square foot). The standard recommends, but does not require, a maximum design heating load of 10 W per square meter and windows with a maximum U-factor of 0.14. The Passivhaus standard was developed for buildings in central and northern Europe; efforts are underway to clarify the best techniques to achieve the standard for buildings in hot climates. New England.

It's impossible for this report to be comprehensive, unfortunately, and I won't be able to do justice to all of the conference events. My report will focus on three speakers: Adam Cohen, Chris Corson, and Roger Normand. Among the presentations not reported on here:

  • A presentation by architect Jesse Thompson of Portland, who showed what specification changes would be necessary to nudge several run-of-the-mill energy-efficient projects into Passivhaus territory;
  • A presentation by Stephanie Horowitz of Zero Energy Design, who described a residential project in Brookline; and
  • A presentation by Laura Briggs that focused on the EmPowerHouse, a Solar Decathlon entry.

Adam Cohen urges clients to aim for Passivhaus

Adam Cohen is a designer at a firm called Structures Design/Build in Roanake, Virginia. In recent years, he has had a surprising degree of success convincing residential and commercial clients to build to the Passivhaus standard.

Cohen opened his presentation with some jokes about his corner of Virginia. “I work in the Bible Belt South,” said Cohen. “Right before I came up to this conference, my Obama yard signs were stolen. Someone suggested that I call this session, ‘Passivhaus in redneck country: Building for people who don’t care about the environment.’”

Cohen then shared an affectionate look back at his countercultural roots. “When I was 25, I was a hippie and an idealist,” he said. He showed us a photo of a house he built with his wife (see Image #2, below). “The house cost $3 a square foot. We lived on a commune. Back then, we were building off-grid houses. We were trying to live off the land. If we had 4 or 6 Arco solar panels, that was a screaming big PVPhotovoltaics. Generation of electricity directly from sunlight. A photovoltaic (PV) cell has no moving parts; electrons are energized by sunlight and result in current flow. system. We used gas appliances, wood appliances, gas refrigerators. We built thermosyphon solar hot water systems. We built hydraulic ram pumps out of PVC. Why did we go do all of this? Because we were poor hippies.”

Cohen has come a long way. He is now a successful designer of single-family homes and commercial buildings.

Here are more quotes from Cohen’s presentation:

On blower door testing: “We follow what I call the Duclos method of airtightness — named after Mike Duclos. First, we sheathe the entire building — right over the window and door openings, except for one door. Then we test it with a blower door, and fix any leaks we find. Then we install our windows and test again. Then we fix the window leaks. Finally, we do the mechanical rough-ins, and then test again and seal again.”

On commercial kitchens: “A commercial kitchen range hood in a Passivhaus? It can be done, but it’s not fun.”

Airtightness requires attention to details: “Liquid-applied air barriers are now standard for many commercial projects. We’re already doing a lot of this stuff, but we are doing it wrong. Why should we pay more just to do it right?”

How long is the payback period? “As soon as someone asks me about payback, I change the subject. I want to talk about return on investment.”

The advantages of design/build: “The traditional delivery system — with a separate architect, designer, owner, contractor, and subcontractors — is like an octopus with no brain. Design/build — integrated delivery — is a better system.”

Americans won’t accept hot interiors: “Europeans accept a wider indoor comfort range than Americans. But you can’t have overheating in America. We must meet the expectations of regular WalMart-going Americans — not just you and me.”

On PHPP: “There are tons of things in the PHPP that I don’t agree with. I know that a building doesn’t work with the PHPP defaults. Energy modeling is 25% science, 25% experience, 25% art, and 25% voodoo.”

Chris Corson describes two projects in Maine

Regular readers are already familiar with Chris Corson’s work. Corson first gained national attention for designing and building an affordable Passivhaus in Knox, Maine. (For more information on that project, see Striving for Passivhaus Affordability and Cold-Climate Passivhaus Construction Costs.) Corson usually specifies triple-glazed Intus windows for his projects.

At the Boston conference, Corson shared photos and construction anecdotes from the Knox Passivhaus job as well as from a deep-energy retrofit project at his own house in Belfast. (GBA published a few photos Corson's deep-energy retrofit project in an article called A Real Chainsaw Retrofit.)

Here are some quotes from Corson’s presentation:

On sub-slab insulation: “The Knox Passivhaus has R-54 sub-slab foam. Under the slab is a great place to hide insulation. It’s one aspect of a house that can’t be retrofitted.”

