Most residential heat pumps in the U.S., including ductless minisplits and ducted minisplits, are air-source heat pumps. During the summer, this type of heat pump acts like an air conditioner: it collects heat from indoor air and transfers the heat to the outdoor air. During the winter, the heat pump reverses direction: it collects heat from the outdoor air and transfers the heat to the indoor air.
A second type of heat pump is the ground-source heat pump (GSHP). During the summer, this type of heat pump transfers heat from indoor air to the soil around your house. In some cases, it may transfer heat from indoor air to the water in a drilled will, or to a nearby lake or pond. During the winter, a GSHP collects heat from the soil around your house (or from the water in a drilled well or nearby pond) and transfers the heat to indoor air.
To effect this heat transfer, a ground-source heat pump system requires either buried tubing—vertical loops of tubing inserted into boreholes, or horizontal lengths of tubing buried in deep trenches—or the circulation of water from a drilled well or pond through tubing that conveys the water to the heat pump.
Some manufacturers of ground-source heat pumps state that their equipment gathers renewable energy, or label their equipment as “geothermal.” To clear up these misconceptions: a ground-source heat pump does not use geothermal energy. It isn’t a type of renewable energy system. Like an air-source heat pump, it’s simply a type of heating and cooling system that uses electricity as its fuel.
Air-source heat pumps are much cheaper and almost as efficient
GBA has dozens of articles on ground-source heat pumps (many of which are listed in the “Related Articles” sidebar). If you are…
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