Why Is My Thermostat Staying On Auxiliary?

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Why Is My Thermostat Staying On Auxiliary?

More and more homeowners are discovering that heat pumps are a good choice for home heating even in cold winter locations like Steger, IL and Crown Point, IN. This also means those homeowners are also learning more about the auxiliary heat setting on their thermostat and why it’s a bad thing when a heat pump system seems to stay on auxiliary heat.


If you own a heat pump you already know it works by squeezing existing heat from the outside air and transferring it into your house. Even when the outside air feels cold there is still heat that can be removed from the air but when it gets cold a heat pump will be less effective. That’s where the auxiliary heat comes in.


In simple terms the auxiliary heat comes from a type of space heater (electrical resistance heating) that is part of the air handler. The heated air is circulated through the home. There are two basic reasons why auxiliary heat will kick in:

  1. When the outside air temperature drops below freezing. As indicated earlier, this is when heat pumps are less efficient and an extra boost is needed to keep your Steger, IL or Crown Point, IN home warm and comfortable. The auxiliary heat will turn off when the temperature rises.
  2. By their nature heat pumps warm the house very gradually. As a result, if you turn the thermostat up by a significant amount, usually three degrees or more, the auxiliary heat turns on to speed up the process. Once the desired temperature is reached the auxiliary heat turns off.


The drawback is the auxiliary heat isn’t very energy efficient, so you want to use it as little as possible. If you see the auxiliary heat is staying on you need to call Merts Heating & Cooling to fix the problem quickly or you are going to see a large electric bill. The problem could be with the thermostat or just a sign your heat pump needs maintenance by a qualified HVAC technician. Call Merts Heating & Air Conditioning now to schedule seasonal heat pump maintenance to make sure your auxiliary heat is doing its job but not wasting money. Be sure to like us on Facebook and follow us on Twitter to learn more about the services Merts offers.