Banner image with various Parks technicians Banner image with various Parks technicians


What’s the Difference Between Emergency Heat & Auxiliary Heat?

Closeup Shot Of Home Furnace Burner Ignited

Having reliable heat in the winter is critical for every Charlotte-area homeowner, and ensuring your thermostat is set properly can help you achieve a warm indoor environment. Most modern thermostats offer various heating options, including auxiliary and emergency heat settings. But what’s the difference between emergency heat and auxiliary (aux) heat, and when should each be used?

In this blog post, our HVAC experts at Parks Heating Cooling Plumbing & Electrical will cover the differences between auxiliary heat and emergency heat on your thermostat, helping you understand how your thermostat operates and how it can help ensure optimal comfort on the coldest days of the year.

What Is Emergency Heat on a Thermostat?

Emergency heat is a setting on your thermostat that’s typically used in conjunction with a backup heating system. For instance, if you have a heat pump in your home with a gas furnace as a backup, the emergency heating system will engage your furnace on the coldest days of the year.

Unlike the aux heat setting, emergency heat must be engaged manually and should only be used in temperatures that are below freezing (32 degrees F and below). Emergency heat should be used sparingly, as it’s less energy-efficient and can result in higher utility bills when used repeatedly.

What Is Auxiliary Heat on a Thermostat?

Auxiliary heat (also referred to as “Aux Heat” or “Heat Pump Aux”) is the preferred setting for your heat pump. A heat pump boasts incredible energy efficiency; however, these innovative systems can sometimes struggle to maintain the desired indoor temperature during periods of extreme cold. Auxiliary heat kicks in when the heat pump alone cannot provide sufficient warmth to satisfy the set temperature on your thermostat.

How Does Aux Heat Work?

Unlike emergency heat, aux heat engages automatically when the thermostat detects that the heat pump is struggling to satisfy your comfort demands due to extreme cold. When this happens, the auxiliary heat setting will activate the supplemental heat system automatically, providing quick and efficient heating to bring your home up to the desired temperature.

When Will Aux Heat Kick On?

The exact temperature at which your aux heating setting kicks on depends on the programming of your thermostat. Usually, the auxiliary heat setting will engage automatically when the disparity between your set temperature and the actual indoor temperature becomes significant. For instance, if your thermostat is set to 68 degrees but the indoor temperature drops to 65 degrees, the thermostat may automatically activate the supplemental heating system to bring your temperature back to the desired level.

By contrast, emergency heat must be activated manually and should only be used in extraordinary circumstances when the heat pump is not functioning properly or when the outdoor temperature is 30 degrees or below.

Get Help With Your Thermostat From Parks!

If you’re having trouble with the way your thermostat interacts with your dual-fuel heating system, Parks Heating Cooling Plumbing & Electrical is here to help. Our NATE-certified technicians have the skills and tools necessary to address any issues with your thermostat, heat pump, or supplemental heating system, offering same-day services with no overtime charges for your convenience.

Schedule thermostat or heat pump repairs in the Charlotte area by calling 704-596-8200 today!  

Contact Us

Contact Us Today

Parks Heating Cooling Plumbing & Electrical female technicians and van Parks Heating Cooling Plumbing & Electrical female technicians and van

Become a Parks Family Plan Partner Today!

Sign Up for the Parks Family Plan & Receive Guaranteed Service Day or Night.
  • Biannual high-performance system checks for HVAC
  • Complimentary plumbing video inspection
  • Lowered energy usage & lower monthly bills
  • Unparalleled protection & peace of mind
  • Member-exclusive service discounts & perks
learn more