Geothermal heat pumps efficient but more expensive
What are the differences between air-source heat pumps and ground-source heat pumps? — Angie's List member Mark Schinman
A ground-source (geothermal) heat pump uses tubing buried underground to take advantage of the earth's consistent temperature; air-source pumps draw heat from outside air, according to Bob Clement, owner of highly rated Deljo Heating & Cooling in Chicago. "An air-source pump has more moving parts inside and outside. With ground-source, all the mechanical equipment is inside the house," he says.
Both types of heat pumps are considered to be energy efficient compared to conventional models, but ground-source pumps are more efficient, says Brian Leith, owner of highly rated Leith Heating & Cooling in West Dundee [Ill.]. However, they're also more expensive.
"You're looking at about three times more upfront for a ground-source pump," he says. "A ground-source pump can run up to $30,000. But you also don't have to use the backup source as much. When an air-source pump gets below a certain temperature, it needs a gas or electric heater to kick in. The ground source pump is more stable, since it's not affected by the ambient air temperature."
Clement says ground-source pumps aren't possible for all Chicago properties, since not every site has the space necessary to drill or excavate well source. "But when there's room, it's the way to go," he says."
According to the U.S. Department of Energy, geothermal systems installed before 2016 are also eligible for a 30 percent tax credit.