The main job of your home air conditioner is to remove heat from the indoor air and transfer it outdoors. This ensures that your home’s interior is nice and cool, keeping you cozy even on the hottest of days. But sometimes, air conditioners can freeze up. While you might not think that this is too much of a problem, a frozen air conditioner is not only ineffective at cooling your home, but it can also cause serious damage to the unit. This, of course, can end up being expensive to fix, so knowing why they freeze up in the first place can help you tackle the issue before it is too late.

That being said, there are several reasons why your air conditioner might freeze up. The most common causes of that include dirty air filters, low refrigerant levels, blocked airflow, faulty evaporator coils, and cold outdoor temperatures.

Let’s take a closer look at each of these causes:

1. Dirty Air Filter

One of the most common reasons for an air conditioner to freeze up is a dirty air filter. The air filter helps to remove contaminants from the air, but if it becomes too dirty, it can restrict airflow. Restricted airflow can cause the evaporator coil to become too cold, which can cause the air conditioner to freeze up.

2. Low Refrigerant Level

Refrigerant is a key component of your air conditioner. It helps to remove heat from the indoor air and transfer it outdoors. If the refrigerant level is too low, it can cause the air conditioner to freeze up because, without it, the machine cannot regulate its own temperature.

3. Blocked Air Flow

Another common cause of an air conditioner freezing up is blocked airflow. The air conditioner needs a steady flow of air in order to operate properly. If the airflow is restricted, it can cause the air conditioner to freeze up.

4. Faulty Evaporator Coil

The evaporator coil is responsible for removing heat from the indoor air. If the coil becomes frozen, it’ll no longer function, and this can cause the rest of the air conditioner to also freeze up.

5. Outdoor Temperature Is Too Low

One final reason why your air conditioner might freeze up is if the outdoor temperature is too low. For instance, if the temperature outside is below 60 degrees Fahrenheit, it can cause the air conditioner to freeze up.


As you can see, there are so many reasons your air conditioner can freeze up. Some you can definitely tackle, such as dirty filters, while others you cannot, such as the outside temperature. Regardless, if your air conditioner has frozen up, it’s important to thaw it out as soon as possible. Once the ice has melted, you can check for any of the above causes and take steps to prevent the air conditioner from freezing up again. Also, be sure to reach out to professionals and come inspect your AC if you keep finding it freezing. That way, they can identify the root cause of the issue and get it fixed for you.

Duct Doctor Birmingham is an expert in air duct cleaning. If you are in need of HVAC duct cleaning to keep your system in great shape, reach out to us today!