On space heating systems: “The house is heated with a single ductless minisplit, a Mitsubishi MUZ-FE12NA [outdoor unit] and a MSZ-FE12NA [indoor unit].”

On airtightness: “We blower-door tested the house 7 or 8 times. It ended up at 0.284 ach50.”

On the deep-energy retrofit project at his own house: “Before the retrofit, the house burned 1,100 or 1,200 gallons of oil per year for space heat and domestic hot water. We did a chainsaw retrofit, the method developed by Harold Orr and Rob Dumont. We cut the eaves off the house. We took a straight-up PERSIST approach, and wrapped the entire house with Ice & Water Shield. It was expensive. Then we installed 5.5 inches of polyisoPolyisocyanurate foam is usually sold with aluminum foil facings. With an R-value of 6 to 6.5 per inch, it is the best insulator and most expensive of the three types of rigid foam. Foil-faced polyisocyanurate is almost impermeable to water vapor; a 1-in.-thick foil-faced board has a permeance of 0.05 perm. While polyisocyanurate was formerly manufactured using HCFCs as blowing agents, U.S. manufacturers have now switched to pentane. Pentane does not damage the earth’s ozone layer, although it may contribute to smog. to wrap the house. We bought the used polyiso from Insulation Depot. We used a lot of 8-inch Timberlock screws — 4,000 or 5,000 Timberlocks.”

On Lunos fans: “We installed eight Lunos ventilation fans — four pairs of fans. It’s a really cool device. It has a ceramic core for heat recovery. The fans cost $1,200 a pair, and they are quiet. We’ve lived in the house for nine months. The air quality is definitely better. The fans are performing better than expected.” (For more information on the Lunos ventilation fan, see European Products for Building Tight Homes.)

On fiberboard sheathingMaterial, usually plywood or oriented strand board (OSB), but sometimes wooden boards, installed on the exterior of wall studs, rafters, or roof trusses; siding or roofing installed on the sheathing—sometimes over strapping to create a rainscreen. : “On some projects we’ve used high-perm fiberboard for exterior sheathing. It’s made in Canada, and it’s expensive. It worked; it did its job. But it’s difficult to work with. It’s hard to install. It’s dirty. It smells like asphalt. When we started installing the cellulose insulationThermal insulation made from recycled newspaper or other wastepaper; often treated with borates for fire and insect protection., it really bellied out. Fortunately we caught the bellying before it became a big problem. We finished the job by watching it closely and babysitting the insulation contractor.”

On the new European membranes: “We’ve done homes without exterior sheathing using an exterior membrane system called Solitex Mento Plus. This stuff is waterproof and UV-resistant. It’s simple and fast to install, and clean to work with. It does require a considerable amount of strapping. You need battens and counter-battens to keep it from bowing out. Even with all those battens, there still is some bowing. We have also used membranes on a roof. We installed Solitex Mento 1000 as a sarking membrane over the roof trusses. It’s waterproof. Again, there is no exterior sheathing — just standing-seam metal roofing over the purlins. We did install OSB under the roof trusses as an air barrier, however.”

Roger Normand talks about his Passivhaus project in Maine

Roger Normand (like Chris Corson) is well known to regular GBA visitors. Roger and his wife Lynn are building a new custom home in Saco, Maine, and they are aiming to meet the Passivhaus standard. For the past several months, GBA has been publishing Roger’s blogs about his new home, which is still under construction.

Guided by architect Chris Briley and energy consultant Marc Rosenbaum, the Normands have been discovering the joys and complications inherent in most Passivhaus projects. Roger's blogs describe the downs as well as the ups of building a new custom home.

At the October 27 conference in Boston, Roger Normand and Chris Briley took turns presenting information on the Normands' new home. I've excerpted a few quotes from Roger Normand's presentation below.

On fossil fuel: “I worked for the Department of Defense. Our energy policy is based on using the military to protect our energy supplies.”

On the Passivhaus standard: “I read a lot of things about designing high-performance homes. I stumbled onto LEEDLeadership in Energy and Environmental Design. LEED for Homes is the residential green building program from the United States Green Building Council (USGBC). While this program is primarily designed for and applicable to new home projects, major gut rehabs can qualify. , and then I stumbled onto Passivhaus. I liked the intellectual rigor of the standard. I liked the fact that it was a performance metric. But I’ve discovered that we must pay a huge premium for high-performance windows and high-performance ventilation equipment. And you can’t count the output of your PV system toward meeting your Passivhaus goal, which doesn’t make sense to us.”

