Geothermal or air-source? Indy experts explain differences
What are the differences between air-source heat pumps and ground-source heat pumps? — Angie's List member Mark Schinman
The main difference is where each system draws heat from, says Isaac Brewer, owner of highly rated Brewer Heating & Cooling in Greenwood, Ind. "Your air-source pump pulls out heat from the outside air," he says. "Ground-source, or geothermal, pumps pull heat out of water circulating in pipes underground, which is consistently around 50 degrees." For cooling, both pumps remove heat from indoors.
Mike Hoagland, a manager at highly rated Airtron Heating & Air Conditioning in Indianapolis, says both pump types deliver better efficiency than conventional HVAC systems, but geothermal offers much more efficient performance. The drawback, he says, is cost. "Geothermal is much more expensive, but if you're staying in a house for a long time, there can be a significant return in lowered operating costs," he says. Depending on installation conditions and options, Brewer estimates an average air-source pump costs between $5,000 to $10,000; a geothermal system can cost as much as $12,000 to $20,000 or more.
Hoagland says both pump types typically utilize electric backup heat when temperatures become too cold to produce efficient pump performance. He says investing slightly more in a dual-fuel air-source pump, which uses a gas-fired backup furnace, will offer greater backup efficiency.
To offset the high upfront cost, Brewer says geothermal systems installed before 2016 can qualify for a federal tax credit of up to 30 percent.