Aiming to popularize energy efficient construction in North America, a building certification group has overhauled its rigorous German-based energy standards to make them more cost-effective for the American market.
The move is expected to “accelerate uptake” of passive house design, which emphasizes super-insulation and airtightness, said Katrin Klingenberg, executive director of the Chicago-based Passive House Institute U.S. The approach is used for schools, commercial buildings and apartments, not just houses.
So far the group counts 125 certified projects in North America, far fewer than in Europe, where higher energy costs offer greater incentive for energy efficiency.
Graham Wright, an engineer who led the committee that developed the new standards, noted that the German rules have been tweaked in other countries such as Sweden. But the U.S. changes are more sweeping. “We are now going into the standard-setting business,” he said.
Wright called the overhaul an effort to “re-Americanize” passive house, a design approach developed in Germany but based on U.S. building science research conducted during the 1970s energy crisis.
It dovetails with the U.S. Department of Energy’s recent Zero Net Energy initiative, which is pushing for all homes and commercial buildings eventually to generate at least as much power as they consume. The agency partnered with PHIUS in crafting the voluntary new standards, along with leading U.S. building scientists. They are slated to launch in January following DOE and public review.
Still in place are three benchmarks established by the German Passive House Institute: airtightness, limits on annual heating energy, and limits on total annual energy use. But the new benchmarks vary for each U.S. climate zone. For example, more heating energy will be allowed for buildings in cold climates such as Minnesota with lower limits for warm zones such as California. They add an allowance for energy needed to dehumidify spaces in subtropical regions.
The fine-tuning addressed a range of factors including Americans’ avid use of lighting and electric appliances. Wright said as a country, “We should be using less, but we’re not certifying occupants.”
Cheaper solar panels and the relatively short life cycles of U.S. buildings were also weighed. “It’s important to have credibility as to the current reality, at least for the next generation,” Wright said.
Passive house is still a relatively new concept in North America. The first certified U.S. project was completed in 2003 in Urbana, Ill., and PHIUS was founded in 2007. It’s captured the attention of American architects, engineers and builders who are hungry for guidance on energy-efficient design. Today the group has 16 chapters and more than 350 members. It’s trained more than 1,500 professionals including 550 certified passive house consultants and 150 certified builders.
But those eager designers and builders face a skeptical marketplace, where a perception often holds that passive house projects are more expensive than standard construction, even if they do save energy down the road. Crafting a new consumer message around quality was a recurring theme at PHIUS’s annual conference in the Bay Area over the weekend.
Sam Rashkin, chief architect in the DOE’s Office of Energy Efficiency and Renewable Energy and an advocate for retooling the U.S. housing industry, said efficient buildings should be marketed on health and comfort, not just energy savings. Passive houses, for example, have clean air from constant ventilation that can reduce the symptoms of asthma. Their thick insulation and triple-glazed windows buffer occupants from street noise.
“The consumer experience living in these homes just blows away any other home,” Rashkin said. “That’s like having a car that gets 100 miles per gallon. (It’s) hard to give up once you have it.”