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
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!
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.”
- Martin Holladay
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