When AC coils freeze, it may be due to a lack of airflow, improper draining, or a refrigerant leak. AC coils, also called evaporator coils, are among the main components of your AC unit. The coils remove the heat and humidity as warm air passes over them, and your AC system distributes cooler air into your home. When heating your space, the coils create heat that your blower fan can send.
The coils work alongside the condenser, which condenses the humidity into the water for elimination. If there is no humidity in the air for the coils to remove, or if the airflow is obstructed, ice can develop in your unit. AC coils can freeze any time of the year, so check and maintain your system regularly.
Common Causes of a Frozen Evaporator Coil
A variety of issues can cause your evaporator coil to freeze over. These could be problems stemming from within your AC system or outside, including:
Dirty Evaporator Coils
Evaporator coils can collect dirt and debris over time, hampering the heat exchange. Dirty coils can’t absorb heat from the air, so the condensation becomes too cold and freezes up.
Dirty Air Filters
A dirty air filter prevents the coils from absorbing enough heat from the air to function correctly. It can also spread dirt and congest other parts of your AC system, including the evaporator coils.
Low Refrigerant
Low refrigerant makes your AC system overwork, which can cause the coils to freeze. In this case, you may have a leak or insufficient charge.
Clogged Drain Line
Condensation on the evaporator coils is a natural part of how the coils work. Too much condensation can form and freeze if the drainpipe is clogged or malfunctioning.
Freezing Outdoor Temperature
If the outside temperature is too low, your system will have no heat from the air to absorb, which can cause the condensation on the evaporator coils to freeze.
How Do I Fix a Frozen Evaporator Coil?
Having your AC system professionally inspected and serviced is the best way to find and fix what’s making your coil freeze over. Your unit may have instructions for de-icing, or you can try some safe methods such as these:
Thaw The Coils
Turn off your AC or the system to “fan-only” for up to 24 hours. If your system has a heat pump, turn it on defrost mode.
Check The Air Filters
Make sure your air filter is new and clean. Replace if needed so that the air can flow properly.
Clean The Coils
The easiest way to take care of your evaporator coils is to let an expert handle the cleaning. If you prefer to DIY, though, you can follow these steps to clean the coils yourself:
- Turn off your AC system at the panel and breaker.
- Find the coils near the blower fan in the air handler.
- Spray coil cleaner or a solution of household cleaning detergent and warm water on the coils.
- Let the solution sit for 10 minutes, then wipe away the grime with a soft cloth.
Call a professional AC service to inspect your unit if none of these steps work.
How Do I Prevent AC Coils From Freezing?
Preventive maintenance is the best way to prevent your AC coils from freezing. Check and change your air filters every 60-90 days. Have a professional HVAC technician inspect and tune up your AC unit at least once a year. Let an expert check your system before summer when you’ll likely use it more. This helps ensure that your AC works efficiently and keeps you comfortable.
