A:Put simply, a heat pump is an air conditioner that can go in reverse. When you run an a/c system, the indoor coil absorbs the heat from the house as the air passes through the coil. The heat is then released outside. A heat pump absorbs the heat from the outside air and releases it indoors during the heating season. Old-timers in the hvac business often used to call heat pumps "reverse-cycle A/C units.
