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More Passivhaus Site Visits in Washington State

Part Two of Martin’s report on his visit to construction sites and a Passivhaus conference in the Pacific Northwest

Posted on Apr 15 2011 by Martin Holladay

This blog, a report on my three-day visit to Passivhaus construction sites and the 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. Northwest conference in Washington state, picks up where last week’s blog left off.

After leaving the North residence job site, we drove to the Freas house, another construction site in Olympia. The steep site has a dramatic view of Budd Inlet, an arm of Puget Sound, to the west. (Author's postscript: On August 15, 2013, the New York Times published an article on the Freas house: "The Passive House: Sealed for Freshness.")

A modern house with a great view

A design/build company from Olympia, The Artisans Group, is building a single-family Passivhaus on the site. Designed by architect Tessa Smith, the house conforms to a severely modern aesthetic: it’s a flat-roofed rectangle.

Smith is proud to report that (with the possible exception of some gaskets here and there) it’s a no-foam house. The floors, walls, and ceiling are all insulated with blown-in fiberglass. After their insulation contractor had trouble achieving required densities while insulating sheathed walls at the North residence, Smith resolved to change their approach. “We’re not blowing any cavities blind anymore,” she said. “We’re blowing through netting.”

Here’s a summary of the Freas house specs:

  • Area: 1,350 s.f. (“treated floor area” = 1,137 s.f.)
  • Foundation: unconditioned uninsulated crawl space
  • Wall framing: Double 2x4 walls
  • Air barrierBuilding assembly components that work as a system to restrict air flow through the building envelope. Air barriers may or may not act as a vapor barrier. The air barrier can be on the exterior, the interior of the assembly, or both.: OSB with taped seams on interior side of insulation
  • Wall 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. : Vapor-permeable fiberboard
  • Floor insulation: 24 in. blown-in fiberglass (R-91)
  • Wall insulation: 14. in. blown-in fiberglass (R-55)
  • Ceiling insulation: 24 in. blown-in fiberglass (R-91)
  • Windows: Triple-glazed Pazen EnerSign; SHGCSolar heat gain coefficient. The fraction of solar gain admitted through a window, expressed as a number between 0 and 1. = 0.54 (glazingWhen referring to windows or doors, the transparent or translucent layer that transmits light. High-performance glazing may include multiple layers of glass or plastic, low-e coatings, and low-conductivity gas fill. only)
  • Mechanical ventilation: Zehnder HRV(HRV). Balanced ventilation system in which most of the heat from outgoing exhaust air is transferred to incoming fresh air via an air-to-air heat exchanger; a similar device, an energy-recovery ventilator, also transfers water vapor. HRVs recover 50% to 80% of the heat in exhausted air. In hot climates, the function is reversed so that the cooler inside air reduces the temperature of the incoming hot air.
  • Domestic hot water: Gas-fired Navien instantaneous heater
  • Design heat load: 7,000 BTUBritish thermal unit, the amount of heat required to raise one pound of water (about a pint) one degree Fahrenheit in temperature—about the heat content of one wooden kitchen match. One Btu is equivalent to 0.293 watt-hours or 1,055 joules. /H
  • Space heat: hydronic radiator circulating water from domestic water heater
  • Air leakage rate: 0.49 ach50

To learn more about this house and the other sites mentioned in this blog, be sure to click on the photos and read the captions.

Recycling an unwanted nuclear power plant

In the late 1970s, the state of Washington embarked on an ambitious and financially disastrous plan to build a string of nuclear power plants, in spite of the fact that the region is blessed with abundant and cheap hydropower. The agency in charge of building the plants, the Washington Public Power Supply System, had an unfortunate acronym: WPPSS. Almost immediately, the acronym began being pronounced “Whoops.”

Whoops indeed. A variety of factors — huge cost overruns, the Three Mile Island disaster of 1979, and mounting opposition from antinuclear activists — finally led to the abandonment of the ill-fated WPPSS project. As the financial house of cards underpinning the project began collapsing, WPPSS defaulted on $2.25 billion of municipal bonds — the largest municipal bond default in U.S. history.

Construction at one of the WPPSS reactors, the Satsop Nuclear Power Plant in Satsop, Wash., began in 1977. When construction was finally halted in 1983, the plant was 80% complete. Hundreds of millions of dollars were wasted on the facility, which never went on line.