On appraisals: “If you’re building a house, you have to go to the bank. The bank wants an appraisal. We’ve learned that it ain’t easy. We’ve contacted three appraisers. They all professed to have green credentials. The first appraiser gave a value of zero for the energy efficiency features of our home. I went ballistic. Fortunately, the bank agreed with me. Finally, a different appraiser gave us credit based on the value of being net-zero for seven years. Why seven years? Well, that’s how long Americans usually stay in a house before they move. This is really a ‘no tickee, no laundry’ situation. People can’t afford energy features because the appraiser won’t put any value on it.” (For further discussion of this topic, see Roger Normand's latest blog, Seeing Red on a Green Property Appraisal.)

On specifying windows: “Picking windows is not easy. We are stuck with going with European windows. We started with Pella windows, but their performance was not even close to what we needed. Picking windows is not intuitively obvious.”

On the bottom line: “It ain’t cheap going green. We’re going to end up at about $220 per square foot.”

A panel discussion featuring three old hippies

The last event of the day was a panel discussion moderated by Jesse Thompson, who introduced the featured speakers — Adam Cohen, Marc Rosenbaum, and me — as “three old hippies.”

Since I was sitting at a table in front of the crowd, I was unable to take notes, so I can't report on what was said. Fortunately, there is a video of the panel discussion. Here is the first segment of the video:

Below are links to Part 2 and Part 3 of the panel discussion:

Martin Holladay’s previous blog: “Fans in the Attic: Do They Help or Do They Hurt?”

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Image Credits:

  1. Image #1, #4 and #8: Martin Holladay
  2. Image #2 and #3: Adam Cohen
  3. Image #5, #6, and #7: Chris Corson
  4. Image #9: Roger Normand

Nov 9, 2012 9:39 AM ET

Although there were many
by christian corson

Although there were many extremely valuable notions that I took away from the symposium. There are a couple of 'terms' that I will adopt and incorporate into my vernacular. I would like to especially thank Adam Cohen and Jesse Thompson for both of them respectively.
The 'terms' are.....................

"Meat Sweater" ~ Adam Cohen
"Apocalyptophilia" ~ Jesse Thompson

Thanks Guys!

Nov 9, 2012 9:55 AM ET

by Jason Miller

I'd love to hear some tips on getting appraisers to consider energy savings. I had no success with my PH renovation project here in Kansas. In his opinion, if it doesn't exist in three neighborhood houses (for comparison), it doesn't contribute to his appraisal. What a pain.

Our local credit union was very flexible otherwise, and I'd like to try approaching them directly with some of the energy efficiency details.

Nov 9, 2012 10:05 AM ET

Protecting ourselves from apocalyptophilia
by Martin Holladay

It's true that the peak-oil crowd is tinged with apocalyptophilia, and it's useful to be aware that there is a human tendency to be excited by (and attracted to) the coming apocalypse -- the one that is always predicted but never quite arrives.

However, for the time being, the word "apocalyptophilia" is mostly used by climate-change deniers to ridicule those who believe that climate change is anthropogenic. (See, for example, this blog.) For that reason, the word has limited utility at the present time, in my opinion.

Nov 9, 2012 10:11 AM ET

Response to Jason Miller
by Martin Holladay

Stay tuned for more articles from GBA on the topic of green appraisals. Next week, we plan to begin publishing a three-part series of articles by Roger Normand on the topic.

In the meantime, check out these articles on our website:

Green Building Appraisal and Financing Issues

Green Home Appraisal Woes

A Step Toward Fairer Green Home Valuations

When Green Poses an Appraisal Problem

Q&A: Bad Appraisal on a New Green Home

Q&A: Refinance and Appraisal of Net-Zero Home

Nov 9, 2012 12:22 PM ET

"Apocalyptophilia" and shades of grey...
by Lucas Durand - 7A

I've never liked this term...
Partly because of the reason that Martin mentioned.
And partly because it implies a sort of binary vision of the future (ie: everything's going to be just rosy! or we're doomed!) - when in fact, there are many shades in between.

