In Reisterstown, as a couple builds a 4,000-square-foot cedar and stone contemporary house on three acres, a crater at the site looks as if it might swallow an Olympic-size swimming pool.
Instead, it ingests a healthy helping of copper ground coil, a key element of the home's geothermal heat pump -- a heating and cooling system that builders and utility companies say can save consumers hundreds of dollars a year in utility bills.
Across the country, utilities are testing geothermal units, and some, including ones in New York, New Jersey and Virginia, are now offering rebates to builders and homeowners who install them, according to Ed Barbour, a mechanical engineer for the Bowie research center of the National Association of Home Builders.
Baltimore Gas & Electric Co. does not offer rebates specifically for geothermal heat pumps, though it does offer rebates for energy-efficient systems, which could include geothermal units.
"We're aware of the technology," BGE spokesman Charles Franklin said, "and we're loosely in a study phase now. But we haven't made any commitments."
Pridemark Custom Homes -- which built the house in Reisterstown -- says it is the first builder in the Baltimore area to offer geothermal heating. Pridemark, based in Millersville, expects to build about 50 homes this year, and is now installing its second geothermal unit.
The Long Island Lighting Co., a New York utility, estimates that a family of four can reduce utility bills 30 percent with a geothermal system. It projects that heating and cooling a 2,000-square-foot house would cost $961 a year with a geothermal heat pump. To heat and cool the same house with oil or gas, using conventional air-conditioners in the summer, would cost $1,291 or $1,272, respectively. An air-to-air heat pump, which both cools and heats, would cost $2,149, including supplementary electric heat. electrical heating system, plus air conditioning, would cost $2,218.
USPower Climate Control Inc., the Allentown, Pa.-based manufacturer that built the system for the Reisterstown home, estimates that most homeowners will save about 30 percent on their heating bills -- or about $75 per month.
Another couple, Jay and Charlene Simonds of Reisterstown, installed a geothermal heat pump in their $230,000 new home. Even in the record-setting cold of last winter, the electric bill for the 3,900-square-foot home was about $165 a month, Mr. Simonds said.
