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Do Air Conditioners Work When It’s Cold Outside?

When it’s cold outside, running the heat for long periods of time can sometimes make the air inside stuffy or stale. It might seem like a good idea to blast the air conditioning for twenty minutes or refresh a room or home, but standard air conditioners are not designed to run in cold weather.

Air conditioners work when it’s cold outside. However, if the outdoor temperature is less than 60 degrees Fahrenheit, the portion of the air conditioner unit positioned outside of the building could malfunction while working, compromising the entire cooling system.

This article will give a simple explanation of how air conditioners work and why you shouldn’t run yours in cold weather. I will briefly discuss exceptions to this rule and introduce you to alternatives to keeping the air in your home fresh during winter.

Why You Should Not Use Your Air Conditioner When It’s Cold Outside

A standard air conditioner uses outdoor equipment that can not operate efficiently when colder than 60 degrees Fahrenheit. An air conditioner uses an outdoor compressor to heat a liquid called a refrigerant and send it through a series of small pipes and coils. Cold weather makes it harder for the compressor to maintain the high temperature needed to function.

The coils used to cool the refrigerant can freeze in winter. The refrigerant must run through these coils to release the heat it’s carrying from the house. If the coils are frozen, it’s impossible for the compressor to push the refrigerant through.

Industrial strength lubricant can also be rendered useless in frigid outdoor air. In order to function at optimum levels, the outdoor equipment of the air conditioner needs this lubricant to run smoothly. Cold air outside can make this substance too hard for the air conditioning unit to perform safely.

Air conditioners run most efficiently when prompted to make small temperature changes. A hot and stuffy house may force the air conditioner’s compressor into overdrive too quickly after a period of inactivity. It will also have to run for a long enough time to exchange all the heated air in the house to the much lower temperature suddenly set at the thermostat.

How a Standard Air Conditioner Works

When air is forced through a cold object, the air cools down. This is the most basic way to understand how the air in your home gets and stays cool. Though there are many moving parts in a cooling system, the concept is quite simple. Let’s take a closer look at the portion of the air conditioner that is directly affected by cold weather.

A condenser unit is a large, cube-shaped metal encasement. It rests just to the side, behind or, in some cases, on top of your house. Inside the condenser unit are three pieces of equipment that are crucial to dispersing the heat that comes from inside your house during the hot months.

What’s inside a condenser unit?

  • fan
  • compressor
  • condenser coil

The process step-by-step that occurs inside the condenser unit:

  1. The refrigerant flows like gas through the compressor, which repressurizes the heated substance.
  2. The refrigerant is then sent as a liquid into the condenser coils at a high temperature.
  3. A fan blows outside air over the coils to help cool the refrigerant, dispersing the heat. 
  4. At a lower temperature and high pressure, the refrigerant runs from the condenser coils back into the house through the coolant lines.

So How Does an Air Conditioner Work Inside the House?

  • The refrigerant flows from the outside compressor to the inside thermal expansion valve. This valve is controlled by the thermostat. As the refrigerant goes through the valve, it lowers the pressure so that the refrigerant can easily absorb heat again.
  • Then the refrigerant runs through evaporator coils, which become very cold. Air from the house is blown across the evaporator coils by the blower and cools down. At the same time, the refrigerant soaks up the heat from the air and then changes back into gas form. The cool air continues to recirculate through the house.
  • Finally, the refrigerant takes all the heat, flows back outside to the hard-working compressor, and begins the cycle again. The compressor runs most efficiently at a steady level when your thermostat fluctuates only within a range of 7 and 10 degrees. You get the most energy savings the steadier you keep your thermostat.
  • The strain on the compressor happens when it works outside of your usual temperature range. The length of time doesn’t necessarily cause the compressor to break; this causes energy savings loss. If you turn on the air conditioning and set it at 70 degrees Fahrenheit, but it’s 100 degrees outside, this is what could overtax the compressor.
  • You can purchase a smart thermometer to maximize your energy savings when cooling your home. Consider the Emerson Sensi Tough WiFi Smart Thermostat. Installation is quick; it’s compatible with most residential air conditioning systems and smart home programs, including Google Assistant and Alexa. It also has an app for instant manual override off-site at any time.
Emerson Sensi Touch Wi-Fi Smart Thermostat with Touchscreen Color Display, Works with Alexa, Energy Star Certified, C-wire Required, ST75

When CAN an Air Conditioner Work When It’s Cold?

If the lowest temperature goes no lower than 60 degrees, you can keep your air conditioner running safely. This helps in two ways: it keeps energy costs down while also relieving strain on the system when the weather begins to warm up for the season.

Some air conditioning units are designed to operate year-round. These units run on an integrated heating system. This kind of system for the home acts with a dual purpose. It cools the air and heats the water. Instead of having the refrigerant take the heat out of your home to dissipate through the condenser coils, the home’s heat is used to provide you with hot water.

How Do You Keep Indoor Air Fresh When It’s Cold Outside Without Turning On the Air Conditioner?

Open the windows! This seems rather obvious, but there is an initial version most of us have to open the windows in the middle of winter. To achieve a refreshed room as quickly as possible, create cross-ventilation by opening two or three windows. Air will circulate faster, especially if the windows are across the room from each other. In my experience, only 10 minutes is needed to exchange outdoor and indoor air for a standard-size living room.

Run a fan. Again, there’s a natural rejection of creating wind in wintertime. However, this method is also an effective way to make a breeze and recirculate the stale air in a room. Depending on the size of the room, just a few minutes does the trick. For faster results, place a bowl of ice in front of the fan. After all, hot flashes happen year-round.

Final Thoughts

Your standard home air conditioner can work when it’s cold, but it puts too much strain on the compressor unit.

There are two ways you can break this rule. First, the outside temperature doesn’t go below 60 degrees. Second, your home runs on an integrated heating system in which hot air is used to heat water instead of the refrigerant shedding the heat outside as wasted energy.

Use simple methods to refresh the air in a room. Cross-vent with open windows or a fan to circulate that closed in, stuffy feeling. Stay fresh and cozy in cold weather while giving your air conditioner a rest!


  • Vincent Steele

    Vincent is a freelance writer based in Santa Ana, California. When he isn't writing articles for Temperature Master, he can be found biking or hanging out with his cat, Shelly.

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