Why do I have a Frozen AC?

By August 14, 2019 April 2nd, 2024 Air Conditioning
frozen air conditioner

Why Do I have a Frozen AC?

One of the most surprising sights a homeowner can experience is seeing a frozen AC unit—air conditioning caked in ice during the heat of summer. If you are wondering why your air conditioner is freezing, our St. Louis air conditioning repair technicians at Design Aire are here to explain the possible causes.

Understanding how your air conditioner works is important because it helps you to make better choices when it comes to replacing parts or buying a new air conditioning unit when the time comes. When it comes to heating and cooling, we believe in working with you to help you make the best decisions for your household. Contact us if you have any questions or if you are in need of HVAC service in St. Louis.

Why is there Ice on my AC?

To understand why your air conditioner is caked in ice, you must first understand a little bit about how your evaporator coil works. Of course, this is a quick overview of only one part of your air conditioning system. Your Design Aire qualified repair technician understands all of the important factors that go into providing you with a comfortable, cool environment. 

Unlike your heating system which forces warm air into your home, your air conditioning unit doesn’t actually “produce” cold air to blow through your vents. It’s more accurate to say that your AC unit takes heat from indoors and transfers it outdoors.

About your AC Evaporator Coil

Among other components, your air conditioning unit has an evaporator coil. The evaporator coil works with the rest of your system to cool your house by removing heat from the inside air.

Air is drawn by the blower from inside your rooms and funneled toward the evaporator coil. At the same time, refrigerant is circulated through the evaporator coil, entering as a liquid through a metering device. The expansion valve releases pressure on the refrigerant and causes it to become very cold as it winds through the coils. The cooled refrigerant absorbs heat from the air   and eventually travels through the rest of your system, where the heat is released into the outside air. 

So Why is my AC Unit Frozen?

When the humidity from your inside air hits the cold evaporator coil, it quickly cools and turns into liquid form—much like dew on balmy summer mornings. This water drips down into a pan and is channeled away from your unit, usually outdoors. This is why running your air conditioner reduces humidity in your home.

In order to function properly, there must be plenty of airflow through your evaporator coil. If air is restricted, heat is not drawn into the coils and their temperature will drop below freezing. Combine that with the water vapor condensing on the outside of the coil, and you get ice—and a frozen unit.

Check the Airflow

The first step in fixing a frozen AC unit is finding out what is restricting your air flow. This could be a number of things, including:

  • A dirty filter
  • Clogged ductwork
  • A dirty evaporator coil
  • Malfunction of the blower motor

A trained Design Aire AC technician can safely check for anything that might be obstructing your airflow to determine if that’s the cause of your frozen air conditioning unit.

Assess the Refrigerant

Another possibility could be that the refrigerant level is low. If the refrigerant is leaking or is at a low level, it will not circulate properly and can cause moisture to collect in one area of the line. It is not uncommon for your coil to develop tiny pinhole leaks resulting from corrosion caused by a mixture of condensation and chemicals commonly found in household air. 

Your Design Aire technician will check the refrigerant level and inspect the line to make sure there are no leaks or other problems. Contact us for quick service.

Turn off the Cool when It’s Cool

If your air conditioner is running even as nighttime temperatures cool down, your unit is at risk of freezing. As outdoor temperatures reach the 60 degree mark, your indoor air may be warm enough to trigger your thermostat, but outdoor temps put the system out of balance. When overnight temperatures go down, try to avoid using your air conditioner whenever possible to avoid potential problems with freezing. 

Contact the Pros at Design Aire

No matter how much your air conditioner operates, it’s important to perform routine AC maintenance to keep your system running efficiently. If something does go wrong, you’ll be better able to troubleshoot the problem. Design Aire can help you avoid problems and keep you cool all summer long. 

When your air conditioning unit freezes, call our trusted St. Louis AC service technicians at Design Aire. We are here for you 8 a.m. to 9 p.m., seven days a week, and we are equipped and ready to help. 

Stay cool. Contact Design Aire.