Window AC Cycling On & Off? 7 Simple Fixes To Solve It

window AC cycling on and off

Is your window AC cycling on and off?

I’ve been there too! I understand how frustrating it can be when your window AC short cycles, especially during summer.

The good news is that you’ve come to the right place for answers.

If your window AC keeps cycling on and off, you’ll need to clean the air filter and coils, inspect the thermostat, and check for power issues. It’s also important to check the refrigerant levels, examine the compressor, and consider the size of the unit.

Read on to keep your window AC from cycling on and off!

Window AC Short-Cycling? Try These 7 Fixes

It’s normal for your window AC to cycle on and off, as it turns on when the room gets warmer than the set temperature and turns off once it reaches the desired level.

However, if your window AC is cycling on and off too frequently, it indicates a problem with one of the internal components.

Don’t worry, though! In this section, I’ll guide you through the seven steps you should follow to inspect your window AC and solve the short-cycling problem.

Are you ready? Let’s dive in!

#1 Clean the Filter

When fixing a window AC that keeps cycling on and off, I always start by cleaning the air filter.

The filter is responsible for trapping dust, debris, and other particles from the air to prevent them from entering the cooling system. When the filter becomes clogged, it can restrict airflow. As a result, your window AC can overheat and shut off as a precaution to prevent damage.

dirty air filter
A dirty filter can cause your window AC to cycle on and off.

To keep your window AC from short-cycling, it’s important to clean the filter every month during summer. Here’s how to do it:

  1. Unplug your window AC from its power source.
  2. Remove the front cover using a screwdriver to access the filter. Some covers can simply slide off, so please refer to the owner’s manual for detailed instructions.
  3. Slide the filter out of its slot.
  4. If your window AC has a reusable filter, use a soft brush or vacuum to remove any dust or debris. If necessary, clean the filter with warm, soapy water.
  5. If you have a disposable filter, replace the filter as per the manufacturer’s guidelines.
  6. Make sure the filter is completely dry before putting it back to prevent condensation and mold growth.
  7. Reinstall the filter.

Once you’ve cleaned or replaced the air filter, please plug your window AC back into its power source and turn it on to see if the issue has been solved.

#2 Clean the Coils

In my experience, dirty coils can also cause a window AC to short-cycle.

Your window AC works by drawing in warm air over its evaporator coils, which contain refrigerant. These coils absorb heat and transform the refrigerant into gas. Then, the cooled air is circulated into the room, and the gas is sent to the condenser coils outside, which release the generated heat and convert the refrigerant back into liquid.

Unfortunately, if the coils in your window AC are covered in dust, they can affect the cooling system and cause the compressor to work harder and overheat, leading to short cycling.

Follow these simple instructions to clean your window AC’s coils:

  1. Unplug your window AC from its power source.
  2. Remove the front cover and outer casing to access the evaporator and condenser coils. The process of accessing the coils can vary depending on the specific model you own, so please refer to the manufacturer’s manual for detailed instructions.
  3. Use a soft brush or vacuum to clean the coils.
  4. Reassemble the window air conditioner and plug it back into the outlet.

Turn on your window AC to see if the short-cycling problem has been solved. If it persists, then there’s probably an issue with the power supply. Read on to learn more.

#3 Check for Power Issues

If you’re struggling with a window AC that keeps cycling on and off, I recommend checking for power issues.

You see, overloaded circuits, faulty wiring, and intermittent power issues can cause voltage fluctuations that result in short-cycling problems.

To check for power issues, start by examining the power cord of your AC. If you notice any signs of damage, such as frayed wires, please replace it with a new one.

Damaged Power Cord
If your window AC is short-cycling, inspect the power cord.

If the power outlet is faulty, it could also lead to intermittent power issues, causing your window AC to short-cycle. To check the outlet, simply plug in a different device and see if it works. If it doesn’t, you’ll need to call an electrician, as there’s probably a more complex electrical problem in your home.

It’s also important to avoid plugging multiple devices into the same outlet to prevent an electrical overload. Don’t forget to plug your window AC directly into the outlet to prevent voltage drops. You should never use an extension cord.

