Energy-saving passive housing, something of a “bubbling under” trend to many, seems to be gathering momentum, including in Fairfield County where a pair of developers are rolling out the concept to both residential and commercial customers.
“A passive house is by far the most energy-efficient building in the world,” said Salvatore Zarrella, founder of Construction Management Group (CMG) in New Canaan. “It’s changed the way we put houses together.”
“I’ve had a special interest in green building for a long time,” said Mike Trolle, who is the founder and, with his brother Chris, co-owner of BPC Green Builders in Wilton. “Once I learned more about passive housing, I realized that this really is the future of development and construction.”
What has stoked the enthusiasm of the builders — both of whom continue to build nonpassive homes as well — is what CMG partner Michael Block calls “the highness standard of energy-efficient building, (which) requires virtually no energy use for heating or cooling.”
The concept, which originated in 1988 as “passivhaus” in Germany, includes continuous insulation throughout the building without any thermal bridging; air-tight construction, which prevents infiltration of outside air and loss of conditioned air while providing better air quality within the building; high-efficiency windows (usually triple-paned) and doors; and an efficient whole-house heat- and moisture-recovery ventilation system.
Although the cost of a home certified by the Passive House Institute U.S. can be more than that of a “regular” house, the builders said that upfront costs are mitigated to heating and air conditioning. “Generally, for a 2,500-square-foot passive house, you’re looking at spending about $500 to $800 a year,” Block said. “Most people spend that much per month. And that’s just for heating and cooling.”
Electricity, Zarrella said, “You’re basically using the same amount as you would with a hair dryer.”
Trolle, whose own home in Danbury is a passive design, said his annual energy cost is roughly $360 per year. The home’s indoor temperature is set at 70 degrees, he said, and remained steady even when temperatures dropped to minus 12 degrees in winter. Removing the necessity of constantly monitoring and adjusting a home’s temperature is what “passive” is all about, Trolle said.
The template is applicable to any size and style of building. “If you Google ‘passive house,’ you’ll see a lot of boxy, European style homes, but it doesn’t have to be that,” Block said, noting that one of CMG’s two passive homes in a North Stamford subdivision is a traditional farmhouse, while the other is done in the modern style. The company is planning two more homes in New Canaan, he said.
Work is also ongoing at what will be the world’s tallest building to employ passive housing standards, Block said, referring to Cornell Tech’s 26-story residential building on Roosevelt Island in New York City. Once completed, it will feature 350 units to be used by both students and faculty at the technology-focused campus.
Both firms expect passive housing to be a game-changer in the industry. “More and more, people are interested in being on the green side of things,” Trolle said. “Here you have something that’s durable, that can improve the health of the residents, and is about as energy-efficient as you can get.”
His company has completed two homes certified by the Passive House Institute: a colonial in Watertown and Trolle’s own cottage in Danbury, which was the first house in the state to earn the certification. He expects business to expand over the coming years.
“The people who find us usually have done a reasonable amount of research,” Trolle said, noting that “green” is in the company’s name. “But while a lot of them are interested in something that’s green, they may not necessarily want to get the PHIUS certification, which can cost several thousand dollars.”
“Awareness of passive housing is growing exponentially every year,” Block said. “It’s exploding in Brooklyn,” where a number of brownstones are being retrofitted to the passive standard, “and will quickly start bleeding into the suburbs of New York City and into Fairfield County.”
“There’s already a lot of talk among builders about the passive housing standard,” added Zarrella. “It makes a lot of sense, both for the customer and the environment. There’s really no disadvantage to doing it.”