Window AC Blowing Cold Air, Then Stopping? Here’s Why

Frozen Window Air Conditioner

Is your Window AC blowing cold air and then stopping for no apparent reason?

That sucks! The issue affects thousands of people daily all over the world, leaving them confused, sweating, and desperate for a solution.

I know how annoying it can be to have your Window AC blowing cold air and then stopping out of the blue, but don’t worry; you’ve come to the right place for answers. Below, you’ll find the most common causes behind the situation and 4 simple fixes you can try to solve the problem.

When your Window AC is blowing cold air and then stopping, I recommend you determine the source of the malfunction, check the thermostat, and observe the compressor carefully. You must also consider fan issues as the possible culprit.

Read on to get your Window AC blowing cold air continuously!

Why trust us? This article was written by Craig Anderson and Alan Stephens.

Craig has helped thousands of other homeowners repair their appliances since 2016.

Alan is one of our resident appliance repair experts with over 20 years of experience in both commercial and residential HVAC projects. He has all 3 HVAC license certifications in North Carolina (H-1, H-2, & H-3-1). Since 2004, he runs his own company, Eco Green Air Inc in Raleigh, NC.

Why Your Window AC Isn’t Blowing Cold Air Constantly

In my experience, there are many possible explanations behind a Window AC that blows cold air and then stops. From something simple, like a bad thermostat, to a more complex and expensive problem, like a faulty compressor or fan.

Here are some steps I recommend you follow to help you get to the bottom of the problem as quickly as possible.

#1 Pinpoint the Source of the Issue

When trying to determine why your Window AC is blowing cold air and then stopping, my usual advice to get started is to try to pinpoint the source of the issue.

Assess whether you’re dealing with a fan malfunction or if the problem lies with a different component/section of the unit. Observe how your Window AC works.

Is the fan stopping, but the compressor is still activated? Does the compressor seem to start and then shut off sooner than it should? You must ask yourself all these questions to find the specific component that’s acting up and save time and effort.

#2 Check the Thermostat

When you have a clearer idea as to why your Window AC is blowing cold air and suddenly stops, the next step I recommend you take is to check the thermostat.

The thermostat is responsible for translating the temperature you dial into commands for your AC to adjust its settings and deliver the results you want. I’ve found that when the thermostat fails, your Window AC will not be able to perform normally and might even stop blowing cold air suddenly and before reaching the desired temperature.

Window AC thermostat
A faulty thermostat can cause your Window AC to work abnormally.

Solution: To rule out any thermostat-related issues, try adjusting your Window AC’s temperature to the lowest possible setting and see what happens. Then, try using the hottest temperature setting and repeat the test.

You should only try the abovementioned process briefly as a diagnosis tool. Under normal circumstances, setting your Window AC over or under 20 Fahrenheit relative to ambient temperature will not only overstress the unit but also drive up your electricity bills – so I strongly advise against it.

#3 Watch the Compressor Closely

The next possible reason why your Window AC is blowing cold air and then stopping is a compressor-related issue.

The compressor inside your Window AC helps pump the refrigerant liquid through the unit’s coils. Excess moisture and heat are removed as the refrigerant liquid flows through the coils, and cool air is blown out of the appliance.

If the compressor fails in any way, the cooling process is severely affected, which can explain why your Window AC is blowing cold air and then stops.

Solution: Watch and listen to the compressor closely. See if the AC fan stops while the compressor is running, and try to notice anything out of the ordinary as the compressor hums.

Also, look for frosting on the AC unit’s coils, which typically indicates a compressor and fan problem.

If either the compressor or the fan inside your appliance is failing, you’ll need to replace them. Depending on how well-versed you are in terms of DIYs and HVAC systems, you may be able to handle the task yourself. However, if you’re unsure about the process and are unwilling to risk doing further damage to your Window AC, calling a certified technician is what I’d recommend.

Depending on your Window AC’s make and model, the cost of repairs and cost of labor will vary.

#4 Consider Fan Issues

Last, let’s consider fan issues as another possible reason why your AC is blowing cold air and then stops. The fan plays a key role in how your Window AC blows cold air, so any malfunction can affect the entire process and leave you sweating on a sweltering day.

In most cases, obstructions and debris inside the fan’s “squirrel cage” can stop it from spinning. However, there are also instances where a bad capacitor fails to supply enough power for the fan to work normally.

Window AC fan
Ensure there’s nothing preventing your Window AC’s fan from spinning freely.

Solution: Inspect the fan and the squirrel cage to see if you can spot any debris that might be getting in the way. Provided you don’t see any obstacles but notice the fan is spinning slowly or not at all, a capacitor is, in my opinion, the next most likely culprit.

Replacing a Window AC fan’s capacitor is no easy task, and sometimes, you’ll be better off replacing the entire fan instead of a single component. Please do not hesitate to contact a technician you trust to answer any questions you have and ask about the repair process.

Getting Your Window AC Back to Normal

That about covers it!

When your Window AC is blowing cold air and then stops, it’s understandable that the first thing that comes to your mind is that the appliance is done for, and you’re in for a fortune’s worth of repairs.

Luckily, as I hope this piece has helped you better understand, addressing the most common causes behind a Window AC blowing cold air and then stopping can be easy and quick. More often than not, something as simple as removing debris and other obstacles from the fan’s squirrel cage will do the trick.

Thanks for reading. If this article was useful and answered your most burning questions, please check out our other resources and free guides below and consider subscribing to our newsletter.

Have a cool day!


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