Window AC Keeps Tripping Circuit Breaker? Here Are the Causes

Click! Did your circuit breaker trip when your window AC turned on?

Or maybe your window AC ran for a while, but the circuit breaker eventually tripped while your AC was running.

Your window AC has one problem or another – depending on the way that your circuit breaker tripped.

In this article, I’ll go over all the causes of a tripping window AC circuit breaker. I’ll also explain how to fix a window AC that’s tripping its circuit breaker – no matter what the cause is.

Bad Capacitor

bad ac capacitor swollen top

A bad capacitor will stop a window AC dead in its tracks. A bad capacitor will also often cause a window AC to trip its circuit breaker when the AC tries to start up.

So what is the capacitor for, anyway? And how does a bad capacitor cause your circuit breaker to trip?

The window AC’s capacitor gives an extra “jolt” of energy to the compressor and fan motor to start up.

If the capacitor goes bad, the compressor or fan motor will stall in place and overdraw amperage from your home’s electrical system – causing the breaker to trip.

So how do you know if your window AC’s capacitor is bad? And what should you do if your window AC capacitor goes bad?

Here’s the solution:

To find out if your window AC’s capacitor is bad, you’ll need to check it with a multimeter.

Unplug your window AC, then remove its paneling and enclosure to access the capacitor.

If the capacitor is swollen up, then it is bad.

But your capacitor can be bad even if it’s not swollen – so you should test it with a multimeter.

Discharge and disconnect the wires from the capacitor, then use the capacitance test setting on a multimeter to test the capacitor.

For a complete step-by-step guide to checking your AC’s capacitor, check out my article below:

Restricted Airflow

An airflow restriction in your window AC will cause it to work harder and trip its circuit breaker.

Why does that happen?

An airflow restriction will cause all the components in your window AC to work harder. This leads to all sorts of imbalances and side effects in your window AC – such as a frozen evaporator coil or an imbalance in refrigerant pressures.

Eventually, all these imbalances may cause your window AC to overamp and trip your circuit breaker.

So what do you do if your window AC has restricted airflow?

If your window AC has an airflow restriction, you’ll need to find the source of the airflow blockage and remove it.

Look for things such as embedded debris in your evaporator or condenser coils.

You also need to remember to clean your window AC’s dirty air filter and condenser coil – which I’ll go over below.

Dirty Air Filter

Clean the window AC air filter

While seemingly innocuous, a dirty air filter will cause your window AC to trip its breaker.

How does a dirty air filter cause your circuit breaker to trip?

One way that a dirty air filter will cause a window AC’s circuit breaker to trip is because of increased amp draw from the blower motor.

The blower motor will overheat and draw more amperage if the air filter gets really dirty. The increased amp draw may eventually trip your window AC’s circuit breaker.

If your window AC’s air filter is dirty, you need to remove the air filter, clean it out, then reinstall it.

Most window ACs have reusable mesh screen air filters. These air filters are designed to be used over and over again so you don’t need to buy new filters for your window AC.

The best way to clean your window AC air filter is to rinse it out with water in your sink. Spray the backside of the filter with water to dislodge the dust from the air filter.

I recommend using the spray setting that most kitchen sink faucets have – it has more pressure so it will clean the filter out thoroughly.

Spray the back of the filter down in a side-by-side motion until you cover the entire area of the filter.

Finally, let the filter dry out before reinstalling it in your window AC.

Dirty Condenser Coil

A dirty condenser coil will cause your window AC to trip its circuit breaker because of high refrigerant pressure.

A dirty condenser coil won’t cause your window AC to trip its breaker right when it turns on – it usually takes a minute or two.

This is because your window AC isn’t able to sufficiently reject heat. The insufficient heat rejection causes the refrigerant pressure to build up, which causes the compressor to overamp.

The over-amping compressor is what causes the breaker to trip – but it’s ultimately caused by a dirty condenser coil.

So what do you do when your window AC’s condenser coil is dirty?

If your window AC’s condenser coil is dirty, you need to clean it out.

Clean out your window AC’s condenser coil by spraying it with a garden hose. This method works best if the condenser coil only has a layer of dirt on it.

