Why is My Air Conditioner Freezing Up?

For most homeowners, one of the more bizarre sights is a frozen air conditioning unit on a hot summer afternoon. When your air conditioner freezes up, its efficiency is significantly affected. Apart from underperforming, the ice buildup could cause irreparable damage to your entire cooling system. This is one of the reasons why your AC may not be working. So, what causes air conditioning units to freeze up? And, more importantly, what should Mississauga homeowners do when this happens? 

Clogged or dirty air filters 

Air conditioners achieve a cooling effect by circulating your home’s internal air through the cooled evaporator coil. Air filters are placed on vents to keep out dust, debris and other contaminants from getting into the air conditioner. If these filters get clogged, sufficient airflow to the evaporator coil is not achieved. This disrupted heat transfer process results in much lower internal temperatures, leading to ice buildup throughout the system. After some time, the freezing can be observed in the external components as well. Blocking the return vents, which usually happens due to improper furniture placement, will also disrupt the airflow, leading to your air conditioner freezing up. Replace your filters regularly, at least once every three months, to keep them from getting clogged. Be sure to check out our “ultimate filter buying guide” to ensure you get the right filter for your furnace.

Low refrigerant levels 

The refrigerant liquid in AC systems is what facilitates the heat transfer process that cools your home. Air conditioning units are designed to work effectively with a certain volume of refrigerant liquid. If the refrigerant levels drop significantly, then your AC system cannot function optimally. The reduced internal pressure also leads to a temperature drop which causes the system to freeze up. Low refrigerant levels can only be caused by leaks due to damaged coils or refrigerant piping. This is a job that is best handled by professionals, especially when dealing with refrigerants that are classified as controlled substances like Freon.    

Setting the thermostat too low 

A majority of homeowners don’t know their AC unit’s minimum temperature levels. For most models, this is approximately 19.5 degrees Celsius (67 degrees Fahrenheit). When the thermostat is set to extremely low levels for extended periods, you might see ice building up alongside its internal components. The best way to avoid this is to save the lowest temperature settings for extreme cases such as heatwaves. Overburdening the AC unit with extreme settings on a regular basis also leads to a faster rate when it comes to wear and tear.  

Malfunctioning blower fan 

The blower fan’s function is to blow the cooled air from the AC back into the room. This is vital to ensure that proper airflow is maintained to facilitate the heat transfer process. As we saw with the clogged air filter issue, without adequate airflow to the evaporator coil, the AC system cools down to unhealthy levels. This is also observed when the blower fan either stops working or operates at suboptimal levels. Blower fan issues are usually caused by a malfunctioning motor or problems with the control board that powers the motor. If your AC refuses to turn on, the problem might be a blower fan malfunction. If your blower fan is making noise, professional assistance from an air conditioning technician is required to properly diagnose and fix issues relating to the blower fan.

Blocked Drainage System 

During the heat transfer process, as the AC’s evaporator coil cools the room’s air, any moisture in the air condenses and collects in the AC’s drip tray. There is an internal drainage system that expels this water from the air conditioner. If there is a blockage to this drainage system, water will build up and overflow to other internal AC components. This water speeds up the freezing process, potentially causing damage to your AC system. Ensure that the drainage system is free from debris or leakage by scheduling regular maintenance visits by professional technicians.  

Why use Evam Canada?

Our qualified, and experienced, technicians deliver quality workmanship consistently. Our local presence means Mississauga homeowners can rely on us for emergency ac repair visits or regularly scheduled maintenance check-ups.