Freezing A/c is a very common complaint made by homeowners. But what causes an A/c to freeze? Let’s take a look at the reasons-

Insufficient air flow: This is generally caused by dirty filters. If you are not changing your filters on regular intervals, then they will become infested with a layer of dirt. Sufficient air will not be able to pass through the mesh of the filter in such a case. The hot room air is taken in through the ducts and passed through the filter. They reach the evaporator coil for cooling. If enough air is not passing through the filter then sufficient air will not be available at the evaporator coils for cooling. The evaporator coil has the cool refrigerant inside. This absorbs the heat in the room air and makes it cool. The refrigerant will not absorb enough heat from the air and its temperature will drop down over time. This will cause the evaporator coil to freeze.

Low on refrigerant: If the refrigerant level of your air conditioner is low then this can also cause the evaporator coil to freeze. A low level of refrigerant will cause a lower pressure inside the coil. This will lead to icing of the coil. The Freon level of your A/c has gone down a bit and it is being forced to expand the same amount. This will cause a cooler temperature. As soon as the temperature within the coil drops, the moisture and air that comes into contact with it will start freezing. This will lead to an ice up.

A/cs are designed to operate in a specific temperature range. If your outside temperature is say around 62 degrees, then the pressures inside your system will also drop. This often leads to a freeze up in most central air conditioner.

Mechanical failures: Sometimes the reason could be very minor such as a kink in your refrigerant lines, a non-functioning blower fan or the fan is dinged and out of balance, or a clogged filter dryer. All these can cause a change in pressure and cause your central air conditioner to freeze up.