Baltimore City and Carroll County offer no tax credits, and Baltimore County offers them only for new homes, said Don Mohler, a county spokesman.
Daniel Ellis, president of the nation's largest manufacturer of geothermal equipment, said he believes that recent huge and sudden energy market fluctuations have convinced more people they'd be more secure with an independent heating and cooling system.
"People believe that anything that can go up that easily and go down that easily can go up again," he said, referring to last summer's spike in oil prices.
"All it takes is one storm in the Gulf" of Mexico to disrupt the oil market, said Ellis, president of Climate Master Inc., of Oklahoma.
Ellis said his business doubled from 2005 to last year, even before federal tax credits became available. Now, with no ceiling on federal credits, which cover up to 30 percent of the cost of whole-house geothermal or solar systems, the industry was up 40 percent in the first four months of this year, he said.
Solar systems are prospering too, according to Monique Hanis, spokeswoman for the Solar Energy Industry Association in Washington. Whole-house solar electric systems increased 81 percent in 2008, and smaller solar hot-water system installations went up 50 percent, she said. The federal credit program has given the industry a higher profile, she said. "More people are aware of it."
Maryland companies similarly report increased business. John Love, whose Severn company installed the Barney-Parcells' system last winter, said that despite the recession, he bought a new truck for his business and hired two more workers to keep up.
"In two years we've increased our residential business 50 percent. It's pretty dramatic," he said.
Barney said Love's firm hired a drilling firm to install a 450-foot-deep well for the geothermal pipes filled with an alcohol-based solution near their 2,300-square-foot home, built in 1972.
The major part of the system is invisible under the grass of the couple's verdant quarter-acre front lawn. In the basement, two water tanks sit side by side, attached by pipes and metal ducts to the fan and heat pump portion of the system. Love said the unit produces hot water in the first tank as a byproduct, and that is used to cut the cost of the household hot water tank by up to 75 percent. Since the rancher had baseboard heat, Love installed metal air ducts in the basement ceiling, joining them with ducts installed for central air conditioning.
