Why Is My Air Conditioner’s Refrigerant Line Covered in Ice?

27. November 2021 | Air Conditioner

Even in the hottest temperatures, ice can build upon or inside the refrigerant line of your air conditioner. But this is not a good sign at all. If you notice any such thing in your AC, you know there’s a big problem in the making. These type of AC issues needs to be fixed quickly before it breaks down the entire system.

Now the question is why is my air conditioner’s refrigerant line covered in ice? Well, this can be caused due to various reasons. It happens when something causes the evaporator coil to get too cold. It can also occur when the heat is stopped from transferring from your house to the Freon. If you are want to know more about this issue and how to fix it, you should give this article a read.

What causes the problem?

How to fix the problem

Ice build-up in the refrigerant line can occur due to various reasons. To fix the issue, you first need to know what’s causing the problem. Some of the main reasons why your refrigerant line is frozen could be:

  • Low refrigerant level

Low refrigerant levels often mean you have a leakage in the refrigerant line. This causes the Freon to expand excessively in the evaporator coil of the unit. As a result, the temperature drops below the freezing limit, and it causes ice to form. In this case, you should call a qualified technician to check the issue and repair it. To prevent this from happening, you should get your air conditioner checked regularly.

  • Restricted airflow

Proper airflow is very crucial for your unit. It allows it to function normally. In the case of restricted airflow, the temperature drops and causes the unit to freeze up. This can happen due to closed vents, dirty air filters, leaks, or clogs in the ductwork. Depending on what’s limiting the airflow, you may have to replace your air filter, repair your air ducts or clean your ductwork.

  • Dirty evaporator coil

A dirty evaporator coil restricts proper airflow through the system. This can cause ice to form on your unit. This can also cause your unit to consume energy while reducing the cooling effect. If ignored for long, this could damage the compressor of your unit completely. You should shut off the unit until you clean the coil or replace it with a professional to prevent this from happening. You should also clean the evaporator coil regularly. 

  • Outside temperature is too low

In case you didn’t know, air conditioners are not designed to be used below 62 degrees Fahrenheit. If you live in a region where the temperatures are extremely low, this could be common. In this case, you need to switch off the unit and allow it to thaw. To prevent this from happening, turn off the unit at night.

  • Mechanical failure

You can get frozen refrigerant lines due to mechanical failure as well. It can be caused by a damaged fan motor, blower fan, broken valves, blocked drain, or kinked refrigerant lines. All this can lead to a frozen unit pipe. For this, you should call a licensed HVAC professional to inspect the issue and repair it. However, this could be prevented with regular maintenance of your unit.

Problems You Can Fix

If you notice ice build-up in the refrigerant line of your unit, you can do two things. You can either fix it at home or call a professional. However, this depends on the problem that’s causing it. Some of the issues can be repaired at home, but you may need to call a technician for others.

To help you out, we have shared some of the solutions to try at home:

  • Clogged or dirty air filter

If a clogged air filter is the problem, you should either clean it or change it. A clogged filter reduces airflow over the evaporator coil, which causes ice to build up. This is why you should check the condition of the filter once every month.

  • Closed supply vents

You should not close supply vents, not even in unused rooms. When you close the vents, it reduces the airflow over the evaporator coil. This can cause ice to build up in your unit.

  • Blocked return vents

Make sure that nothing is blocking the return vents. If you get blocked return vents, it will restrict the airflow through the system. This will eventually lead ice to form in the AC. You need to keep a check on these things.

Problems A Professional Needs To Fix


You already know the problems you can fix at home. But some issues need professional help. These are mostly internal issues. To give you an idea, we have laid down the details below.

  • Refrigerant leak

A refrigerant leak can lower the refrigerant level in your unit. This could lead to a lot of problems. In this case, you need a technician to evacuate the remaining refrigerant liquid and then fix the leak. This is a complex repairing task that can be handled better by professionals.

  • Dirty evaporator coil

If the ice build-up is caused because a dirty or clogged evaporator coil, you should get a technician to fix it. Since this is an internal issue, you better call a professional to handle it.

  • Malfunctioning indoor blower

If you have a faulty indoor blower, it may reduce the air blowing over the evaporator coil. This can cause ice to build up in the refrigerant line. Instead of wasting time, you should hire a qualified technician to fix it.


Various factors can cause a frozen refrigerant line in an air conditioner. It mainly happens when the evaporator coil cools down below-freezing temperatures. If you notice ice-build in your unit, you should call a technician quickly. Ignoring this kind of issue can break down your entire air conditioner.

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