My Air Conditioner Is Frozen! What Happened?


A lack of airflow coming from inside vents is one of the first signs of a frozen air conditioner. Many things, including improper maintenance, can lead to this condition, which causes ice crystals to form on the coils.

The evaporator coil removes heat and moisture from the air. If the climate is humid, much of the water vapor condenses inside the air conditioner and collects in a drip pan before flowing into a floor drain. When the drain is blocked, the water backs up and freezes around the coil.

A common problem that causes the coils to freeze is low refrigerant levels. If the unit was not charged properly when it was installed or the system has developed a leak, the evaporator coil becomes too cold. If this happens, you should call a HVAC technician to find the leak, repair it and recharge the system.

Some homeowners close the registers in empty rooms to save energy. This is effective to a point, but if too many registers are closed, the system is under stress and the coils could freeze.

Something as simple as a dirty air filter restricts airflow through the system. The coil requires adequate amounts of hot, humid air to work properly. This is completely preventable if you remember to clean or change the system’s air filters every month.

If you do have a frozen air conditioner, the first thing you should do is turn the unit off to prevent compressor damage. Check the condensate drain and clear away any debris that may be blocking it. Turning on the AC fan and using a blow dryer on the evaporator coil will help speed up the melting process. Do not turn the air conditioner on until all the ice has melted and you are sure the drain is clear.

Routine maintenance and annual inspections by a qualified HVAC specialist can prevent your air conditioner from freezing up and ensure that it keeps working at peak performance during the hottest days of the year when you need it most.

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