In 1995, someone decided that the unused buildings — many of which have 5-foot-thick walls made of reinforced concrete — should be put to use. Now known as the Satsop Business Park, the facility rents space to start-up businesses.

Workers from The Artisans Group are now building double-stud Passivhaus walls in the one of the Satsop reactor buildings. (There are several advantages to building wall panels indoors, including the avoidance of rain — a common occurrence in the Pacific Northwest.) Since the reactor was never started up, there are (fortunately) no radiation worries at the plant. Considering the recent news from the Fukushima Daiichi plant in Japan, the Satsop tale reads like a swords-into-plowshares fable.

The Passive House Northwest conference

About 200 people gathered on March 18, 2011 for the Passive House Northwest conference on the campus of Evergreen State College in Olympia. Several manufacturers and distributors were marketing their wares at the small trade show, including Albert Rooks of Small Planet Workshop. Rooks was displaying a variety of Siga air-barrier tapes from Switzerland and samples of Agepan fiberboard sheathing from Germany. (Agepan sheathing is thicker and stiffer than the fiberboard sheathing usually sold in the U.S.)

After I delivered the conference’s keynote address — my topic was “Passivhaus Requirements: Logical or Arbitrary?” — we were treated to a full day of presentations by top-notch energy experts, designers, and builders.

Here are some notable quotes from some of the presenters at the conference:

  • Michael Aoki-Kramer, RDH Building Sciences: “It costs 3 to 15 times more to fix it later than to do it right the first time.”
  • Dylan Lamar, Green Hammer: “PHPP is accurate only for a superinsulated airtight building.”
  • Jan Fillinger, EcoBuilding Collaborative of Oregon: “It took us a month to do the PHPP data entry and meet the standard. At first, we didn’t understand the importance of a low surface-to-volume ratio.”
  • Tessa Smith, The Artisans Group: “We joke that PHPP is so German and insane, but it is the world’s best energy model.”

My favorite event at the conference was the “Point Sixpack” awards: the annual presentation of a sixpack of beer to each builder who has achieved blower-door results of 0.6 ach50 or better. This year’s recipients included Alex Boetzel of Green Hammer in Portland; Ted Ethan and Mitzi Kugler of West Linn, Oregon; Joe Giampietro, architect of the Mini-B; Dan Whitmore of Black Bird Construction in Seattle; Jan Fillinger (Studio-E Architecture) and Win Swafford (EcoBuilding Collaborative) of Oregon; Glenn Haupt of Bend, Oregon; Milos Jovanovic of Root Design Build in Portland; and Tessa Smith and Randy Foster of The Artisans Group.

Hearty congratulations to all of the Point Sixpack recipients!

Summing up

The builders and architects I met in Washington state are smart, energy-savvy, and eager to build superinsulated houses. Their regional organization, Passive House Northwest, is unique: no other regional Passivhaus group is as well organized and well funded, and no comparable regional Passivhaus conferences exist in other areas of the country. Their group can serve as a model for other builders and designers interested in superinsulation.

More important, everyone I met was friendly and had a sense of humor, and the locally brewed beer I sampled was hoppy and refreshing — all in all, an excellent visit.

Last week’s blog: “Visiting Passivhaus Job Sites in Washington State.”

Tags: , , ,

Image Credits:

  1. Martin Holladay

Apr 15, 2011 9:22 AM ET

Edited Apr 15, 2011 2:24 PM ET.

A positive result reached: Local beer tests well!
by albert rooks


I'm glad the beer went down easily. As I recall, that was one of the initial goals of the visit: "Sample some finely crafted beers from the Pacific Northwest". And... Since you're here... we might as well see some super insulated construction!

I'm happy to be reminded that there is a point to making all these good buildings: Healthy places to meet, talk and enjoy the creature comforts of life.

All the best from Passive House Northwest.
Albert Rooks, Secretary

Apr 15, 2011 12:53 PM ET

Joists in Picture
by Andrew Quinter

It appears that one of the joists in the picture was cut in half for the 3" ducts. I hope the sheathing is not supporting a floor.

