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Common Problems

Why Is My AC Freezing Up: Common Causes and Solutions

Aircon Freezing: Common Reasons and Solutions 

How to Prevent Frozen Air Conditioners

Ice isn’t Cool

Aircon maintenance is key to keeping your unit in good working condition for a long time, which is why when your AC unit starts freezing up, it can cause frustrating issues for your unit. 


A frozen AC is easy to spot. Your unit may not cool the room as well, you’re experiencing leaking water even when turned off, or you have a thick layer of ice around the filter and the cooling coils. Your AC unit may also turn on and off repeatedly, as the components shut down with the presence of ice.


What to do when your AC unit freezes up? Before you dial for professional services, check first if the problem could be easily solved at home. Knowing how to clean important parts of your AC unit can save you from costly and unnecessary repairs.

Aircon Freezing: Common Reasons and Solutions 

You may find yourself asking, Why is my AC freezing up? There can be a variety of reasons that make an AC frozen. An AC freezing up is indicative of an issue with cleaning, or a problem with its components. Issues with the airflow may be causing humidity to get trapped in your unit, or perhaps your refrigerant needs topping up.


The number one reason for frozen air conditioners can actually be remedied at home with a simple cleaning. Dust build up in the filter and vents is the number-one culprit for problems with your AC freezing. However, more serious issues, such as those pertaining to mechanical problems and hardware, would require servicing by a professional technician.


Modern room with split-type air conditioner
Many homeowners use their air conditioners to keep their rooms cool during hot days.

Blocked airflow

Air conditioners require good air circulation to prevent humidity and condensation from freezing inside the unit. Blocked airflow traps in cooled air, causing condensation to freeze up and form ice in and around the compressor coils. Blocked or restricted airflow is indicative of an internal or external problem with your unit. 

Collapsed Duct in Central AC

If you have a central air conditioning unit, you may check for any ducts that might have an obstruction that is causing restricted airflow. You might find one or two collapsed ducts can cause your entire cooling system to malfunction. 


Even if your AC unit is working properly, a disruption in the airflow causes cool air to  stay within your cooling system, freezing up any water vapor in the process. To fix, turn off your AC unit, and allow the ice to thaw. Then, remove any obstructions in the ventilation system, and clean any debris that you suspect may be causing the poor ventilation.

Blocked Ventilation

Blocked airflow may be caused by an external issue. Check your outdoor AC unit and see if the vents are cleared of any dirt or debris. Move away any large items and fixtures from your unit, which may be restricting airflow to the vents. 


Check your coils for any debris that may be blocking airflow. Both your indoor and outdoor components need to be well-maintained and clear of any obstructions. Brush away any loose dirt at reach, but make sure your AC is turned off and thawed out before you do.


Modern living room with wooden shelves and brown sofa.
Air conditioners require maintenance at least once a year.

Busted Blower Fan Motor

If your vents are clear, check the internal structure of your AC unit, and see if the fan motor is working properly. If the blower motor isn’t working at all, you will need to have the parts replaced in a service center. Alternatively, a clunking or whirring sound may indicate your fan motor is breaking down, and needs to be replaced.


If the fan is working, but in a very low power setting, it may be due to too low voltage for the motor to run smoothly. This causes the fan to keep air within the air conditioner body instead of blowing away from the unit.


Industrial cooling fans in red and blue
Cooling fans are essential parts of any device that prevents overheating with adequate air circulation.

Dust buildup

Rarely and improperly cleaned units can trap dust and oils from the surrounding air, causing a build up of grime that can clog the air filter and coat the evaporator coil, causing poor airflow around within the unit leading up to freezing. 


Dust build up is the most common cause for ice forming inside your unit. Just as with any blockage, clearing out the grime around your filter and evaporator coil will usually do the trick to get your AC unit up and running again. 


Mechanical problems

If cleaning the filter and the exterior of the unit didn’t help alleviate the issue, the problem might be with the AC unit’s hardware. Although difficult to diagnose at home, mechanical problems might cause some clanking noises to come from your unit.


For mechanical problems, going the DIY route is not recommended. You will need to take your unit to your maintenance provider, or call a trusted air conditioner repair service to fix the problem. Luce Aircon Services can help you assess the problem and fix it, with follow-up maintenance in order for you to make the most of your unit.

Refrigerant Refill or Leaks

Refrigerant, which is the liquid responsible for absorbing heat away from the room and cooling the air, can leak through small cracks in the AC unit. When the refrigerant leaks, the cooling compressor malfunctions, causing the air conditioner to freeze up and form ice. 


An uncommon fact is that refrigerant does not need frequent refill as it does not evaporate quickly, and is not consumed in the cooling process. The need for frequent refrigerant refills means that the cooling liquid is seeping through a small crack in your unit.


In this case, a licensed technician will be able to find and fix the leak. Fixing the leak can save you the hassles from serious damage, which can be costly and time consuming to remedy.

How to Prevent Frozen Air Conditioners

Besides knowing what to do when your AC unit freezes up, preventing your air conditioner from freezing is important to prolong the quality of your unit. 

Clean Air Filter Regularly

As a cardinal rule, air conditioner filters should be cleaned every two weeks; more frequently when used daily or in a high traffic area. Check the brand of your unit for the manufacturer’s instructions on how to take out the air filter, and whether your model has a washable or a disposable filter.


To clean a washable filter, simply take out the aircon filter and wipe away the grime using a damp cloth. You may also use a dry vacuum cleaner to get rid of loose dirt. Take an old toothbrush or a soft bristle brush, and scour away any remaining dirt with soap and water.


For disposable filters, which need to be changed every 3-6 months, you’ll need to purchase an air filter compatible with your model. Check your manufacturer for filter options, or contact us today for a free consultation.

Keep Supply Vents Open

Good airflow is healthy for both you and your unit. Check your outdoor unit for any blockage, which may be restricting air circulation to your unit. Outdoor vents can get particularly filthy due to their exposure to the elements.


Clear away any items that may be blocking indoor and outdoor vents. Wipe away any dirt or debris to prevent them from entering your AC unit. Keep a scheduled cleaning of both the indoor and outdoor units to prevent blockage of airflow.

Professional Cleaning and Maintenance

An air conditioning unit needs to undergo a routine professional cleaning every 6 months to maintain its good working function. AC components need to be assessed and repaired, if necessary, and a chemical wash can make your unit feel as good as new. 

Ice isn’t Cool

In the summer, an air conditioning unit can make days more bearable, and nights more comfortable. A freezing AC may sound like bliss, but the reality is ice and AC’s do not mix. Clean your AC units regularly, and talk to your maintenance provider for a routine professional cleaning and upkeep to ensure your air conditioner stays in perfect condition.


For more aircon repair and maintenance tips, make sure to check out our blog today.

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Staff Writer

Staff Writer

This article is written by our passionate staff writers who seek to share our knowledge from our business

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