Air Conditioner Freeze Ups: Why Do They Happen And What Can You Do About It?


An air conditioner freeze up occurs when ice forms on the coils while the unit is running. If left unattended, an air conditioner can shut off or suffer serious damage during a freeze up. There are multiple conditions that can cause your air conditioner to freeze. Knowing the causes and how to address the problem if it occurs could save you major money on repairs and air conditioning replacements. Learn why air conditioners freeze, and what you can do to prevent it to keep you from sweating it out in the heat this summer.

Blocked airflow

Lack of air flowing through your air conditioner can cause the temperature of your AC’s coils to drop below freezing. The warm air normally moving through your return ducts passes over your cold refrigerant coils and loses heat in the process. As much as the coil works to cool the air, the warm air works to thaw the coil. When that warm air isn’t present (whether because of small ducts or blocked air filters) the coils cool down and moisture in the air will freeze the coil. Regularly changing the filter should be enough to avoid a frozen air conditioner.

Leaking refrigerant

In order to keep your HVAC system running correctly, the amount of refrigerant inside needs to be balanced. If you are low on refrigerant, it is possible that there is a leak in your line. If you suspect a leak, don’t add more refrigerant until you’ve contacted an HVAC specialist to inspect. Adding more refrigerant to a leaky line will compound an existing problem.

Other possible problems

When the temperature drops below 60 degrees in the summer (generally at night) your air conditioner can suffer. Rather than run the air conditioner during the cool night hours, turn it off to keep it in working order (and save some money.) Other causes of possible freezing could be anything from a faulty thermostat to a slow or broken blower fan. You should consult with a professional if you suspect either of these issues are occurring with your air conditioner.

So, what do you do if your air conditioner is frozen? The first thing you need to do if you suspect your AC is frozen is turn it off. Allow it to defrost and prevent any further damage to the system. No matter the cause, keeping your air conditioner running while you trouble shoot the problem can cause further damage.

Check all your air filters and your refrigerant levels to determine if either are the cause of your problems. If you have dirty air filters, replace or clean them and trouble shoot your air conditioner from there. If your refrigerant is low, call a professional before adding more. No matter what the cause, a professional should be able to fix your air conditioner, or replace it if serious damage has occurred.

Avoid a freeze-up this summer, and keep your air conditioning repair bills to a minimum with a system that is well-maintained.


Contact Climate Control Experts Today!

    • Please enter your name.
    • This isn't a valid phone number.
    • Please enter your email address.
      This isn't a valid email address.
    • Please make a selection.
    • Please enter a message.
Put Us On Your Side