Why Does My AC Compressor Turn On and Off Repeatedly?

Updated: | Author: Brad Javernick | Affiliate links may be present.

If you notice that your AC compressor is turning on and off more often than usual, the frequent sounds can be a real disturbance. In addition, this means that your AC is also working less efficiently than it should be.

It’s important to find the root of the problem so that you can save time, electricity, and increase the lifespan of your AC system.

If your AC is switching on and off more than 2-3 times per hour, this is likely an indication of a problem. The issue could be easy to fix by yourself such as dirty vents or condenser coils. Other issues could be that your AC is too big, the refrigerant is low, or the thermostat is malfunctioning or incorrectly placed.

Is It Normal for an AC Compressor to Kick On and Off?

It is completely normal for AC to kick on and off throughout the day in cycles. The AC should run until your home reaches the desired temperature and then kick back off again.

When your AC is working properly and the temperatures are relatively mild, it is normal for these cycles to last about 15-20 minutes. This means your AC should turn on and off about 2 or 3 times per hour. If you notice this happening, your AC compressor and thermostat are most likely functioning completely fine.

If the temperatures are very hot, like in the middle of summer, the cycles will likely be a bit longer. On especially hot days it is normal for your AC to run continuously and rarely switch off.

In general, the only time you should be concerned about your AC cycles is if they are very short. If your AC compressor is turning on and off very quickly, this is a sign that there is a problem.

Why Does My AC Turn On and Off Quickly?

If you notice that your AC is turning on and off very quickly, known as short cycling, this means that something is not working properly. There are quite a few potential causes that could be easy to fix or could require professional maintenance.

It is important to figure out the root of the problem and fix it to make sure that your AC is working efficiently. When it kicks on and off quickly this uses more electricity and can cost you more while also cooling your home unevenly.

Dirty Air Vents

One potential cause for short cycling is dirty air vents. If your air vents are too dirty, this leads to restricted air flow through the AC. In extreme cases, this can cause frozen coils which leads to short-cycling.

If this is the case with your AC unit, it is very easy to fix. Simply make sure that the air vents are cleaned and that air can flow properly.

Dirty Condenser Coils

When the condenser coils on the outdoor component of your AC unit have become too dirty, this can also lead to short cycling. This is more likely to happen if it has been a while since the last time that you had the unit serviced.

In the event of dirty condenser coils, first, remove any debris from the outdoor unit with a stiff brush or rag. This should be enough in most cases, but if you would like to be more thorough, you can also wash it down with soap and warm water.

Your AC Might Be Too Big for Your Home

If your AC unit is too large for the space it is cooling, this can also be the cause of short cycling. When an AC that is too large kicks on, it will cool the space very quickly and then shut off again. One sign that this could be your problem is hot and cool spots in your home.

Although it might sound like a good thing that your AC can cool down your home quicker, this is actually less efficient. Talk to a professional about replacing it with an AC that is appropriate for the size of your home.

Low Refrigerant

Another potential cause for short-cycling is when the refrigerant fluid in your AC is running low. Normally the refrigerant is just cycled through the system and should not decrease. This means if you are running low on refrigerant, there must be a leak.

If this is the case, it is best to call in a professional. They will be able to find and fix the leak as well as refill the refrigerant. Then your AC will be back to functioning normally.

Thermostat Problems

If your thermostat is low on batteries or malfunctioning in any way, this can lead to many issues including short-cycling. The thermostat is what tells the AC to turn on and off, so any problems with it can lead to an irregularly functioning AC.

Even if your thermostat is functioning perfectly, it can still cause short cycling if it is not in an optimal location. For example, if your thermostat is right next to a vent the temperature sensors will detect a lower temperature more quickly causing the AC to switch off before the space is cooled evenly.

If this could be your problem, try moving your thermostat away from any vents, fans, and windows. This will allow it to get a more accurate temperature read for the room.

Final Thoughts

When your AC is switching on and off too frequently, this is almost always due to a problem with the unit and should be fixed as soon as possible to save you electricity and money.

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About Brad Javernick

Brad is a licensed home inspector and the editor of Home Oomph. He's a massive DIYer, and loves to take on new home renovation projects!

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