Besides, one person's apocalypse is just another day in some other person's "hard knock life" - remember all those bankers throwing themselves out of windows during the great depression?

Nov 9, 2012 3:41 PM ET

I especially enjoyed Adam Cohen's comments
by Lucy Foxworth

As a way of illustrating the importance of surface to volume ratio and its relationship to insulation, Adam Cohen declared that he was a perfect "Passive House". Chris Corson cannot use that analogy, his volume is too low.

Great conference, funny, educational, interesting, and inspiring. And it was nice to meet some of you guys.

Nov 9, 2012 9:46 PM ET

Edited Nov 9, 2012 10:01 PM ET.

No laughing!
by christian corson


Thanks for the etymology lesson! I some how, in the cobwebs of my middle aged mind remember reading that blog somewhere. As far as usefulness of the term goes, cu m se cum sa. I just think it is funny. Thats all , just plain funny. I grew up in a household where we were taught to prepare for the end. Apocalyptophilia hits the nail on the head. Its fascinates me, our humanistic addiction to impending doom. Its a by-product of mortality. Death and taxes.
Irregardless, anthropogenic climate change exists. And even if it isnt man exacerbated (which it clearly is) its still a problem.

Lucy- Too funny. I might be Low volume but I have decent S to V ratio. Small footprint but tall with no extraneous bump outs ...........I'm working on my meat sweater, however . Insulation to come.

I look forward to reading some more about appraisals. That is a problem. Its ironic really because the problem is typically that there are no comps. People that build, retro, or live in, good high performance homes love them and typically stay for a long time, like forever ; if you sink 60 grand into a home you still have a death pledge on. If you build a new Passive House, its warm and comfortable, has very low cost of ownership and is ideally healthy to live in............. why move?............
There are currently 46 certified or pre certified PH projects that have gone through PHIUS and a handful of others certified through PHI.......there are since 2006............ ZERO sales that I know of including the PH's that have been built on spec.

Nov 10, 2012 10:41 AM ET

Roger Normand and Edgewater Haus
by Phil Lawson

I am interested in the $220/ sq ft cost for Edgewater Haus: what was included in that estimate? ie is that comprehensive costs including architect, consultant, site work... or cost of the building itself? Thanks!

Nov 10, 2012 11:47 AM ET

wrong lessons from surface:volume
by Skip Harris

I'm troubled. A compact design is most efficient and I am all for it, but PH pushes us toward more square feet as well. Saying that Cohen is a perfect PH because he has a smaller surface/volume ratio ignores the fact that a house/body with less surplus volume would
1) still have all the functionality of the larger unit (or better)
2) have a smaller surface (even though the ratio is worse)
3) use less over-all energy.
4) require fewer natural and financial resources to create and maintain

A rating system that grades a house on functionality would be better, but darned if I can figure out how to do it. Does one look only at energy use per rated occupancy and end up with windowless styrofoam cubicles with fold-down beds? Does one decree certain minimum floor spaces for a mandated list of uses?

Nov 10, 2012 2:44 PM ET

Adding a finished nice custom
by aj builder, Upstate NY Zone 6a

Adding a finished nice custom non-PH home complete with septic, well, landscaped, driveway, walks, home to raw treed land here, is much more than $220/sqft.

I find often that many many costs are not fully accounted for when discussing home costs.

Nov 11, 2012 5:54 AM ET

Response to Dustin Harris
by Martin Holladay

Needless to say, Adam Cohen's joke about his shape was just that -- a joke. It was not an indication that he promotes larger houses that are a little plump in the middle.

However, you make a good point. A small house with a bad surface-to-volume ratio may well use less energy than a big Passivhaus with a good surface-to-volume ratio.

Nov 11, 2012 1:55 PM ET

Edited Nov 11, 2012 2:01 PM ET.

Martin: thanks, but...
by Skip Harris

I find "bad surface-to-volume ratio" far too easy to misinterpret as a "poorly-designed non-minimized surface-to-volume ratio". I think you meant "The best small house will always have a worse surface-to-volume ratio than the best big PH, but may well use less energy".

Please forgive my obsession with minutia. I love to play with the inherent ambiguities in words, but they are often frustrating when trying to clearly communicate.

Nov 11, 2012 2:52 PM ET

my guess
by John Brooks

Martin probably meant to say Exactly what he did say.