If your condenser coil is clogged up and full of debris, then you should use an AC coil cleaning solution to dislodge the debris and clean the coil.

One word of caution: Don’t use a pressure washer to clean your AC coils. A pressure washer is too strong and will damage the fins on the coils.

Bad Compressor (Shorted or Grounded Out)

A grounded, shorted, or hard starting compressor will cause your window AC to trip.

So how does a compressor go bad in the first place?

A window AC compressor can ground or short out when it overheats.

Here are a few things that will cause your compressor to overheat and (eventually) short out:

  • Dirty condenser coil
  • Dirty air filter
  • Refrigerant leak

So how do you know if your window AC’s compressor is bad?

One way to figure it out is to test your compressor with a multimeter.

However, if your window AC’s compressor is bad, the entire unit is pretty much toast. It’s much cheaper to just get a brand-new window AC rather than get its compressor fixed.

Loose Electrical Connection or Bad Wiring

Loose and/or bad electrical wiring will cause your window AC to overamp or short out and trip its circuit breaker.

If you see sparks in your window AC or at its outlet, then there’s a good chance that it has a loose connection or has shorted out.

So what do you do if your window AC has a loose electrical connection or bad wiring?

If it’s something simple like a loose power cord, then ensure that the power plug is inserted fully into the electoral outlet.

But if the power cord or power plug itself has gone bad or has exposed wiring, then you can replace it with a new power cord or plug.

Check out this video below from LRN2DIY for more information on how to replace a bad power cord.

Bad Breaker

If everything on your window AC is working ok, then it could be the breaker itself that’s bad.

One way to figure out if your circuit breaker is bad is to plug your window AC into a different outlet in a different area of your home.

If a different circuit breaker trips, then something is wrong with your window AC.

If your window AC starts up and runs without tripping a different breaker when you move it to a different outlet, then the old breaker is bad.

So what should you do if your window AC has a bad breaker?

If your window AC has a bad breaker, then you’ll need to replace the old bad circuit breaker with a new one.

Check out this video from Silver Cymbal for more information on how to replace a circuit breaker.

What Causes a Circuit Breaker to Trip?

A circuit breaker trips when too many amps are drawn from an electrical circuit.

In most homes, multiple outlets are usually tied back to one breaker.

So if you plug large appliances into multiple outlets that are on the same breaker, the circuit breaker will trip if the sum of the amperage drawn from the outlets exceeds the rating of the circuit breaker.

For example, consider a window AC that draws 7 amps and a space heater that draws 12.5 amps. If they are both turned on, they will consume 7 + 12.5 = 19 amps.

If these two appliances are plugged into outlets that are tied to the same 15 amp breaker, 19 amps exceed the breaker’s rating of 15 amps, so the breaker will trip if the window AC and space heater run at the same time.

I’ve seen a similar situation happen recently:

The outlet that a window AC was plugged into was tied to the same breaker as the bathroom outlet. As a result, if someone operated the hair dryer in the bathroom while the window air conditioner was turned on, the circuit breaker would trip!

To fix this, you would ideally want to plug the window AC into a different outlet – one that’s not connected to the same circuit as other appliances that draw substantial amounts of current.

Hi, my name is Trey Lewis and I’m the founder and chief editor at HVAC Training Shop. My goal for this website is to help homeowners troubleshoot and maintain their home’s HVAC systems. Whether it’s changing an air filter, troubleshooting a blower motor, or just buying a new humidifier, I want to make sure that you’re covered.

2 thoughts on “Window AC Keeps Tripping Circuit Breaker? Here Are the Causes”

  1. I have a 24k btu 220 window unit. It was working great. Its just under a yr old. I took it outside and cleaned it thoroughly with water sprayer. Put it back in hole and plugged it in. It instantly popped breaker. 1st try i believe i powered it on. Next few tries, i didnt even get that far. Assuming there was still water or moisture, i let it sit 10 hrs with dehumidifier nearby running and tried it again. No luck. What did i mess up? Hard to believe this ac needs to be junked over something simple.


Leave a Comment