A geothermal heat pump is a device that transfers heat from the ground to your house and vice versa (depending on the season). It does this through long loops of underground pipes filled with liquid or an antifreeze solution. The loops are connected to a geothermal heat pump inside the house, which becomes the furnace and the air conditioner.
It is based in the principle that the temperature below the ground is relatively constant at about 50 degrees Farenheit. This is possib/e due to the internal heat of the Earth.
Installing a geothermal heat pump for a 2000 sq. feet house costs between 10 and 20 thousand US$. In order to break even with the investment, the savings in energy consumption equal the investment in 4-15 years. This has to do with the local cost of energy and the expense of the contractor's work.
For further information, take a look at this article
