This system work by first installing piping in the ground deep enough to get below the frost line or about 2 feet or more down.  This piping is filled with fluid which circulates the consistent temperature up to a unit called a heat exchanger located within the house or building.  The heat exchanger then does one of two things.  One, it cools the building by removing the heat from the air and sending it into the ground.  Two, by heating the already consistent temperature from the ground to the few degrees needed to heat the building.

 The cost for purchasing and installing this system is considerably more than a typical HVAC system but carries some perks that typical systems do not.  Depending on the size of your house and the earth it is resting on (stone, soil or near a pond) the system can typically cost from $15,000 to $40,000.  Many systems come with as much as a 50 year guarantee.  There are frequently tax savings which reduces the time involved in recouping the costs.  Furthermore, beyond the long term savings of a geothermal heat pump, is the short and long term benefits of global energy conservation. 

   Many federal and state incentives are being given to those who install the a geothermal heat pump system, to read more see http://www.geoexchange.org/