In a nation recognized for its obsession with efficiency, it’s no surprise that Germany is jumpstarting the rise of an aggressively energy-efficient trend in home building: “passive houses.” In a recent New York Times article, part of the paper’s The Energy Challenge series, readers are welcomed into the ordinary looking Kaufmann home in Darmstadt, Germany, on a cold and bleak day. Inside, there is no furnace burning (there’s actually no furnace at all) and the Kaufmann clan is dressed comfortably sans sweaters and heavy wool socks.
What's going on here? A Teutonic variation of the Twilight Zone about pod people desensitized to the cold? Not quite. The Kaufmann’s live in one of 15,000 passive houses existing around the world, most of them in Europe (one of the first in the US is being completed in Berkeley, California).
So what exactly is a passive house? It’s a building -- modest in size -- that’s been built to recycle heat. A passive house is constructed with innovative doors, windows, and insulation that prevent cold air from coming in and heat from going out. There are usually no heating systems (there's an emergency generator in chez Kaufmann). I mentioned the word pod earlier. A passive house isn’t too dissimilar to one: The home’s heat is generated primarily from the sun but also from the use of household appliances and from the bodies of those living inside of it.
A bit strange, I know, and also an idea that strikes me as a bit stinky (not too mention stuffy). What happens to all the smells produced in an airtight home? Can a window in a hermetically sealed room be cracked after a garlicky dinner followed by cigar smoking? To eliminate stagnant air, passive houses feature progressive central ventilation systems: warm air going out passes side by side with clean cold air coming in. The cold air and hot air exchange heat with 90 percent efficiency. And, of course, windows can still be opened.
These extremely energy-efficient and increasingly popular houses (at least in Germany, home to the Passivhaus Institut
) are also affordable to build, their construction not costing much more than a “normal” home. Passive houses cannot be constructed just anywhere -- like an area with little sunlight and extreme hot and cold -- since they require collaboration between the sun, the climate, and the building itself. And due to their compact, airtight design, passive houses cannot be rambling mansions with square footage equivalent to a city block.
And since all good German design eventually makes its way overseas, an interest in passive houses is growing in the US. However, setbacks in technology and cost could keep this movement slow moving. There’s also probable resistance from those who may find a home with completely uniform air and temperature a bit disorienting (I’m one of them).
I’ll continue to track this innovative green building movement as it develops stateside. Can’t say I’d love call a passive house home as I enjoy the shock of a cold room during the wintertime every so often. However, the shock of an outrageous heating bill in January is something I could definitely live without.