Geothermal heat pumps (GHPs) use the earth or a water body to heat and cool your home. Ground source heat pumps use the ground for a heat source and water source heat pumps use a water body as a heat source. Both are classified as geothermal heat pumps, which work like refrigerators by moving heat from place to place. The heat pump moves heat from the earth or a water body to indoors in winter and from indoors to outdoors in summer.
The more common air-source heat pumps take heat out of the cold winter air to heat your home. This only works down to an outdoor temperature of around 40?F. GHPs take advantage of the earth’s constant temperature to provide home heating more effectively than air-source heat pumps and three times more efficiently than electric-resistance heat. This ground heat is extracted from a large loop of piping buried in your home’s yard.
Installing a ground-source heat pump requires an experienced contractor with knowledge of the sizing and installation of the ground piping. Though the initial cost of installing a GHP can be around double that of traditional heating and/or cooling systems, the benefits are many. GHPs can reduce energy consumption by up to 45% compared to air-source heat pumps and up to 70% compared to electric resistance heating with standard air-conditioning equipment.
A GHP can provide free hot water during the summer cooling season as excess heat is transferred to the hot water tank. In the winter, water-heating costs are roughly cut in half.
GHPs allow for design flexibility and can be installed in both new and retrofit situations. GHPs are also quieter than conventional systems because there is no noisy outdoor condensing unit. GHPs offer improved humidity control, making your home more comfortable in hot humid weather.
Finally, GHPs require less maintenance than conventional systems. Because all the piping is underground or underwater, there is very little required maintenance. Occasional cleaning of the indoor coil and regularly changing the air filters are about all that’s necessary to keep the system running well.
If you’re building a new home or considering a new heating or cooling system, it may be well worth it to invest a geothermal heat pump to permanently reduce heating and cooling costs.
See The Homeowners Handbook to Energy Efficiency or Residential Energy: Cost Savings and Comfort for Existing BuildingsChapter 6 for more information. For professional information about heating systems and energy efficiency.