In the North Georgia area, all heat pumps require some sort of auxiliary heat – also known as backup heat or emergency heat – due to our winter temperatures dipping below 42 degrees. Heat pumps are not as effective at producing heat when the temperature drops into the freezing range so auxiliary heat is installed to assist the heat pump in heating the home. Under normal operating conditions, the auxiliary heat is brought on automatically by the thermostat when the indoor temperature drops during heat pump operation. Electric heat kits are the most common form of back up heat in the North Georgia area. A higher end option is a dual fuel system which consists of a furnace as backup heat the electric Heat Pump.
Also, there are also times during cold, wet weather when the outdoor coil may ice up and your heat pump must go into a defrost cycle. This is nothing more than reversing the process back to cooling mode. Cooling mode makes the outdoor coil hot and melts any ice. The defrost cycle should only last a few minutes and then return to heating mode. During the defrost cycle, your comfort system is in cooling mode and the supply air is cool. To offset this cool air, the auxiliary heat clicks on to help heat the home. A mist or fog may be visible from the outdoor unit during defrost.