Log In


Reset Password
News Education Local News Nation & World New Mexico

A passive house is an efficient house

Some local builders adhering to tighter efficiency standards

Energy efficiency is a priority in varying degrees for some Durango homeowners, but a few local custom contractors are taking green building to an extreme.

Kevin Derheimer, a local engineer, lives in a house on County Road 250 that sits on foam. About six years ago, Derheimer began reading about passive building techniques.

“It doesn’t make sense how we typically build,” Derheimer said. “By building on concrete, we build ovens and use A/C to overcome that heat.”

So Derheimer built a house with Alpenglow Building & Design with photovoltaic panels, superinsulation (a roofing and walling technique that achieves airtightness) and a heat recovery ventilation system.

A passive house is one built to a rigorous set of energy-efficiency standards that originated in Europe. They require minimal energy to heat and cool, which is achieved through heavily insulated walls and foundations.

While the practice of passive home building is still catching on, particularly in the United States, the concept dates back to the 1973 OPEC oil embargo, which sparked an interest in energy-efficient building.

In the early 1990s, German physicist Wolfgang Feist and Swedish scientist Bo Adamson developed the design principles that define passive houses, the first of which was built in Darmstadt, Germany, in 1991.

Feist subsequently founded the Passivhaus Institute, whose techniques were introduced to the United States and inspired the founding of the Passive House Institute U.S. in 2007.

The practice has spread slowly.

Last week, Ecocor, a high-performance construction firm, announced a partnership with Richard Pedranti Architect, a company that designs sustainable homes, to offer clients an opportunity to build efficiently without sacrificing custom finishes, which is critical to Durango’s passive-home buyers.

For Alpenglow, interest in passive homes traditionally comes from high-end buyers, said Ben Fisher, a company partner and lead carpenter.

Alpenglow became PHIUS certified in 2014; Derheimer’s house is the third high-performance project of its kind that Alpenglow built. Fisher said the company spends $250 to $300 per square foot (the national average is about $125) on these projects, but some of that cost boils down to aesthetics.

“It does cost more up-front, but a lot of the costs of high-end passive homes have nothing to do with the passive system,” Fisher said. “It has to do with design, size and the customization – real, hardwood floors, high-end lighting.”

Because once built, the home begins to recoup costs on heating and cooling. Derheimer’s house has triple-pane windows, a ventilator with a heat exchanger, and its foundation is foam, which all prevent cool air from leaking out in summer and warm air from leaking in winter.

Because passive building is foundational and not cosmetic, Alpenglow’s passive houses are new construction, though Jacob Bleth of Durango Green Homes has retrofitted some existing housing stock.

“What we’re trying to do is lessen people’s energy costs up to almost eliminating them altogether,” Bleth said. Durango Green Homes follows net zero building principles, which means the house has zero net energy consumption, or energy used by the structure is equal to the renewable energy it produces.

Bleth has built homes for 10 years in Durango, with his first house built on passive principles underway this summer.

“We start with a superinsulated, airtight structure,” he said. “And daylight is factored into the design plan so that every room used in the day has a window, so you don’t have to turn on a light. And we orient the building to the south, which offsets heating costs.”

But passive building has not entered the mainstream, and there are few builders in Durango that build to those standards.

“There are some builders who specialize in that, but we really don’t come across them very often,” said Paul Beasley, president of the Home Builders Association of Southwest Colorado. And the market traditionally excludes the low-end and mid-range buyers. The estimated cost to build passively, depending on the house, is an additional 5 to 20 percent.

“So far, the passive houses we’ve done are in the higher-end, but that’s not to say they have to be,” Fisher said. “It’s unfortunate because the other markets are the ones that would benefit most.”

jpace@durangoherald.com



Reader Comments