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How Often Should a Car AC Compressor Cycle On and Off?

AC in a luxury passenger car

When your car makes an unusual, it’s a cause for alarm. One noise you may notice frequently is the sound of your air conditioner’s compressor cycling on and off. If you’re not hearing this noise often enough or too frequently, it may cause you to worry.

The automobile expert, Rony Jacobs, of My Vehicle Talk stated, “Your standard AC compressor would cycle for about 15-20 minutes before going off. Or it’s 2-3 times in an hour.” 

What’s a Compressor?

Metal AC compressor

First and foremost, you should understand what the compressor of your AC is. According to Pete Caldwell of, “You can call it the heart of the air conditioning system.” It works by compressing the refrigerant and turning it into liquid.

The compressor then moves the condensed refrigerant through a pipe into the evaporator. It’s the part of the AC unit that’s mainly responsible for your AC blowing cold air. 

What Does It Mean When the Compressor Is Cycling?

You’ll notice that your air conditioner will make a noise, which is the air compressor turning on. It tends to run for about 15 to 20 minutes each time it turns on. As it’s turning on and turning off, it’s cycling. 

This process is what keeps the temperature in your automobile’s cabin comfortable. 

What Factors Affect AC Cycling?

The aforementioned figure of the average number of cycles is merely an estimate. The compressor may cycle less or more than that depending on the setting you have your AC set to. For instance, if you have it on a lower setting, the compressor won’t cycle as much.

On the other hand, on a higher setting, it may cycle more frequently. The temperature of the air outside your vehicle can also affect how the AC’s cycling. For example, if it’s hotter than usual outside, your condenser is going to work harder to keep the air in your vehicle cool.

You’ll notice if the temperature outside increases, your compressor will start to cycle more. 

When Should You Worry About the Cycling of Compressor?

Ventilation holes in a luxury passenger car

Your AC’s compressor will cycle on and off at times. Typically, it’s not a cause for concern, even if you occasionally notice that it’s cycling more often or less often than normal. That could stem from external factors rather than an issue with the compressor. 

Short Cycling

With that being said, there still are times you should be concerned about the compressor. For instance, short cycling occurs when the compressor isn’t completing a full cycle. When this occurs, your cabin won’t cool off as well or as quickly.

Not to mention, short cycling puts more pressure on your AC unit than necessary. It can also impact the AC’s internal mechanisms. Short cycling could arise if you have a faulty thermostat — the device responsible for sensing the temperature of your cabin.

When changes occur, the thermostat sends signals to the AC unit. If your thermostat is malfunctioning, it could be transmitting the wrong signals to the air conditioner. As a result, your compressor may cycle on and off irregularly. 

Low refrigerant levels will trigger the compressor to work more frequently than usual. When the refrigerant level is low for too long, it causes your compressor to malfunction and short cycle. This tends to stem from a refrigerant leak. 

Your evaporator coils may freeze from using your AC in the winter or a mechanical problem. Your AC will then short cycle. Fortunately, this is easily correctable when you allow your system to thaw.

Sometimes, a dirty air filter will cause your compressor to short cycle. A clogged or even dirtier-than-normal AC system prevents the air from flowing throughout your system freely. Your compressor may then turn on and off regularly.

Fortunately, your system will stop cycling like that when the air filters are cleaned. Certain electrical issues can also contribute to a compressor short cycling. This is a problem best left to a professional to repair. 

Air Compressor Running All the Time

AC in a luxury car

Typically, a fully functioning air compressor doesn’t run all the time. Instead, the compressor cycles on and off. If it is running all the time, it could lead to your AC failing sooner than anticipated. 

Low refrigerant may contribute to your compressor running all the time. That’s because it has to work harder to continue running normally. Newer cars have a feature known as auto climate control, and it’s responsible for automatically controlling your cabin’s temperature.

In some cases, this causes your air compressor to work harder to keep your cabin cool. As a result, your compressor may run all the time. If you have a clogged or overly dirty air filter, it will cause your compressor to continuously run in an attempt to cool down the air in your vehicle. 

Your AC compressor may cycle on and off more or less frequently than usual at times. However, when you notice that it’s short cycling for extended periods or is running continuously, it’s time to figure out the problem to prevent the AC from failing prematurely. 


How Often Should A Car Ac Compressor Cycle On And Off? (