Home Appliances Help to Heat Local 'Passive House'
Passive House EngineeringNabih Tahan, a Berkeley architect, explains the theory behind a "passive house", which is engineered to minimize the energy required to stay heated.
Thursday, December 4, 2008
Category: News > University > Research and Ideas
A self-heating house may sound like something out of science fiction, but a Berkeley homeowner has turned that fantasy into reality with his newly renovated home.
The residence is the first in California to use the Passive House system, which originated in Germany and is designed to use heat produced from running appliances to warm the house.
"With this system, you can reduce your use of conventional heating by 80 to 90 percent," said Berkeley architect Nabih Tahan, who owns the Passive House on Grant Street.
In order for the system to work, the house must be so well insulated that nearly no air can escape the building on its own, Tahan said.
Tahan explained that "free" heat produced by household appliances is carried by air inside the house to an energy recovery ventilator, which blows the air outside, but not before transferring the heat contained in the outgoing air to incoming fresh air.
On the low setting, running the ventilator is roughly equivalent to running a toaster. Running the ventilator on high uses about double the amount of electricity, Tahan said.
While the idea of a house that heats itself almost solely without the use of fossil fuels is environmentally attractive, the cost to remodel a home to fit the Passive House insulation standards is financially daunting, said Kathleen Matthews, mechanical designer for Taylor Engineering, a Bay Area environmental engineering company.
"I could see the system coming into a new house, but to remodel would just be so expensive," Matthews said. "You would have to change pretty much every component of the house."
It is most practical to use the Passive House design when constructing new buildings or remodeling homes that need drastic renovations, Tahan said.
"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."
The Passive House Institute U.S. is trying to adopt the German Passive House system to the warmer climate of California, said Corey Fitch, program associate for GreenPoint Rated, a program within Bay Area-based Build It Green.
But because California is much warmer than the European countries where the Passive House system originated, the payback may not be as great, Matthews said.
"Bottom line, it would be really hard to get your money back," she said.
Though the Passive House design may not be the standard for future net zero energy consumption homes, UC Berkeley lecturer of city and regional planning Vicki Elmer said this technology is promising.
"Houses like this are the wave of the future," she said. "It's time to start thinking creatively about heating and ventilation systems in order to minimize energy use."
Mai Fung covers environmental issues. Contact her at [email protected]
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