Why Your Air Conditioner Is Running When The Heat is On

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Updated May 15, 2023

If you are new to the world of indoor cooling, you may wonder why your air conditioner is running when the heat is on. Even the best air conditioners, after all, run into maintenance issues, and they could cause this specific problem. If the air conditioner is running when the heat is on, it might be because of a setting called “auto” or “heat pump” mode. This mode helps circulate warm air throughout the room. It’s normal for some HVAC systems to do this. If you’re unsure, ask a professional for help.

So, what to do when the AC runs during the winter months, and how to fix it? Keep reading to find out.


  • There are several reasons why your AC would run during the winter months while your heater is actively engaged.
  • Check the thermostat to ensure it has not accidentally been set to a low temperature, which could have been done during the summer months.
  • Take a look at your heat pump settings and evaporator coil, in addition to calling in a pro to the outdoor unit for regular maintenance.

Why Does the AC Run When the Heat is On?

If your air conditioner keeps running while turned off, particularly when the heat is on, there are many reasons as to the cause. If the air conditioner heater is not working, that could have caused some integration issues. If you recently replaced the heat pump with an air conditioner, that could cause some issues. If you are curious on what these AC types are, read our comparison of a heat pump vs AC. Another reason why this happens? When your air conditioner thermostat is not working, the system doesn’t know what to do.

Insider Tip

Regular maintenance will ensure your AC unit is in top working order and allow you to catch any developing issues early.

No matter the issue, even if your air conditioner makes a loud noise when shutting down, here are some essential troubleshooting tips to solve the problem.

Check the Thermostat

This is an obvious one but easy to miss. If you have a hybrid HVAC system that handles both heating and cooling, or even if you have an unaffiliated system, there could be some miscommunication when it comes to thermostat settings. Give that thermostat a check to ensure it is not set to, say, 65 degrees Fahrenheit. Set it to the appropriate temperature to suit your taste and give it an hour or so and see if the problem has resolved itself. If not, it might be time to consider looking into our Black and Decker Portable Air Conditioner and Heater review.

Engage Heat Pump Controls

If your air conditioner is a hybrid model outfitted with a heat pump, it is helpful to understand how this system works. The heat pump here uses the same ductwork and components as the AC unit, just in reverse. So head to your heat pump settings and disengage the air conditioning unit. You may have to reset the whole system for the changes to take. Are you not sure if you even have a heat pump? Check the manual that accompanied your HVAC system.


Dirty air filters can impede the efficacy of both your air conditioner and heater.

Call in a Professional

Call a competent professional to handle the situation when all else fails. These pros are well-trained to suss out any conflicts between your air conditioner and your heater. They can even recommend the best portable air conditioner heater combo for your space, so you get all-in-one climate control.

STAT: If your fan is switched to the “on” position, it will continuously run. You should set it to the auto position, so it only runs when the HVAC unit is running. (source)

Air Conditioner Running When Heat Is On FAQs

Is your AC acting up?

If your air conditioning system is acting up, resulting in decreased efficiency and increased utility bills, check on the various components, such as the condenser coils, air conditioner fan, and the built-in heating mode.

Why does the fan keep running on my air conditioner?

If your air conditioning fan keeps running, call in a professional technician for some much-needed AC repair.

Will running AC in cold weather damage it?

It really depends on a number of factors, but it sure will increase your energy bills. Your outdoor unit could be at risk for some repair issues, especially during the heating season.
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