When a customer calls us with air conditioner problems, one of the first things we check is the evaporator coil. This essential part of the air conditioner is supposed to be cold, but when it’s frozen, it’s broken. Most unusually, you might find that only half of this coil is affected by this problem. We’ll answer why half of your evaporator coil is freezing up and what kind of solution you should expect from your HVAC professional. Some HVAC technicians will use the wrong methods to correct this particular problem, so it’s especially important that you know what’s going on when half of your evaporator coil is freezing.

How Does the Evaporator Coil Work?

The evaporator coil of your air conditioner has the job of absorbing the heat inside of your home and releasing it outside. The evaporator coil is full of some kind of refrigerant.Refrigerants are special substances that are very efficient at absorbing and releasing heat when they change from a liquid to a gas and back again. So, when your evaporator coil freezes, it can no longer effectively do its job of moving heat and your air conditioner either doesn’t work or is very inefficient.

Dirty Evaporator Coil

The first potential cause of half of an evaporator coil freezing is that half is dirty. When there is dirt, dust, or other debris on the coil, it can no longer effectively absorb or release heat. Therefore, it tends to freeze over. The solution to this one is simply to clean the coil and make sure you’re getting it cleaned regularly as part of your yearly maintenance.

Poor Airflow in the Air Conditioner

Air conditioners rely on proper airflow to function properly. When there isn’t proper airflow, the refrigerant may not be able to absorb enough heat from your home. Not only will this significantly reduce the efficiency of the air conditioner, but it can also cause some or all of the evaporator coil to freeze over, simply because there isn’t enough heat in it. The solution to this problem is all about finding and fixing the cause of poor airflow, whether it’s a dirty filter or a broken fan.

Refrigerant Leaks

If your evaporator coil does not have enough refrigerant in it, it may not absorb enough heat, which can cause the coil to freeze over entirely. While some HVAC technicians will simply refill the refrigerant, that’s not enough. Refrigerant does not wear out, and if your air conditioner doesn’t have enough of it, it’s because you have a leak. In order to really fix the problem, we have to fix and fix the leak, then refill the refrigerant. If not, you’ll just end up losing more refrigerant, and your evaporator coil will refreeze again.

What Will Happen to My Half-Frozen Coil?

Half-frozen evaporator coils will soon become completely frozen, rendering the air conditioner inoperable. Therefore, it’s important that you get a professional to fix your half-frozen coil before it gets worse.