In regions without any high temperature geothermal resources, a ground-source heat pump (GSHP) can provide space heating and space cooling. Like a refrigerator or air conditioner, these systems use a heat pump to force the transfer of heat from the ground to the building. Heat can be extracted from any source, no matter how cold, but a warmer source allows higher efficiency. A ground-source heat pump uses the shallow ground or ground water (typically starting at ) as a source of heat, thus taking advantage of its seasonally moderate temperatures.Goswami, Yogi D., Kreith, Frank, Johnson, Katherine (2008), p. 9-4. In contrast, an air source heat pump draws heat from the air (colder outside air) and thus requires more energy.
