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Should you ever run your air conditioner during the winter? If you answered “no,” you’re right. Well, mostly right. Believe it or not, there are a few situations in which your unit can be run during the winter. Here’s a breakdown of when you should and shouldn’t run your AC unit when temperatures plunge.

You Have a Heat Pump

Do you notice your AC running when you turn on the heat? You’ve double-checked that you’ve set your thermostat to “heat” and that your vents are releasing warm air. So why is this happening?

During cold weather, your air conditioner is running because it’s a heat pump.

A heat pump does double duty for heating and cooling. It moves heat instead of generating it. In summer, its refrigerant coils absorb indoor heat and move it outdoors. In the winter, its refrigerant flow reverses, absorbing outdoor heat and moving it indoors.

In this instance, it makes sense to run your AC unit all year.

Run It for Freeze Protection

Some ACs have a freeze protection mode, also known as minimum heat or low heat. This feature is helpful in areas that experience severe winter cold. In this mode, your air conditioner runs at a low setting and continuously circulates warm air, preventing it from freezing.

Freeze protection is also helpful if you have rooms or a vacation home that you rarely use during the winter. It maintains warm air that prevents pipes from freezing and rupturing when you’re not there.

Freeze protection has minimal energy consumption, making it a cost-effective feature for an air conditioner.

Run It in the Winter to Dehumidify

Air conditioners and dehumidifiers work on the same principle: they pull moisture from the air, which reduces a room’s humidity. During cold weather, you may notice humidity steaming up your windows, Running your air conditioner will de-fog your windows and dehumidify your home’s air.

Run It to Remove Stagnant Air

If you want to freshen your indoor air, open your air conditioner’s vent and set the unit to “Fan Only.” This vent is an opening between the outdoors and indoors. When it’s open, it circulates fresh outdoor air throughout the room and dispels stale air.

However, there are several drawbacks to running your air conditioner in cold weather.

Overheating the Compressor

Air conditioners can’t tolerate temperatures below 60 degrees Fahrenheit. In extreme cold, the AC’s compressor can get overworked as it struggles to function. At best, it will need significant repairs; at worst it may completely fail.

This also applies to overuse: the compressor may overheat if it’s run outside the lower temperature limit for a significant amount of time.

Poor Lubrication

Lubricants help the compressor smoothly run. Lubricants aren’t one-size-fits-all. Air conditioners specifically use heavier grade oil. In the winter, lubricant oil can become too thick to circulate properly, damaging the compressor or causing it to completely seize up.

On the other hand, if the temperature is at least 60 degrees Fahrenheit, it’s a good idea to run the AC unit occasionally. Be sure to do so after the temperature has been 60 degrees for at least three days. This will circulate the oil to prevent a dry start when the weather gets warmer.

Overriding the Ambient Sensor

Modern air conditioners have a sensor that prevents them from turning on in low temperatures. If you try to override this feature and turn the air conditioner on, the unit may fail. If you have an older unit lacking these sensors, it may attempt to run in cold weather and become damaged or break down completely.

Damage to the Condenser Coil

Running an air conditioner in cold temperatures could be risky. If condensation builds up on the condenser coil and turns to ice, it could freeze the AC unit, possibly causing irreparable damage.


Running your AC unit in cold weather could cause it to flood. The air conditioner’s compressor circulates vaporized refrigerant while it transports heat from the inside of your home to the outside. However, in the winter, there isn’t enough heat to vaporize the refrigerant, so it remains a liquid, backwashes into the compressor and floods it.

This can cause gradual or sudden, severe damage.

What About Window Air Conditioners?

Not only should you avoid using your window AC in the winter, but you should remove it completely. A window air conditioner is unprotected and can fall prey to issues such as freezing coils. Unless it’s exceptionally well-insulated within your window, it’s also going to create a cold spot in your home.

Contact Us

At Progressive Air Systems, we believe that the cons of running your AC unit in the winter outweigh the pros. However, if you need to have your air conditioner promptly and professionally serviced during cold weather, or any time of the year, please call us.