Geothermal heating and cooling systems, also referred to as "ground source", "ground-coupled", or "earth energy" heat pump systems, are "...self-contained, electrically-powered systems that take advantage of the Earth's relatively constant, moderate ground temperature to provide heating, cooling, and domestic hot water more efficiently and less expensively than would be possible through other conventional heating and cooling technologies" according to IGSHPA, the International Ground Source Heat Pump Association.