Why is my Aircon Coil Freezed?

Freezing up of the aircon coil can often lead to many complications which ultimately reduces optimal functioning and efficiency of the AC system. I will be going through the top and most common reasons on why your AC coil might be freezing up.


How to tell if my AC coil is freezing?

The most obvious telltale sign would be that your aircon is not cooling the room as efficiently as usual. Check on the flow of air through the supply air registers. It may be a frozen AC if the air is warm or if there is no air at all. There will also be a buildup of ice on the indoor or outdoor coils. If you find that your aircon is freezing up, the immediate thing to do is to switch off the air-conditioning system.

Here are some common reasons that cause your aircon coil to freeze:

Dirty Air filters

Dirty air filters will hinder airflow in and out of the aircon unit. Regular and continuous airflow is needed to prevent humidity from settling onto aircon coils. If air is not circulating around the coils, the coils will get very cold and eventually freeze up. Moreover, ice accumulated will cause blockages in the system and reduce condensation flow out of the unit.

If you have identified this problem with your aircon, you can consider DIY whereby you turn off the power to your AC and wait for it to defrost. Meanwhile, you can purchase new air filters which can be easily found and are cheap as well! Change the dirty air filters in your AC unit and you need to maintain your air filters to not become dirty and clogged up. Do take extra note to change your air filter regularly. 

Damaged Thermostat

The thermostat is very important in working well with your aircon as it regulates the temperature and controls the level of intensity the AC has to work at in order to maintain consistent temperatures. When there is a sudden increase or decrease in surrounding temperatures, the thermostat will regulate the temperature back to normal levels, preventing the AC coils from being extremely hot or cold.

When the thermostat is damaged and fails to control the aircon correctly or detects the wrong temperature, it potentially damages and wears out the system by working the Aircon for excessive amounts of time. You might have a broken thermostat if the aircon unit is unable to keep a consistent and regular temperature or if the temperature drops all of a sudden.

When thermostats are damaged and undiscovered, the AC unit could overwork and cause AC coils to freeze. Do perform frequent checks and maintenance of the thermostat as well as other Aircon parts to ensure that your AC unit is in good condition to function optimally.

Refrigerant Leaks

Refrigerant is the chemical running through the AC coil. The chemical helps to absorb heat by regulating pressure and temperature. It is crucial to have sufficient refrigerant in order for your AC to function optimally. If the refrigerants get low or leak, the fall in pressure and temperature will cause it to absorb more heat than it is supposed to. Excessive heat loss occurs due to refrigerant lines freezing over, eventually causing the coils to freeze. 

Leaking refrigerant is harmful to the environment and illegal in some countries, therefore it is not wise to fill up the coil with more refrigerant. If you discover a leak in your refrigerant it is highly recommended to get a professional in the field to repair the leak and change out the coils. It is imperative that you contact a specialist with minimal delay as leaking refrigerant could possibly damage the aircon system as well. Click here to find out why your aircon is leaking.

Blocked Condensate Lines

Condensate lines in your Aircon system drains away excessive moisture built-up as a result of humidity. Excessive moisture condensed into water travels to the floor drain through the drain pipes. This makes sure that there is no accumulation of water in the AirCon system.

When the condensate line is clogged, water in the drain pipes will be stuck and accumulate and will eventually freeze resulting in the obstruction near the evaporator coil. This causes the AC unit to cool which leads to the coil being freezed. 

The nearer the obstruction of the pipe is to the evaporator coil, otherwise known as the coldest part of the Aircon unit, the higher likely the coil will freeze.

Damaged Blower Fan

The blower fan regulates the temperature of your AC by circulating air around the coils, bringing in cold air from the environment and releasing warm air.

The fan makes sure that the AC does not get too cold and freeze up. If the fan is damaged there will be a lack of airflow. Condensation results due to accumulation of moisture, eventually causing AC coils to freeze. 

With insufficient heat supplied, the condensate drain line will be clogged up as well due to condensation. It is thus very important to make sure that the blower fan is fixed or changed to prevent further complications in the AC system.


So, what can YOU do when you discover that your AC coils have freezed up? Immediately switch off power connected to the AC to let the ice in the aircon melt and clear the surrounding water leakage if applicable.

Contact an Aircon professional immediately. It is crucial that you fix the issues faced immediately to prevent further complications that could potentially compromise optimal functioning of your AC system in the future. Do conduct regular Air con Servicing to prevent issues such as Aircon leaking. 

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