What Causes My A/C Coil to Freeze Up?

Your A/C coil can freeze up. If this happens, there is something wrong with your HVAC system. There are a few things that may cause this, such as:

Thermostat Error

If your thermostat isn’t running correctly, it will give the wrong signal to your AC. As a result, your AC won’t run properly either. Also, if the unit runs too hard and delivers too cold air, there is a chance its coil might freeze. Therefore, it is essential to keep the coils clean to function correctly.

Dirty Air Filters

If your filter has too much dirt buildup, the cold air won’t be able to flow through as easily. As a result, the coil will get too cold if the cold air fails to circulate. In time, this will cause the A/C coil to freeze up. The entire A/C unit will shut down when the coil freezes until the coil thaws out.

If you don’t keep up with regular filter changes, your air conditioner will have to work harder to circulate cold air. This puts unnecessary strain on the system and can lead to a breakdown. To avoid this, change your filter every 1-3 months.

Blocked Condensate Line

Your AC absorbs excess moisture from the air to deliver air at a more comfortable humidity. The extra moisture will run to the drain through the condensate line. If the line gets blocked, the cold water will remain there. If the blockage is near the evaporator coil, it will get too cold. 

Eventually, ice will start to build up. The ice will continue to grow until it completely blocks the airflow. If this happens, your AC will stop working.

If you notice your AC isn’t working as well as it should be, check the condensate line to see if it’s blocked. If it is, clear the blockage and your AC should start working again.

Malfunctioned Fan Motor

When your fan motor breaks, the air will not push through. As a result, the coil will get too cold and freeze up eventually. Dirty motor blades may also cause this issue, even if the motor itself is fine. You can try cleaning the blades with a brush, but you’ll need to replace them if they’re too dirty.

If your evaporator coil is frozen, it won’t be able to absorb heat from your home. This will cause your air conditioner to work less efficiently and your energy bills to go up. A frozen coil can even cause your air conditioner to stop working altogether in extreme cases.

Refrigerant Leak

The refrigerant in your AC unit should run in a closed-loop. If the line is leaking, some refrigerant will come out and cause a shortage in the loop. Since your AC will not have enough of this chemical, your AC will absorb more heat than it should. Hence, the temperature will drop, and ice will start to appear.

Doing nothing to your frozen coil may lead to more severe consequences. For example, your compressor might eventually break, so you will need to replace it. There will also be serious water damage to your house. So if you find your AC coil freezing up, here is what you must do as soon as possible:

  1. Turn your AC system off to stop the freezing.
  2. Let the ice melt. You can use a hairdryer to speed up the process, but don’t try chipping off the ice because it might damage your coil.
  3. Clean up the water from the melting ice before it damages your walls or furniture.
  4. Find out what is causing the issue and resolve it as soon as possible. If you can’t seem to handle it yourself, get professional help.
  5. After getting all the problems fixed, continue paying attention to your AC and see if the problem recurs.

If the problem recurs even after repairs, then there must be another reason why your AC coil freezes up. Ask your technician to perform a thorough inspection to determine the culprit.

There is no need to panic if you find ice around your AC coil because it is probably just a small problem. However, underestimating the issue might create significant issues in the future.



ECM Air Conditioning, with its headquarters located in Boynton Beach, FL, provides air conditioning services within Palm Beach County, Broward County, Martin County, and St. Lucie County. If you’re looking to have a new HVAC system installed, we’re on-call and ready to assist you. So if you’re in need of an HVAC installation, don’t hesitate to contact us today to schedule an inspection! Our HVAC installation experts will check your ductwork, measure, check wire sizes, and more before making recommendations to ensure maximum efficiency and comfort. Call us at 561-295-1763 or contact our HVAC installation team online by clicking here.


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