#4 Inspect the Thermostat

If your window AC keeps cycling on and off, you’ll need to check the thermostat.

The thermostat is responsible for measuring the room temperature and controlling your window AC. However, if the thermostat is set very close to the current room temperature, the unit will frequently cycle on and off.

For instance, if you set the thermostat to 70ºF and the room temperature is at 71ºF, your window AC will turn on to lower the temperature by just one degree, then quickly cycle off.

So, to fix the short-cycling problem, make sure that the thermostat setting is not too close to the current room temperature.

However, if the issue persists, there’s probably an issue with the temperature sensor, which is typically near the evaporator coil. Carefully clean the sensor with a soft cloth and look for any visible signs of damage.

It’s also important to ensure the sensor is not touching the evaporator coil. If it is, the sensor could mistakenly signal that the desired temperature has been reached, causing the window AC to shut off prematurely.

If you determine that the temperature sensor is faulty, you’ll need to replace it with a new, compatible one.

Find any replacement part:

#5 Check Refrigerant Levels

From what I’ve seen, low refrigerant levels can also cause a window AC to cycle on and off.

The refrigerant is a chemical substance that flows through the coils of your window AC in the form of gas or liquid to absorb the heat from the room and release it to the outside.

If the refrigerant level is too low, your window AC will cycle on but then turn off prematurely due to the evaporator coil freezing over, which alters the temperature sensor readings and interrupts the cooling process.

Low refrigerant levels can also lead to higher energy bills and put extra strain on the compressor, so it’s crucial to address the issue immediately.

Keep in mind that working with refrigerants can be both risky and challenging. So, if you suspect that your window AC is low on refrigerant, you’ll need to call an HVAC technician. They have the necessary tools and expertise to detect any leaks and recharge the refrigerant to the correct level.

#6 Inspect the Compressor

If your window AC is still cycling on and off, then there’s probably an issue with the compressor.

You can think of the compressor as the heart of your window AC, as it is responsible for circulating the refrigerant through the coils to cool your room effectively. Unfortunately, if the compressor overheats or malfunctions, it can cause the unit to short cycle.

window ac compressor
If your window AC cycles on and off, check the compressor. Image from Sears Part Direct.

To check the compressor, unplug your window AC and remove the outer casing using a screwdriver. Look for any signs of damage and make sure it’s not clogged with debris. If necessary, clean the compressor with a soft cloth.

However, if you determine that the compressor is not working, I recommend consulting your warranty status and considering the age of your window AC. Replacing the compressor is a costly process that requires the services of a certified HVAC technician. It’s often more cost-effective to replace the entire unit.

#7 Consider the Size of Your Window AC

If you’ve tried all of the fixes above, but your window AC keeps cycling on and off frequently, it’s likely because it’s too large for your space.

An oversized window AC will cool the room very quickly and then shut off. The short cycling problem not only results in inefficient operation, but also increases your energy bills and shortens the unit’s lifespan.

Unfortunately, if your window AC is too large, the best solution is to replace it with one that matches your space.

To select the right window AC, you’ll need to consider the size of your room and the cooling capacity. Air conditioners typically need about 20 BTUs for each square foot. So, if you have a room that’s 150 sq ft, you would need an air conditioner that’s around 3000 BTUs.

Use our free window AC size calculator to ensure you purchase the right unit!

Wrapping Up: Stop Your Window AC From Cycling On and Off

That about covers it! Hopefully, now you know how to keep your window AC from cycling on and off.

Remember that if your window AC is short-cycling, you’ll need to clean the air filter and coils. It’s also important to check the outlet and power cord, inspect the temperature sensor, and select the right settings.

If the issue persists, don’t forget to call an HVAC technician to check the refrigerant levels and examine the compressor.

Thank you so much for taking the time to read this guide. If you ever experience a different issue while using your window AC, please check out our related posts below.

Good luck!

I've been helping homeowners with appliance repair since 2016. Starting out as an enthusiastic amateur, I've since worked with many Appliance, HVAC, and DIY experts over the last 7+ years. My mission is to help fix your appliances and prevent future issues - saving you stress, time, and money. Visit my author page to learn more! Read more