Why Is My AC Covered in Ice?

By admin,

  Filed under: blog

Notice ice on your refrigerant lines? Or see pools of water around the indoor unit of your air conditioner?

Both are signs that your AC is frozen, which can come as quite the surprise in the middle of a warm, Oklahoma summer.

Don’t worry—we’ll help you troubleshoot this common AC problem. 

The reason your AC is freezing is either because:

  1. Insufficient air is blowing over the evaporator coil
  2. Your system has low refrigerant

We’ll explain both of those causes in more detail below. We’ll also explain 3 DIY fixes you can try before calling a pro.

Want a professional to fix your AC right away? Our trained technicians are standing by, ready to help!

Frozen AC cause #1: Low airflow

The indoor unit of your AC system has a component called an evaporator coil. The evaporator coil cools your home’s warm air with the help of refrigerant, a liquid/gas substance that circulates through the coils.

Evaporator coil found in a central AC in Edmond, OK

The evaporator coil in a central AC

If the evaporator coil doesn’t get enough warm air blowing over it, the refrigerant will get too cold, which causes ice to form on the coils. Eventually, the coils can freeze over completely, which prevents your air conditioner from cooling your home at all.

Problems that can cause low airflow over the evaporator coil include:

  • A Dirty air filter
  • A Dirty evaporator coil
  • Closed or blocked vents
  • Blower motor/fan issues
  • Collapsed air ducts

Some of these problems you can try to fix yourself; others require professional expertise. In the last section of the blog, we’ll share some DIY solutions for the problems you can fix.

Frozen AC cause #2: Low refrigerant

Like we mentioned above, your AC uses refrigerant to help cool your home’s air. 

When warm air blows over the evaporator coil, refrigerant absorbs the warmth from the air, then carries it to the outdoor unit where the hot air is dumped into the outside air. 

The refrigerant cycle in a central AC

However, if the refrigerant levels drop, the pressure in your AC drops as well. This change in pressure can cause the refrigerant to get really cold and freeze.

If you have low refrigerant it means there’s a leak somewhere in your system—either in the refrigerant lines, evaporator coil or compressor (which is located in the outdoor unit.)

Since refrigerant is a potentially harmful substance, you’ll need to contact a professional to find the leak and refill your system to the appropriate refrigerant level. 

Now that you know the reasons why your AC is freezing, let’s look at some quick ways you can try and fix the problem.

Before you call a pro, try these 3 DIY fixes

Try the following steps to unfreeze your AC:

  1. Turn the fan setting to ON
  2. Check your air filter
  3. Open all vents

Fix #1: Turn the fan setting to ON

First, go to your thermostat and turn the fan setting to ON. This will help thaw the ice and prevent damage to the compressor. 

Leave the thermostat set to ON until the ice has thawed. Then, switch it back to AUTO.

Note: Turning the fan setting to ON won’t fix the freezing problem permanently, it will just help in the short term while you try the other repairs or call a professional.

Fix #2: Check your air filter

Next, you’ll want to check your air filter. A dirty air filter could be blocking airflow to your evaporator coil, causing your AC to freeze.

If your filter is dirty, replace it with a new one. Then, run your AC as normal and see if it gradually unfreezes and remains unfrozen.

Clean vs dirty air filter

Fix #3: Open all vents

After checking your air filter, you’ll also want to make sure all the vents are open in your house—even in unused rooms.

This will help your AC get proper airflow and should reduce the chances of your AC freezing again. (Remember to keep your vents open all the time to maximize airflow.)

Leave all your air vents open

AC still covered in ice? Let an Edmond technician help

If you’ve tried the DIY fixes above and your AC is still freezing or not cooling your home properly, it’s time to call a professional.
For almost 20 years, we’ve provided first-class AC repairs to Oklahoma residents. We offer 100% satisfaction on all repairs, and our highly-trained technicians will always give you upfront, honest pricing.

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