AC & Heat Pumps, while essentially identical in cooling mode, heating mode is a completely different story. Air conditioners do not provide heating, but heat pumps do. Thanks to a reversing valve in the outdoor unit, a heat pump can absorb heat energy from outside air, even in extremely cold temperatures, and transfer the heat inside the home, where it releases the heat into the air. A heat pump can heat and cool, but an air conditioner cannot, which is the primary difference between the two HVAC systems. An air conditioner is typically paired with a furnace to provide heat during the cold months. Together, an air conditioner and furnace are a complete heating and cooling system.
Although a heat pump can heat a home, when outside temperatures drop below freezing, the efficiency of a heat pump is affected as the unit requires more energy to maintain warm temperatures inside the home. Typical heat pump systems have an auxiliary electric heater added to the indoor unit to add supplemental heat when outdoor temperatures drop. However because electric auxiliary heating Is not very efficient, the addition of a furnace can be a solution to this problem, creating a system that relies on the heat pump as the primary heat source but automatically switches to the furnace when appropriate.