Geothermal heat pumps

Geothermal heat pumps (GHPs) also referred to as GeoExchange, ground-source or water-source heat pumps, have been in use for oveer 70 years. They work on the principle of using constant earth temperature as the medium for the exchange. With this system they reach efficiencies as high as 600% on the cold winter days as compared to 250% maximum efficency for air-source heat pumps.

Biggest parts of United States throughout the year experience scorching heat to sub-zero cold, but below the earth's surface the temperature remains constant. 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 cool, heat and also supply the house with hot water (if heat pump system includes this option). Some models of geothermal systems are available with two-speed compressors and variable fans for saving even more energy. Relative to air-source heat pumps, they don't need a lot of maintenance, are quiet and last longer.

 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. The main advantage of dual-source systems is that they cost much less to install than a single geothermal unit, and work almost as well.

Even though the price of a geothermal system can be higher than that of an air-source system, the costs are returned to you in terms of energy savings in 5 to 10 years. System life is estimated at 30 years for the inside components and 50+ years for the ground components (loop). There are approximately 100,000 geothermal heat pumps installed in the United States each year. For more information, so think carefully when deciding what is the best option for your heating and cooling system.

Mike.