Geothermal home heating is a non-combustion heating system that transfers heat from one place (
the ground) to another (
your home).
Heat pumps (air source) and geoexchange (ground source) heating and cooling systems are non-combustion systems unlike furnaces and boilers that use fossil fuels such as diesel, oil, natural gas, LPG (Liquefied Petroleum Gas), propane and wood etc.
Geothermal systems transfers the heat that is stored in the ground to be used in your home for space heating and cooling, and domestic hot water.
Nearly all heat transfer systems can be reversed thereby providing heating and cooling. Most geothermal heating systems like ground source heat pumps and water source heat pumps, and some air source heat pumps can provide domestic hot water at a lower price.
With geothermal heating systems much less electricity is is used to move heat as opposed to creating it, this makes heat pumps more economical than electric resistance heating systems.
Geothermal systems sometimes called geoexchange systems or ground source heat pumps transfers heat from the ground (earth) and not from the air. The temperature in the ground remains relatively constant throughout the year providing heat to the geothermal system.
Additionally, geothermal heating systems are more economical than air source heat pumps that may require resistance heating (a defrost cycle for the external heat exchanger)
See how the heat exchange process works.
More on the different types of heat-pumps below: