Generally, all of the heat pumps are attached to the same earth connection by a loop of pipe inside the building. Closed loop systems circulate water or an environmentally safe antifreeze through plastic pipes buried beneath Earth's surface. The fluid absorbs heat from the ground during the winter and transfers it to the heat pumps inside the building. In the summer, the process is reversed with heat from the building returning to the ground. Open loop systems operate on the same principle, and can be installed where an adequate supply of water is available.
Operating costs are substantially lower.
Kentucky Utilities commissioned studies by three engineering firms who modeled the life cycle costs of alternatives including GeoExchange. Even assuming that the GeoExchange system would cost more to install, the enormous operating and maintenance savings yielded 12 to 19 percent life cycle savings over 20 years. The study also compares energy costs for 24 schools with various HVAC designs. The three lowest operating cost schools have GeoExchange. Maintenance savings are remarkable.