Warm Up to Geothermal

Instead, the secret gets buried. Literally, in the backyard, where drillers might sink several holes deep into the ground for a system that sucks heat out of the earth in the winter and cold in the summer. It's tried and true, can cut utility bills by half, and does away with noisy air conditioning condensers by the back patio. "It's a no-brainer," says Jim Damiani of Edmond, Okla. He helped run two big companies—Lennox and York, which make conventional HVAC systems, and has installed geothermal in his last two homes.

Yet lots of people with brains stick with the conventional. Less than 1 percent of U.S. homes has geothermal systems, and that's decades after the technology emerged as a proven energy saver. The biggest hurdle is the upfront price. A geothermal system can cost twice as much as a new conventional gas or electric system. The difference is in those holes. Drillers might need four 150-foot holes for a typical suburban home. Then a loop of plastic pipe is inserted, covered with dirt, and hooked to inside gear that looks much like conventional furnaces. The inside units pump water into the ground, causing it to emerge at a constant ground temperature, typically about 55 degrees Fahrenheit. That's obviously enough to cool a house in the summer, and compressors can eke out enough heat for almost all but the bitterest winter days. Supplemental electric heat helps on the coldest days.

Buyers' advantage. To get their money back, homeowners might need to stay in the house at least three years, and maybe as long as 10. Or they need a buyer who understands the advantages. Appraisers, at least, have started to add value to homes with geo-thermal systems, but not many real-estate agents and builders have joined the parade, says Daniel Ellis, president of ClimateMaster, which makes geothermal systems. He says builders don't let homeowners choose a lot of the big stuff, like heating and cooling. "They'll just ask about the granite and flooring."

Or the technology needs a significant tax break, which so far Congress has not granted. The feds haven't ponied up partly because geothermal, unlike other green technologies, is a proven profit maker. "It's already a sweet deal," says Jim Bose, whose group at Oklahoma State University researches geothermal and trains contractors. "How sweet a deal do you need?"