Healthy Homes; New building technologies and innovative add-ons are making nearly-zero-energy houses a real possibility.(Cover Story)

Byline: William Underhill and Malcolm Beith (With John Sparks in New York Graphic by Stanford Kay)

Imagine a community for the deeply green. Walls half-a-meter thick keep temperatures comfortable year-round. Windows are triple-glazed. A wind-driven ventilation system feeds fresh air into each house--and grabs the heat from stale outgoing air. Outsize conservatories face south to trap the light and warmth of the sun. Most of the energy-saving technology isn't flashy, though solar panels do provide enough power to run the community's pool of electric cars. The architecture is modish and even the most modest apartment has its own garden. Of course, residents enjoy an organic-vegetable delivery service, too.

This might sound like a limousine-liberal fantasy--the kind of high-tech oasis where the superrich can soothe their consciences deep in the woods. But it's actually an 84-home development, called BedZED, on the site of a disused sewage-treatment plant in an unfashionable patch of South London. Its residents aren't well-meaning ecozealots: many are tenants of a housing charity. But they are all at the forefront of a global trend toward reducing energy consumption in the home.

In Europe and America, buildings guzzle around 40 percent of all energy--about 10 percent more than transport--and create the same proportion of carbon-dioxide emissions. As the world adjusts to life without cheap hydrocarbon fuels, improving energy efficiency across the board is going to be essential. BedZED and other initiatives show that trimming excess energy consumption needn't be difficult or even high tech--just a matter of intelligent design. "People are sick and tired of environmental campaigners' presenting doom-and-gloom scenarios without offering solutions," says BedZED architect Bill Dunster.

The key is finding ways to maximize efficiency in the simplest ways possible: the "zed" in BedZED stands for "zero energy." Whatever little juice the London homes need after taking advantage of their built-in energy-savers comes from an on-site power plant, fueled by waste timber. Simple also means cheap; build 5,000 Zedhomes, says Dunster, and the economies of scale mean the cost is no more than that of constructing a normal home: the price of components tumbles as production numbers rise. It's no wonder such ideas are gaining admirers. Over the past two years, BedZED has attracted thousands of visitors from as far away as India and China. In the fall, Dunster's company, ZedFactory, begins work on two separate projects elsewhere in Britain. In the United States, zero-energy communities have been constructed from Elk Grove, California, to Loudoun County, Virginia, spurring interest among forward-thinking builders and homeowners alike. "Once people know about it, they want to live there," says David Meisegeier, an energy-efficiency specialist at Virginia-based ICF Consulting. "Who wouldn't?"

The technologies could already be used much more widely. Things like triple-glazing windows to add extra insulation, tightening duct systems and using structural insulated panels for floors and walls are easy and cost-effective--and could cut the fuel consumption of the world's buildings by 20 percent by 2010. "You can accomplish a tremendous amount with the technologies that we have already," says Randall Bowie, a Swedish official working on energy efficiency for the European Commission in Brussels. Take today's domestic boilers, which are generally 30 percent more efficient than the previous generation--or new refrigerators in the U.S. market that use 75 percent less electricity than those from the 1970s. Even simple gadgets like programmable thermostats or light timers noticeably decrease energy use and costs. "This is about doing a lot of unglamorous stuff," says Andrew Warren of the European Alliance of Companies for Energy Efficiency in Buildings.

Major momentum for these ho-hum changes has come from European governments worried by threats to energy supplies and the need to meet energy-reduction goals agreed to under the Kyoto accords. They've started to issue grants and tax breaks for energy-efficient builders, as well as stricter regulations. The standards set by national building codes are ratcheting up, and an EU directive that takes effect at the end of next year will ...