A home heated with a cold climate heat pump will be very comfortable year-round. Achieving home comfort efficiently is different however, than with a conventional furnace. Conventional furnaces can heat the air to higher temperatures than a heat pump and as a consequence, the air coming out of an air register will not feel as warm with a heat pump. A conventional system will also be able to raise the temperature faster when setbacks are used. A home heated with a heat pump will use energy more efficiently when the thermostat is set at a constant temperature and setbacks at night or during unoccupied periods are minimized. This has the added benefit of more even heat distribution which can feel more comfortable.
On cold and damp days, frost can build up on the outside unit of a heat pump, reducing its ability to absorb heat from the outside air. When this occurs, most heat pumps will briefly run in reverse, drawing heat from the home to defrost the outside unit. Backup resistance heat may be used during this time to minimize the effect on the home’s indoor air temperatures. Defrost cycles are generally triggered by sensors that detect the effect of frost buildup or by a timer: the first system is more energy efficient.