How Do I Fix My AC From Freezing Up?

An air conditioner freezing up is a very common problem, especially in the first few hot days of summer. There are many reasons for air conditioners to ice up. My customers that call that time of year seem to always think that there AC is low on Freon, which is just one of the reasons for ice to be forming on AC units.

Although we may not be able to fix your AC freezing problem I can help you eliminate most to the causes before you have to call an HVAC technician. Then maybe you won’t have to pay for a service call. Let’s hope. A frozen AC will not fix itself. We have to do a few things first to sort of chase down the cause.

One of the best indications of an AC freezing up inside is lack of air flow coming out of your registers. When an air conditioner freezes up it blocks the air from going through the furnace. Just like a plugged air filter. So lets remove the filter just for a while here while we check some other things.

What’s A Quick Fix For An AC Freezing Up?

With the air conditioner running the icing problem is only going to get worse. The next thing to do is turn off the compressor. The best way to do that is to go to your thermostat and turn the system to “OFF”.

And while you are looking at your thermostat, turn the fan to “ON”. Next, go from room to room and open all the registers. Make sure your return grilles are not blocked by furniture or whatever. You have to have all the air flow you can get through your system.

The fan will do a pretty good job of melting the ice. Especially since the compressor is off now. With the fan running you will begin to notice that the signs of ice will begin to melt away. You may even see water beginning to drip out on to the floor. Not much you can do about that except keep it mopped up if you feel it’s necessary.

This may take some time depending on the thickness of the ice on the coil. Up to several hours. If access to the coil is easy then you may be able to look inside and see the ice on the surface of the coil.

With the ice melted and the air flow restored to normal you can now turn the air conditioner or compressor back to the “COOL ON” position and the fan to “AUTO” unless you want to run your fan continuously.

Now you just need to monitor the system to see if ice begins to form again.

Why Does My AC Keep Freezing Up At Night?

Air conditioners will freeze up at night more readily than in daytime hours because of the lower outdoor ambient temperatures. When the outside unit or condenser cools down at night, that temperature translates to a lower temperature at the indoor coil.

iced up indoor coil

Anytime the temperature of the indoor coil drops below the freezing point, ice can then begin to form on the coil. So if you like to sleep in a cold room that you have to create by turning your air conditioner down below 70 degrees at night you run the risk of freezing up your air conditioner.

There are so many conditions that exist it’s hard to mention them all here. Everything from size of AC unit compared to size of your home and insulation and run time. The list goes on and on and can really only be diagnosed by an experienced professional.

It has nothing to do with the age of your HVAC system, even a brand new AC unit can freeze up. Brand name has absolutely nothing to do with icing problems. If you read this entire article you know more than most people about why air conditioners ice up. I hope it’s been helpful.

Chad Peterson

Chad Peterson is a veteran of the HVAC industry since 1977. "I like to explain heating and air conditioning problems in a way the average home owner can understand. "

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