Ground-source heat pumps have been around for decades but every year seem to attract more homeowners and organizations who are looking for alternatives to traditional space heating and cooling. They can hook into existing forced hot air and hot water systems but not steam heat.
Starting in 2006, nearby Harvard University installed six ground-source heat pumps as part of its Green Campus initiative. Administration buildings and athletic facilities are already online and two more buildings planned.
People who go with geothermal are typically either interested in it because it's a clean energy technology or because they're looking to escape fossil fuel prices, said Diona Roberg, the director of operations at Water Energy Distributors, which distributes geothermal systems from ClimateMaster.
"Business is out of control--we can barely keep up with it," Roberg said. About half of the customers go geothermal to cut heating and cooling costs. But the other the half "don't care what it costs, they just want to do green," Roberg said. The family-owned business has doubled in size over the last four years.
Open and closed loop
Strictly speaking, what's often called a "geothermal system" is a misnomer because it implies tapping the heat in the Earth, something already done at large scale to supply electricity to utilities. This geothermal energy--and its offshoot enhanced geothermal--works only works in certain geographies and uses different technology.
Strictly speaking, what's often called a "geothermal system" is a misnomer because it implies tapping the heat in the Earth, something already done at large scale to supply electricity to utilities. This geothermal energy--and its offshoot enhanced geothermal--works only works in certain geographies and uses different technology.
Regardless of type, though, ground-source heat pumps are considered one of the most efficient forms of heating and cooling.
The International Ground Source Heat Pump Association, based in Stillwater, Oklahoma, said geothermal is 50 percent to 70 percent more efficient for heating than other systems. The U.S. Department of Energy says that a ground-source heat pump uses 25 percent to 50 percent less electricity than conventional heating and cooling systems.
Roberg said that the maintenance costs for geothermal are half the cost of traditional heating and cooling systems. The payback on geothermal systems, which used to be about seven years, is now typically four years, she said. Recently passed federal renewable energy incentives now include $2,000 per year tax credit.
"Even though heat pumps and geothermal space conditioning has been around for a while, it's still considered very much a new market and as such, there aren't nearly enough contractors and engineers," he said, adding that an installation can require coordinating different contractors. "Unfortunately, until you have a one-stop-shopping solution, it's not going to become nearly as ubiquitous as it could be."
