Geothermal heat pumps or GeoExchange have been used in homes since the 1940s. This type of heat pump is earth-coupled, water-sourced or ground sourced. This type of heat pump uses the temperature of the ground or water as a means of collecting or exchanging heat instead of using the air as a means of collecting or exchanging heat. Since the ground and water holds a steadier temperature than air does, this type of heat pump is 300 percent to 600 percent more efficient than an air-sourced heat pump especially on a bitterly cold winter day.
There are temperature extremes all over the world. In some places the summer sees excessively high heat and in other regions winters are bitterly cold reaching well below zero. These temperature extremes really only exist on the earth’s surface, and just a few feet below the ground the temperature of the earth stay fairly consistent most of the time. Depending on the area of the world, the ground temperature can range between 45 degrees Fahrenheit to 75 degrees Fahrenheit. This is in some ways to the temperature experienced in caves. In the winter a cave is warmer than the air outside the cave, but in the summer, the opposite is true. The air inside the cave is cooler. A geothermal heat pump uses this consistency as an advantage by exchanging the heat in the ground to use within an interior space.
Geothermal and water-sourced heat pumps are able to do the same things that other heat pumps can do such as heat, cool, and supply hot water in some cases. There are a variety of geothermal heat pumps available. Some have two compressors and a variety of fans to provide more energy savings and more comfort. In many cases geothermal heat pumps are quieter, have a longer life, require less maintenance, and draw from a more consistent temperature source than their air- based counterparts.
There are some models that combine a ground-source with an air-source heat pump. This type of heat pump provides the best attributes of the geothermal and air-based heat pumps in one machine. A dual-source heat pump is very efficient, but a straight geothermal heat pump has a higher efficiency rating than a dual-sourced system. A dual-source system has a much lower installation cost and purchase price.
The higher price may seem like a disadvantage at first, but the cost savings in operating a geothermal heat pump are returned to you within 5 to 10 years after the purchase of the system. Given that heat pumps usually last around 25 years for all parts and some parts last around 50 years, over the life of the system this results in a significant savings.