Apr 15, 2011 12:57 PM ET

Response to Andrew Quniter
by Martin Holladay

The answer to your question can be found in the caption to Image 3. The 2x6s are not structural. Here's what the caption says:
"Here's a great idea: installing a layer of 'false ceiling framing' to accommodate wiring and ductwork. At the Freas house, the builders installed a layer of OSB on the underside of the open-web ceiling trusses to establish an air barrier at the ceiling. The OSB seams were carefully sealed with Siga tape from Switzerland. Then a suspended ceiling was installed — 2x6 framing hanging on small Simpson clips — so that electricians and HVAC contractors don't disturb the air barrier."

Apr 15, 2011 5:21 PM ET

Oy, those R-90 envelope
by mike eliason

Oy, those R-90 envelope assemblies are killer.

Good to see more panelization here in the Northwest. It’s pretty much standard practice in the EU now, and with the increased utilization of gaskets hopefully something we’ll see more of.

Milos Jovanovic is with Root Design Build.

Any ideas as to how long til Agepan (or cross laminated timber) are manufactured here, and not just imported?

Apr 15, 2011 5:34 PM ET

Response to Mike Eliason
by Martin Holladay

In Seattle and Olympia, is "killer" good or is "killer" bad?

Thanks for providing the name of Milos's firm.

Concerning your question, "How long til Agepan (or cross laminated timber) are manufactured here?", I imagine that a production facility would want to see a potential market of more than 2 or 3 dozen Passivhaus buildings a year.

Apr 15, 2011 5:41 PM ET

in this instance, killer =
by mike eliason

in this instance, killer = bad. even with the lack of solar gain mentioned in conference, that seems really high for our mild climate. i'm guessing partially due to low SHGC of the pazen (i consider 52% too low, especially for our region)

yes, i would imagine more than 20 or 30 PH projects a year - but it has useful applications in non-PH buildings as well.

Apr 15, 2011 11:32 PM ET

CLT plant is developing in Montana
by albert rooks

Martin and Mike,

Montana Sustainable:, has been developing the US's first Cross Laminated Timber plant in Whitefish Montana. The development has been going on for a while and they have been partnering with some very solid German and Austrian companies.

The exciting news is that they have finalized North America's first commercial CLT project. I spoke to Pat Clark last week and the final numbers were due today. It will be a very interesting project. The CLT Panels will be built in Austria by the partner, containerized, and erected by crane in Whitefish this summer. The project is a very nice multistory on an infill lot.

CLT construction means that, the panels are all set in place by crane in a few days. The air sealing is done on the panels when the entire building is up, and then the exterior is wrapped with continuous insulation. For this building, they've chosen to tape for airsealing, and then wrap with Roxul. It appears to me to be an excellent diffusion open wall. There is not a layer that will not pass some amount of water vapor, so it should live a long and healthy life (in 100's of years?) if reasonably maintained.

If it's interesting to anyone, I wrote a blog entry of a CLT building under construction that I walked. It's in 3 parts at: I apologize in advance, the pictures load very slowly due to file size. The bio mass plant in the basement was exceptionally impressive.

The opportunities for CLT's in the US are good. As engineering improves, these structures can grow to significant multistory structures like you can see in the blog entry. They essentially compete with concrete and steel.

I attend Sunday Mass regularly at "The Church of the Sacred Wood Fibre"... Meaning: I like wood. Anytime I see wood effectively competing with concrete in any structure, I think it's a very positive development.

Apr 16, 2011 10:20 AM ET

Edited Apr 16, 2011 10:22 AM ET.

by j chesnut

Dylan Lamar, Green Hammer: “PHPP is accurate only for a superinsulated airtight building.”

I've wondered about this. Did Dylan determine this by experience or is this an official disclaimer from PHI?
It would be interesting to understand why this is the case if it is in fact true. Other than the 'ventilation' worksheet doesn't the PHPP provide a thorough static model of the heat loss/ gains physics that happen for any structure?

I suspect when uncontrolled air exfiltration becomes high enough some of the mathematical assumptions must change. As I have attempted to model my own home in PHPP (ACH50 3.5, no mechanical ventilation and without a well defined thermal envelope) I get annual heat energy consumption in the PHPP significantly greater than my actual usage. (Though the model may need another round of checking the accuracy of the inputs.)

