A heat pump works by pulling in heat from its environment. They need electrical power to work, but it can supply more heat than the electricity used.
Residential homes use two primary heat pumps for space heating and cooling: – Ground-source (or geothermal) – Air-source
Ground-source heat pumps can extract heat from the earth, well water, or a pond when used to heat a home using forced air or hydronic systems.
Air-source heat pumps are like window air conditioners running backward. Because they are compact, affordable, and can offer cooling, air-source heat pumps are an excellent choice for tightly constructed and well-insulated homes.
Most air-source heat pumps work well in milder climates where heating and cooling are required, but winters are not harsh. But in mild climates, they can save you money...
Changing from electric resistance heat to an air-source heat pump can save energy expenses by up to 40%, according to the U.S. Department of Energy.
Absorption heat pumps, which are an adaptation of the air-source heat pump, are powered by heat sources other than electricity. Both heating and cooling are accomplished using an ammonia-water absorption cycle.