Geothermal Heat Pump Efficiency

Whether you are anticipating new construction or replacing your current HVAC (Heating, Venting, and Air Conditioning) system you should consider a Geothermal Heat Pump. You will need to have ample yard space to accommodate several wells that are dug for circulating water to absorb the ground source temperature.

Geothermal Heat Pumps (GHPs) have been around since the late 1940’s. They use the constant temperature from the earth as the exchange medium rather than the exterior air temperature. This enables the system to achieve relatively high efficiency on the coldest of winter nights compared to air-source heat pumps. They are also known as ground source, GeoExchange, Ground-Source, or Water-Source heat pumps.

While many regions of the country experience seasonal temperature extremes from broiling days in the summer months to friged days in the winter months, we find relatively constant temperature a few feet below the earth’s surface. Depending on latitude, ground temperatures range from 45°F to 75°F. The ground temperature is warmer than the ground surface or air during the winter and cooler in the summer. The GHP takes advantage of this by simply exchanging heat with the earth through a ground heat exchanger.

Much like any heat pump, geothermal heat pumps are able to heat, cool, and, can also supply the house with hot water. Some models of geothermal systems are offered with two-speed compressors and variable fans for much more comfort and energy savings. Relative to air-source heat pumps, they are more quiet, last longer, need little maintenance, and do not depend on the temperature of the outside air.

A dual-source heat pump combines an air-source heat pump with a geothermal heat pump. These appliances combine the best of both systems. Dual-source heat pumps have higher efficiency ratings than air-source units, but are not as efficient as geothermal units. Dual-source systems cost much less to install than a single geothermal unit, and work almost as well.

A Geothermal Heat Pump will cost several times more to install compared to that of an air-source system, all components being equal. Depending on electrical rates in your area, the additional cost of installation will be returned to you in energy savings in approximately 5 to 10 years. The life of a Geothermal Heat Pump is estimated at 25 years for the inside components and 50 years for the ground loop.

The equipment will be labeled with the rates of efficiency that are measured by HSPF (Heating Season Performance Factor) for heating and SEER (Seasonal Energy Efficiency Ration) for cooling.