Heat pumps are characterised by two loops, the source or the external loop and the sink or internal loop. The heat pump collects the heat stored in the Earth (source) via the external loop and delivers it to the inside loop (sink) for use in the heating system. The Earth below the frost line remains at a relatively constant temperature year round. This temperature equates roughly to 7°C TO 9°C. Because this temperature remains constant GSHP's perform with greater efficiency and in a far larger range of extreme temperatures than other types of heat pumps.
GSHP's are able to transfer heat from the ground with minimum use of electricity. When comparing a GSHP with a conventional system savings of between 40% and 70% can be achieved in annual heating costs. Even with high initial cost of the GSHP the payback period is relatively short, typically between five to seven years. Geothermal Heat Pumps are environmentally friendly, they are a renewable energy source, non-polluting and recognised as one of the most efficient heating systems available.