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Top 6 Causes of Frozen AC Coils

Frozen Ac Coils

A frozen AC coil is a problem that tops the list of most common issues with an air conditioning system. Unfortunately, every AC owner has faced this issue at least once.

Shortly, we will make this problem a piece of cake for you to solve. You can effortlessly solve this problem if you know the underlying cause.

Keep reading to know all potential causes that can lead to frozen coils.


Take a look at the 5-second summary of all the causes that can potentially lead to frozen AC coils:

  • Leakage of the Refrigerant.
  • The filters Need Cleaning.
  • The Fan is Damaged.
  • Condensing Chamber is Blocked.
  • Thermostat Lost Efficacy.
  • Overload on the AC.

Detection of the cause is the first step toward solving your problem. You will need to identify which of the following causes best suits your situation and then fix it following the method discussed with them:

Causes of Frozen AC Coils

Some signs to identify the frozen coils in time include decreased to no cooling effect produced by the AC, excess condensation, and dripping moisture.

Let’s quickly dive into the causes of frozen AC coils, with the most common cause discussed first:

1. Leakage of the Refrigerant

Air Conditional Refrigerant

Your air conditioning system comes with a fixed amount of refrigerant, the primary component to condition the air.

If there is any leakage of this “cooling chemical,” the longevity of your system will decrease drastically.

Not only will this leakage affect the lifespan of your system, but it will also hinder its performance and causes its coils to get frozen.

The first thing you will need to check after having a freezing airpipe is the refrigerant.

How To Fix It

  • Use ice thaws to remove the ice from the pipes carefully.
  • Locate the leaking point on the pipe or along the whole refrigerant line. Then, fix that point using professional tools and chemicals.
  • You can call a professional AC consultant to fix the leakage for you.

Never try to remove the ice on the frozen coils by yourself manually or using a tool. It can not only crack the coils but can also permanently damage the system.

2. Filters Need Cleaning

Air Cleaning Filter

Next in line, we have dirty filters that could cause ice buildup on the pipes.

Sometimes, the filters become deposited with dirt and debris to the extent that they block the normal flow of the refrigerant.

This blockage causes the refrigerant to remain inside the building-up pressure, eventually leading to condensation in that area, causing ice to form. The ice then freezes the pipes around that area.

How To Fix It

  • Thaw the ice using professional help.
  • Expose the interior of the AC by removing the outer surface.
  • Take the filters out.
  • Thoroughly clean them making them free of all dirt and debris.
  • Replace them with new ones if you have been using them for long.

Professionals suggest that you should change the filters of your air conditioning system at least once every three months to ensure optimum performance.

3. The Fan Is Damaged

Air Conditional Fan

Fan plays a crucial role in air distribution, condensation, and smooth refrigerant flow.

When the fan is acting up, it can impede the normal airflow inside the system leading to unfavorable conditions.

The irregular circulation of the air will affect the evaporation of the air and causes the coils to freeze because of the pressure difference between the inside and the outside of the system.

How To Fix It

You can quickly fix this issue by first thawing the ice followed by professional unblocking of the fans. Next, remove all the debris or dirt stuck inside the system’s fan. After this, restart your system and test.

4. Condensing Chamber Is Blocked

Air Conditional Frozen Chamber

If the condensing area of the AC system gets blocked, the air that goes in that area cannot flow smoothly in the forward direction.

Instead, it will start to build up in that area, and the pressure difference will make the coils freeze around that area.

Your indoor unit will no longer be able to produce any cooling effect because there is no airflow to the indoor unit.

How To Fix It

After thawing the ice, like in previous cases, clean the evaporating coil and put it back on.

Make sure the condensing unit is working properly, and call a technician to check if it’s working properly.

5. Thermostat Lost Efficacy

Air Conditional Thermostat

A thermostat is responsible for manipulating the air and making it cold or hot as per the adjustments of the system. If the thermostat gets out of order, it will not be able to condition the air properly.

This increases the difference in temperature and pressure of the outside and inside air which causes the coil to freeze.

If your room suddenly becomes too cold or too cold as opposed to the temperature you have set, it is a sign that your thermostat is damaged.

How To Fix It

After taking care of the ice, check the thermostat by carefully monitoring the performance of your AC.

If it overworks or underworks, call a technician to fix the thermostat or replace it if it is damaged beyond repair.

6. Overload on the AC

Overload Air Conditioner

During extreme weather conditions, you might set your AC to adjust the inside temperature, which differs significantly from the outside temperature.

This creates a temperature disparity that makes the AC run on maximum power for an extended period.

In these situations, your AC can get overworked and potentially lose its efficacy.

Moreover, the internal machinery will also start to wear down fast, leading to multiple system issues. This system failure can even cause frozen coils.

How To Fix It

  • Besides taking care of the frozen coils by thawing, turn your AC off for several hours and let it cool down. Then, restart it only after a day or two.
  • During extreme weather conditions, avoid setting unrealistic temperature limits on your AC. Instead, choose a suitable temperature that is comparable to the outside temperature.
  • Also, do not leave your system running for hours and hours unattended. Instead, give it breaks and intervals when a long operation is required.


Frozen AC coils top the problems that most AC owners and technicians face.

They can be caused by blockage of coils, damaged fans, dysfunctional thermostats, and an overload of the system.

After taking care of the ice by thawing it, you will also need to solve the cause, so it doesn’t happen again.

Identifying the right cause and using a highly specialized method to treat the cause will enhance the performance and lifespan of your system.

Frequently Asked Questions

Will Frozen AC Fix Itself?

The ice on the coil can melt if you turn off the system for at least 24 hours. But, without treating the underlying cause, there is a high chance that it will appear again.

Can I Keep My Frozen AC Running?

Keeping your AC running when its coils are frozen is not a good idea. It puts your compressor at serious risk of getting damaged permanently.

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