In Florida, you have three types of heating sources with your HVAC system: For this discussion, we will focus on the difference between a traditional heater/furnace and a heat pump system. Many Floridians who lived up North do not understand the difference between auxiliary heat and emergency heat.

For more information on our heating services, call Scott’s One Hour Air Conditioning & Heating at (813) 548-5028 or contact us online.


What Are Auxiliary Heat & Emergency Heat?

  • Auxiliary Heat – This is the secondary heat source that turns on automatically.
  • Emergency Heat – This is when you turn on the secondary heat source.

The difference between auxiliary heat and emergency heat is simply the name. Both forms of heat are the exact same heat elements but are labeled differently.

Auxiliary Heat

Here in Florida, we typically use the heat pump for our primary source of heat when heating the home; however, this unit also has a limit. A heat pump can satisfy your home’s heating needs as long as the outdoor temperature remains at or above 45 degrees. At temperatures around 45 degrees, the outside coil can and will freeze up, which will cause the system to go into defrost mode. While in defrost mode, the outdoor unit will signal the air handler to turn on the auxiliary heater. This heater is an electric heater similar to a toaster oven and will supply supplemental heat to the home while the outdoor unit is defrosting itself. Once the outdoor system is defrosted, the auxiliary heater turns off and the system continues in heat pump mode.

Emergency Heat

Emergency heat is a term we use for when the homeowner must force the system into the electric heating mode if their heat pump system has failed or is not working correctly. This heater is the exact same heater as the auxiliary element, only used in a different format. The heater is typically not designed to heat your home to 80 degrees, but only as a supplement heat source while the heat pump is in defrost mode or as an emergency backup in the event of a system failure.

Auxiliary Heat’s Functions

  1. The first function is to back up the heat pump if the thermostat has a difference of 3 degrees or more from the set temperature to the actual temperature inside the home. If this happens, the heat pump and heat strips will run together to create warmer air to more efficiently heat the home. Once the thermostat set point is within 2 degrees of the temperature inside the home, the auxiliary heat will turn off.
  2. The second function is when the outdoor system goes into defrost mode, as stated above.

When we come out to do our 77-point checklist on your system, we’ll actually kick it into defrost mode to make sure it’s working. We basically freeze the system up and make the equipment work a little harder to make sure you’ll have heat when you need it.

If you haven’t had that check done in a while, give Scott’s One Hour Air Conditioning & Heating a call at (813) 548-5028.