Above the ground we can expect to experience dramatic temperature changes throughout the year. However, just a few feet below the Earth's surface the temperature remains more constant at around 50 to 60 °F. A geothermal heat pump takes advantage of these more mild temperatures through a series of pipes and a heat exchanger.
In winter, when ground temperatures hover around 50° F, these systems pump fluid underground through a series of buried pipes, called a loop. The fluid becomes naturally heated, circulates back into the home, and an electrically driven compressor and heat exchanger concentrate the Earth’s energy and releases it inside the home at a higher temperature.
In summer, the process is reversed. The underground loop draws excess heat from the house and allows it to be absorbed by the Earth. The system cools your home in the same way that a refrigerator keeps your food cool - by drawing heat from the interior, not by blowing in cold air.
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. They are smaller than a traditional heating/cooling unit and can easily be retrofitted into any home.