Monday, August 2, 2010

Passive Houses Worth Examining to Save Energy

Green Building Elements

Having a housing world full to the brim with green energy options, running from many variations of wind power to solar geothermal and biofuels, one of the most effective and low-cost energy options exists is the simple passive house like the Boston home shown here by photographer Martin LaMonica on CNET.

Elsewhere, Nabih Tahan, in Berkley, California, is one of many architects who  has built a “passive house” that captures and recycles heat produced in the home. Bottom line: it eliminates the need for a furnace altogether.

Essentially this house and others like it is very well sealed, making forced air ventilation a necessity.  The heart of the system is a heat exchanger that strips the old, stale air of its heat and uses it to heat the incoming fresh air.  Tahan explains that this concept is best applied to new construction or to major remodels, due to the extensive sealing and insulation required.

“By doing smaller insulating renovations, you can improve energy consumption and you’ll definitely make a difference,” he said. “But to get to Passive House standards, you really have to either rip out the outside or the inside of the house.”

“This is not new technology,” writes reporter Doug Tapia in Our Green Streets blog.  He points out that the first passive house was designed and built in 1991 by German Physicist Wolfgang Feist, and today there are an estimated 15,000 passive houses worldwide, mostly in German speaking countries.  In Darnstadt, Germany, outside of Frankfort, Berthold Kaufmann’s house (shown in New York Times photo), “and others of this design get all the heat and hot water they need from the amount of energy that would be needed to run a hair dryer.”

By all accounts the technology is effective, rendering year round comfortable living at a tiny fraction of what it costs to heat and cool a traditional home, with no drafts, no thermostat lag and temperature stability.

“You don’t think about temperature — the house just adjusts,” said Mr. Kaufmann, watching his 2-year-old daughter, dressed in a T-shirt, tuck into her sausage in the spacious living room, whose glass doors open to a patio. He says his new home uses about one-twentieth the heating energy of his parents’ home of roughly the same size.

“This is a recipe for energy that makes sense to people,” Nabih Tahan said. “Why not reuse this heat you get for free?”

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Posted via email from David Bourbon