geothermal heating
Heating is generated by transferring natural heat underneath the building or nearby into the interior.
Geothermal heating is the practice of extracting natural heat from the earth for direct transfer to indoor areas. The process is highly favored as a sustainable source of energy, because it does not burn carbon fuels or require transfers of energy across large distances. However it is not equally available in all areas, and is a much more plentiful source of heat in areas with volcanic or other tectonic activity.
Natural heat from the earth is the source for indoor heating. The definition concerns that thermal supply rather than electricity generated elsewhere from geothermal resources.
A heat pump can participate in supplying geothermal heat. The existing heating types nevertheless identify the geothermal source separately.