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Geothermal heating and cooling systems are gaining acceptance in residential construction here, although most adopters of the heat-transfer technology are in the upscale custom home market.
Jeff Fountain, a principal at Copeland Architecture & Construction Inc., a Spokane designer and builder of custom homes, says about a fourth of the company's customers are interested in geothermal systems.
"It's a real good way to lower monthly costs," Fountain says, although he adds that upfront costs are higher than for conventional gas and electric systems.
Geothermal systems employ a basic heat-exchange technology that's loosely similar to conventional air-conditioning technology. Geothermal systems, however, usually are reversible, meaning they can heat as well as cool.
When in the cooling mode, a residential geothermal system uses a ground-source heat pump to pull heat out of a home and radiates it through an underground coil system, similar in concept to the above-ground coil system in an enclosed unit. The coil component in a geothermal system consists of several hundred feet of tubing or pipe that's looped at least six feet underground, where ambient temperatures are constant.
When a geothermal system is in the heating mode, the process is reversed and the ground-source heat pump draws heat from the ground and transfers it to the residence.
Geothermal systems exchange heat using a small amount of energy, while conventional natural gas systems produce heat by burning fuel in a furnace or boiler....