An Introduction to Geothermal Heat Pumps

Geothermal heat pumps have been in use since the late 1940s. Geothermal heat pumps (GHPs) use the constant temperature of the earth as the exchange medium instead of the outside air temperature.

While many parts of the country experience seasonal temperature extremes—from scorching heat in the summer to sub-zero cold in the winter—a few feet below the earth’s surface the ground remains at a relatively constant temperature. Depending on latitude, ground temperatures range from 45°F (7°C) to 75°F (21°C). Like a cave, this ground temperature is warmer than the air above it during the winter and cooler than the air in the summer. The GHP takes advantage of this by exchanging heat with the earth through a ground heat exchanger.

As with any heat pump, geothermal and water-source heat pumps are able to heat, cool, and, if so equipped, supply the house with hot water. Some models of geothermal systems are available with two-speed compressors and variable fans for more comfort and energy savings. Relative to air-source heat pumps, they are quieter, last longer, need little maintenance, and do not depend on the temperature of the outside air.



Heat pumps generate heat in four different ways.

Vertical Ground Collectors
This System uses the heat in the earth below your house. The heat pump pumps the water vertically down into the ground and the water is heated by the earth.

Horizontal Ground Collectors
This System uses a loop of water pipes buried 6ft under the surface of your garden. The heat from the ground heats the water in the pipe and a pump circulates the water to the house. The heat is extracted from the soil by means of buried plastic tubing.

Air Source Collectors
This system uses the Air around us to generate heat for your home. The air from around your home is sucked in by the heat pump and compressed

Water to Well Collectors
This system uses the warmth in the water deep within your well.