You just got home from work on a summer day, and when you pull into the driveway you see a layer of ice on your air conditioning unit. But how can there be ice when it’s so hot outside? There are several reasons why ice can accumulate on your AC in the summer. Here’s what to do if you notice ice building on your AC.

What to do first

When ice forms on the air conditioning unit, the first thing you’ll want to do is go to your thermostat and turn the AC off. Let all of the ice thaw completely, because the longer you leave ice to build up on your unit, the more likely it is for there to be additional damage to your HVAC system. It can even lead to permanent damage! Once the thermostat is set to off, you may want to check air flow and change your filter. In some cases, fixing the air flow can solve the problem. But unfortunately, sometimes there can be a bigger problem causing your unit to ice over.

Reason for the freezing

How can an AC unit in the hot sun get ice buildup? One problem that can cause this is when your HVAC system doesn’t have proper air flow. Restricted air flow can cause the system’s evaporator coil to drop in temperature to below freezing. Combine that with humidity in the air, and you get ice. As ice builds up on the coil, your AC’s cooling ability will become worse and worse. If you suspect a lack of air flow to be the problem, try checking and changing your air filter if it’s dirty; make sure there are no objects or dirt obstructing the airflow, and check the coil to make sure it’s not dirty.

If that doesn’t fix the problem, you may need to watch the weather and turn off the AC when the temperature drops too low. Some air conditioners won’t function well when the outside temperature drops below about 60 degrees Fahrenheit.

Another common reason for ice buildup can be issues with your system like a refrigerant leak. If the refrigerant level is too low, this can cause the pressure to drop in the evaporator coil, which can lead to a moisture freezing on the coil. In some cases, you may need to fix or replace a weak blower motor, which can also cause freezing.

Following up

No matter what the reason is for your AC freezing, taking action is key to minimizing the risk of permanent damage to your HVAC system. Turning off your system to let it begin thawing is the most important step. Next you should try to prevent it from happening again. Contacting an HVAC company is a great way to diagnose any problem with your AC and find a solution. A professional can help find any obstructions, repair refrigerant leaks, and fix or replace faulty blower motors.