Thermostat: Auxiliary vs. Emergency Heat Settings

Feb 16, 2022 | HVAC

Heat pumps generate heat by extracting latent heat from outdoor air, concentrating it and then circulating it through the ducts in your home. Down to a particular temperature, there’s enough latent heat in cold air to warm your indoor spaces. However, if the temperature drops further, your heat pump won’t be able to extract enough heat to meet your needs. At this point, your heat pump will need to use either auxiliary or emergency heat to keep your home warm.

Thermostat: Auxiliary vs. Emergency Heat Settings

In this post, HVAC and refrigeration maintenance expert A/C and Refrigeration discusses the difference between auxiliary and emergency heat.

Auxiliary Heat

Auxiliary heat is a setting on your thermostat that automatically activates when outside temperatures drop to 30-40 degrees. This thermostat setting involves the use of heat strips, which are found in indoor units and act as the heat pump’s secondary source of heat.

When these heat strips kick in, your heat pump will still continue drawing in as much heat as it can while the heat strips provide the rest of the required heat. This has no known effect on your indoor air quality. However, you can expect a slight increase in your energy bill when this backup heat source is utilized.

Emergency Heat

Emergency heat is very similar to auxiliary heat, except that this setting has to be manually selected and switched on at the thermostat. Experts recommend using the emergency heat setting only when the outdoor unit can’t pull any heat at all. Typically, this happens as a result of a broken part or system failure.

When the emergency heat is turned on, the heat strips will activate and provide 100% of the heat needed to warm your house. This can cause a significant increase in your electric bill, especially if you use this setting for a long period of time. It’s also to be expected that the heat strips alone won’t be able to warm your house to the desired temperature. However, they will generate enough heat to keep your home from freezing. 

A/C and Refrigeration offers their expertise in heating and cooling systems, commercial refrigeration, indoor air quality and more. We ensure the best solutions for our clients so that they can maximize indoor comfort and energy savings. To request a free quote, call us at (602) 488-7161 or fill out our contact form.