I’m looking forward to the new movies being released in December, particularly the next installment of “The Hobbit.” One film I doubt will be coming to a theater near you, though, is about urban pl
Passive House raises the bar
LEED used to be the buzzword for energy-efficient homes in the United States, but a new standard in town could be a game-changer: Passive House.
LEED used to be the buzzword for energy-efficient homes in the United States, but a new standard in town could be a game-changer: Passive House. This construction standard is the toughest one yet, requiring very low levels of air leakage, very high levels of insulation, and windows with a very low U-factor.
Are you ready for Passive House?If you’re getting involved in a Passive House project for the first time, here are a few things to consider:• Become a Passive House consultant. PHIUS offers both virtual and in-class training tailored to North American climate variations, market conditions, and building components.
• Invest in the software. The Passive House Planning Package (PHPP) is available for $225 from either PHIUS or the U.S. Department of Energy. The PHPP calculates energy demand for high-performance buildings. Among other things, the spreadsheet-based software provides data needed to determine a home’s heating and cooling loads and properly size its heating and domestic hot-water systems.
• Precertification is required while the home is still in the design phase. After construction is completed, a field test will be performed to ensure the home meets all parameters.
• Get ready for a learning experience, says CPHC Mike Duclos. “Think things through in the beginning, and have a good plan. If you can pull somebody into the team who has done one of these before, that’s a plus.”
“You maximize gains via passive solar heat gains and internal heat gains from mechanical systems and occupants, and minimize losses via a thick insulated building shell and a great airtight layer achieved through air sealing,” says Eric Barton of Biltmore Insulated Concrete, Highland Park, Ill., a CPHC and Passive House Institute US (PHIUS) Certified Builder who constructs super energy-efficient building shells. “This keeps the internal heat gains within the building envelope and living areas.”
Barton points out that because the specific space heat demand and specific primary energy demand requirements are the same for all climate zones, it’s easier to achieve Passive House standards in a mild climate, such as San Diego, than in a very cold climate such as Duluth, Minn.
Most builders say achieving the standard requires an additional upfront investment of 5-to-10 percent. But Falmouth, Mass., builder Christian Valle says, “The overall incremental costs are not as significant as one might think. The tradeoffs of building a tighter ‘mousetrap’ result in smaller HVAC systems, among other things, which help offset other costs.”
While Passive Houses are more challenging to build than standard homes, Valle believes that as more builders get on board, the learning curve will shorten. “The building industry has trended toward energy-efficient construction, driven by clients and more rigid energy codes,” he says. “Builders are paying attention to air-sealing and insulation details. That’s what Passive House is really about, in a nutshell.”
As the movement gains momentum, though, American window makers are going to have to up their game.
“We don’t make great windows in this country, but that’s starting to change,” Barton says. “Some manufacturers are stepping up to the plate.”
Reading, Mass., architect Steven Baczek collaborated with Duclos on the Massachusetts home featured here. Baczek laments that “nobody [in the U.S.] makes a cheap, triple-glazed, Passive House-certified window. Your window package is going to go from $20,000 to $45,000. On the other hand, $300 a year to heat, cool, and supply hot water for a 2,000-square-foot house is pretty amazing.”