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Troubleshooting for Frozen AC Coils

Is your HVAC malfunctioning? Among the most common causes for AC malfunctioning, frozen AC coil is definitely at the top. You might not be aware of this, but your HVAC coils might freeze any time of the year, not just during winter. If you notice a layer of ice or frost in your indoor AC system, you have got to fix it ASAP. However, it is not always easy to diagnose if your AC coil is frozen, sometimes it can be quite tricky. Here is all you need to know about frozen AC coils with the causes, signs, and troubleshooting steps for you to follow! 


Causes for frozen AC coils: 

AC coils can freeze any season of the year. Lack of airflow is a common cause for it. If your ductwork is jammed or your air filters are blocked, then the resulting weak airflow hinders the coil’s operation. That’s how the AC coil starts to freeze as the temperatures drop. 

Another alarming cause can be leaks in the unit. If your HVAC system leaks due to mechanical failure, then condensation can pool around the coil that can become frosty over time if the liquid is not drained properly. Later, the ice insulates the AC coil and prevents the heat transfer that causes cooling. 


3 Signs of frozen AC coil:

  1. If you notice that the room is not cooling properly even when the AC is running, it is time to check whether the coil is frozen or not. 
  2. Check indoor or outdoor coils of your cooling system. If you see visible ice, you have got to act immediately. 
  3. You can check the handler to observe condensation or moisture as the frozen coil can cause cooling around the area. 


Troubleshooting for frozen AC coils

  • Change your AC air filter. The clogged air filter hinders air movement. You should change the filter to allow unrestricted airflow from your cooling system. Typically, the accumulated dirt and contaminants hinder the airflow that causes your cooling coil to get frozen. You can often check your filters to maintain better airflow from time to time. 
  • One of the easy DIY steps for air conditioners is to turn off the thermostat and switch on the fan. This can ensure air movement across the indoor coil and may unfreeze the coil. However, it might take more than 2 or 3 hours for it to unfreeze, so you have to be patient. But in the case of denser frost formation in the coil, this is not an effective solution. 
  • If you happen to use your heat pump system, you can run it on the defrost mode to melt the ice on your coils. In air conditioners, you can try to thaw the ice by following the deicing steps. 


Calling for immediate fixing of your frozen air conditioner coils: 

You might be able to solve the freezing problem of your AC coils by following the aforementioned DIY solutions. However, there might potentially be other problems that require HVAC experts. In that case, you should contact HVAC professionals for the proper functioning of your AC coils. 

Cleaning filters: Over time, the dirty filters may prevent proper heat exchange, which eventually causes the coils to freeze. HVAC professionals can thoroughly clean the filters for you. It can ensure prolonged smooth functioning of your AC by preventing frozen coils. 

Repairing ducts: If your ductwork is damaged, it prevents airflow through your HVAC system. Call for HVAC contractors to repair or replace any faulty ducts to prevent the coils from freezing. 

Unclogging drains: The moisture in your cooling system due to a clogged condensate drain pan or line can cause coil freezing. It is ideal for the technicians to clean and unclog the drain pan of the condenser to prevent moisture in your HVAC system. 



It might be hard to inspect the coil freezing problem in your cooling system. However, we hope you can figure out how to handle the issue of your HVAC system with the help of this article. For a quick and easy solution, call for professional help to ensure whether your AC is in the proper condition or not. 


See the summary of this article here in an infographic – 3 Things to Do to Fix a Frozen Air Conditioner Coil [Infographic]

3 Things to Do to Fix a Frozen Air Conditioner Coil