Nov 11, 2012 4:47 PM ET

I think we're losing sight of the real issue here....
by Dan Kolbert

How long does it take Adam every morning to get his 'stache looking so cool?

Nov 11, 2012 11:36 PM ET

Response to Phil on $220/SF
by Roger Normand

Phil, that was a budgeted cost, which excluded architect, consultant, certification, land acquisition driveway finish, landscaping. It did include allowances for many items such as stone, electrical, appliances, kitchen. Tempering the cost is that we desired more architectural interest than the typical PH we've seen. We've already had a number of cost increases, and the meter is still running. So we'll see what will be our final SF cost.

Nov 12, 2012 9:24 AM ET

Response to Dustin Harris
by Martin Holladay

You're right -- "non-minimized" is much easier to understand than "bad." I guess I wasn't thinking clearly.

Nov 13, 2012 12:32 PM ET

small house penalty
by Robert Swinburne

It is simply easier to reach Passive house energy level on a per square foot measure - economies of scale. Less energy use is always better, however, so small house design is preferable. Passive house standards are from Europe where most people don't live in single family houses. So perhaps that is more the underlying problem. They weren't really thinking about single family homes when developing the standards.

Nov 13, 2012 12:44 PM ET

Response to Robert Swinburne
by Martin Holladay

Thanks for you comments. For more discussion of the Passivhaus standard's small house penalty, see:

Are Passivhaus Requirements Logical or Arbitrary?

A Passivhaus Rebuttal: In Defense of the Standard

Nov 14, 2012 10:15 AM ET

Appraisals of Passive Houses
by Chris West

Hi Jason. We have had similar issues in Vermont. The good news is that the National Appraisers Institute will be implementing energy based appraiser education by 2015 for new appraisers and continuing education for existing appraisers. The bad news is that it is still 2 years away.

In Vermont we also have problems with the definition of 'standard heating plant'. I have clients that got hit with a 1% increase on their mortgage rate due to the fact they wanted to heat their Passive House with a mini-split.

All issues we hope to see changing over the next few years.

I agree that going to a local credit union that doesn't sell their mortgages but holds them in house is a great option. We are working in Vt with a credit union who is interested in supporting high efficiency buildings through offering mortgages where traditional banks balk.

Good luck with your project and appraisals in Kansas!

Nov 14, 2012 5:55 PM ET

Dreaming of the Apocalypse
by Jesse Thompson

Chris & Martin,

I won't presume to have invented the term Apocalyptophilia, but I didn't first hear it from Climate Change deniers. I got it from Alex Steffen of Worldchanging fame.

Here is his great essay on the subject called "Night, Hoover Dam":

"I could do it. It'd be a world for the strong then, for the unhesitating, and that was a sweet strong dram. And before I knew it, I was off on the whole Apocalypse trip: I'd pull together some hardass guys and butch women; we'd grab some remote parcel, and cut the roads nearby with explosives and blocked culverts; I'd learn hunting, and triage medicine, the hotwiring of cars and solar panels; we'd have caches, night vision goggles, camouflage outfits, and mark out fields of fire, strongpoints and perimeters; there'd be a rusty windmill and row after row of canned food on the shelves in our bunker -- it'd be like the Whole Earth Catalog, circa 1974, run backwards through a filter of the Anarchist Cookbook and 2600. It'd be fun, good clean rough living. In time, we'd move back into the cities and hunt deer on the abandoned overpasses, like Chuck Pahalniuk's Space Monkeys. We'd do fine. I knew it."

"But real apocalypses are sordid, banal, insane. If things do come unraveled, they present not a golden opportunity for lone wolves and well-armed geeks, but a reality of babies with diarrhea, of bugs and weird weather and dust everywhere, of never enough to eat, of famine and starving, hollow-eyed people, of drunken soldiers full of boredom and self-hate, of random murder and rape and wars which accomplish nothing, of many fine things lost for no reason and nothing of any value gained. And survivalists, if they actually manage to avoid becoming the prey of larger groups, sitting bitter and cold and hungry and paranoid, watching their supplies run low and wishing they had a clean bed and some friends. Of all the lies we tell ourselves, this is the biggest: that there is any world worth living in that involves the breakdown of society."

Nov 15, 2012 6:30 AM ET

Reponse to Jesse Thompson
by Martin Holladay

Thanks for sharing excerpts from Alex Steffen's essay. Good stuff.

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