Apr 16, 2011 11:57 AM ET

Agepan information
by James Morgan

Albert, can you give us an R-value for the Agepan, and confirm that it's fully structural for wind bracing? Hoping to see some alternatives for petrochemical SIS coming along, even if it'll take a while to become generally available.

Apr 16, 2011 12:43 PM ET

Passivhaus, but Green?
by Matthew Amann

GAS!?! fired water heater instead of Solar hot water? Oy, Still don't totally understand the fiberglass preference....

Apr 16, 2011 4:00 PM ET

by mike eliason

I met the smartwood guys at the pdx phnw conference. The thought of importing CLT seems to erase the merits of using it. Looking forward to the things going on in BC despite weyerhausers disinterest in it. Do you have embodied energy for agepan? TU Muenchen has a report that shows holzfaser graue energie (embodied energy) at about the same as eps low density. Is the manufacturing process that intense?

Apr 16, 2011 7:24 PM ET

j chesnut
by Doug McEvers

You could be dealing with the shadow concept "infiltration heat recovery".

Apr 17, 2011 11:45 AM ET

Edited Apr 17, 2011 11:50 AM ET.

Agepan values
by albert rooks


The Agepan THD 230 is R-2.84/inch. The 60mm (2-3/8") thick boards that I'm going to work with = R6.81 at 60mm. They will not carry the shear loads. We are going to start with these for diffusion open wall assemblies that already have a layer of OSB or Plywood that will pick up shear.

I see two initial simple assemblies:

1: Double stud/larsen truss with OSB/Ply interior and Agepan exterior. The function of the Agepan will be the exterior skin: Hold the dense pack cellulose in without deforming while adding to the overall R value of the wall. The Assembly is diffusion open from the OSB out with the final layer of Agepan at 18 perms.

2: I'm curious how it will fit on our Energy Star (or other homes): The large home penalty is to wrap an R5 exterior layer around the house. The "go to" product is of course foam. I'd like to see a house or two done with this material. I think (read: hope) that we find unexpected advantages along the way other than the obvious: that it's a wood product & that it's vapor permeable. It holds fasteners, but we still have to learn what kind and how well. It cuts easily and has no vocs or harmful off gassing. No more pink jobsites? You never really know what you'll find until you get into it.

Since the material is woodfirbre & wax... all bound together by PU... 60mm thick and on a tongue a groove board, house wraps are redundant as the material is "rain shedding" (they say). Exterior seems can be taped with the right tape: Siga Wigluv + Dockskin primer, and then a ventilated rain screen is added.

If some of the insulation applications of foam can be picked up by wood products, then I'm in. Obviously we all see a significant increase in insulation values for all basic assemblies coming down the road. My concern is that as an industry, if we begin to wrap or spray everything with foam, then my goodness... That's going to be a lot of foam.

Here in Olympia Wa, we have a healthy and growing deconstruction and building material recycling opportunity with the local Habitat for Humanity Re-Store. The framing material is already hard to deal with. Once the standard practice for cavity insulation and air sealing is a spray foam, I think it's safe to say that that material is now consigned to a single use lifespan. Once the lifespan is done, then into the landfill its goes... Foam and all.

The point of developing this kind of material in the US is looking at the whole product life cycle: Raw material collection & production, product installation, and then finally a recycling or composting option at the end of the life cycle. If other cultures have developed good insulation boards from woodfibre, then we can do it here in the US and Canada also.

I'll be visiting the Agepan factory in Germany, as well as building sites in late May. If you want to stay up with what I learn, feel free to RSS the "Architectural Travel Blog", or perhaps better, subscribe to the "Newsletter" at

Apr 17, 2011 12:12 PM ET

EE And Import
by albert rooks


Yes... Certainly importing the CLT's erases the expected benefits. But... You have to start somewhere. There are investors, but both the theory and market must be proven before one can invest in the production plant.

To set up a CLT plant is no small thing. The two large functions are: 1, Laminating the panels with a very large press. (=$$). 2, cutting the panels.(=$$$) To make a wood CLT plant really competitive the machining is done by a large CNC (Hundegger or others). The idea is that once a panel is in the machining bay, the CNC cutting center is feed cutting instruction from the CLT Plants computer system. These cutting plans were developed as the project was modeled.

