Which type of heat pump does not require a defrost cycle?

Geothermal heat pumps—also known as ground-source or water-source heat pumps—do not require a defrost cycle. Unlike traditional air-source heat pumps that extract heat from freezing outdoor air, geothermal systems draw thermal energy from the earth or a body of water, where subterranean temperatures remain remarkably stable and warm year-round, typically staying between 45 and 70 degrees Fahrenheit regardless of surface weather conditions. Because the heat source never drops below freezing, geothermal coils never accumulate frost or ice, completely eliminating the need for defrost control boards, reversing valve defrost logic, or backup electric resistance heating strips during winter. You can verify this advantage by reviewing geothermal system specifications, which confirm frost-free operation in all climates.