We do the same thing in the cabinet industry regularly. There are any number of CNC routers in shops that will take a 4x8 sheet of material and machine it into final parts in minutes. A CLT Plant "cutting bay" is the same thing... with much larger panels.

Due to the equipment costs, you have to walk a while before you run.

ME: "Do you have embodied energy for agepan? TU Muenchen has a report that shows holzfaser graue energie (embodied energy) at about the same as eps low density. Is the manufacturing process that intense?"

I have to say that that comes as a surprise to me. Sadly all I can say at this point is : "dunno". I don't have any EE experience yet, so I don't know how to make a comparison. It's now on the list...

Apr 17, 2011 6:18 PM ET

Edited Apr 17, 2011 6:19 PM ET.

infiltration heat recovery
by j chesnut

You could be dealing with the shadow concept "infiltration heat recovery"

Doug, I know how this works in my house.
Just works during the wrong season ; )

Apr 18, 2011 1:41 AM ET

German OSB?
by Matthew Amann

Are the Germans using OSB?

Apr 18, 2011 10:36 AM ET

Euro OSB
by albert rooks


Yes. All of the German countries use OSB in (it appears to me) similar proportions to plywood as the US. Perhaps more OSB.

The Euro OSB is different in the following ways: 1, It's very smooth compared to US OSB. It cuts, feels and works closely to our plywood. I guess that's great for every application except when your sliding off a roof.... 2, it is formaldehyde free as is most all of the sheet goods these days. The spec sheets go as far a as rating it "fire safe". That's is not that it won't burn, but rates that it's contents are "safe to burn" for heat without causing health issues.

Bio mass heating is a big deal over there, so having "safe" sheet goods removes many health issues: manufacturing health, application health, recycle/compost or for fuel health. I've got to say... I'm trying not to be a total "euro nut", but what I see is impressive. it's hard to not respect and feel that some of these products methods could "fit" over here.

Not sure if that helped or hindered the point of your question...

Apr 18, 2011 10:58 AM ET

Edited Apr 18, 2011 11:03 AM ET.

ACH50 and heat loss
by Doug McEvers

j chesnut,

I think you are on to something with your inability to replicate your actual energy use with a heat loss program. Most energy geeks will be the first to admit a blower door test at 50 pascals does not represent normal conditions or typical leakage patterns for a given building. Far better would be tracer gas I believe, but that is getting quite scientific. We all know about the stack effect and how it works with common wisdom for air sealing saying, seal the high and low leaks first for the best efficiency gain. If you do this. many of the leakage points in the home like doors and windows are near the neutral pressure plane so on still days your infiltration heat loss could be far lower than a blower door test might indicate.

I spent 2 days in our attic air sealing before adding insulation and I also sealed the rim joist area in the basement. The attic insulation was upgraded to R-100 and the rim joist to R-20, R-10 Thermax was added to the interior basement walls. A new 95% furnace was installed and our gas usage for heating dropped from 1050 therms to 600 therms annually. The comfort was much improved and the energy savings seem greater than the sum of the parts would indicate, the ach50 for the house after air sealing is 3.14 or 1590 cfm50. The Btu/sf/hdd is 2.4, normal hdd is 7,876, the walls are 2x4 with fiberglass and 1" Styrofoam exterior sheathing, total sf is 3,328.

Apr 19, 2011 1:56 AM ET

by Matthew Amann

Thanks Albert, I just wondered about the OSB usage over there, I am sure it is not the same as ours, and ours is definitely NOT good for burning. Lots of formaldehyde in our stuff, that's why it stinks. If OSB was truly made from trash trees and recycling, then I would be a huge advocate. I know the truth is that they cut all of the Old Growth, planted plantations of same species, only so they can mow it down regularly and make panels and fiber boards. That is NOT sustainability..

Apr 20, 2011 6:06 PM ET

Why Fiberglass
by Allan Bullis, CEM, LEED AP

I do not understand why fiberglass is used instead of cellulose. It performs better, is less expensive and is a much 'Greener' product. It would be interested if they did some cellulose insulation and compare it to the fiberglass buildings. Also do not agree with the non staggered studs.

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