8 minutes read

Help! My Air Conditioner Froze Up

Stephen Jabro


Finding ice covering your air conditioner is an odd sight to see in the middle of a hot southern Missouri summer. But it’s an unfortunate problem that can happen because of a few different issues. A relatively minor issue may have caused the ice, but there are potentially more extensive breakdowns that can also cause an AC to freeze up.

Either way, there are some steps homeowners can and should take to help get their cooling system working again. Jon Wayne Heating & Air are your local AC repair experts. We want to help you have the information you need so you don’t have to face a hot home this summer.

What should you do when your air conditioner has frozen up?

You can start with a few DIY steps. A simple issue may be causing your air conditioner to freeze up, and it might be one you can repair quickly and cheaply!

Air conditioner froze up with ice on AC outdoor unit

The Most Common Causes for a Frozen AC

Keep reading to learn the most likely reasons why ice will develop on an air conditioner. Some of these causes are issues that many homeowners can try to tackle on their own. We’ll list the troubleshooting steps to help resolve minor problems.

Other causes to a frozen AC will be best left to trained HVAC technicians who can accurately diagnose the problem and successfully resolve it.


No matter what has caused your AC to freeze up, there is a basic – yet critical – step you must do first to get your AC starting to thaw out. This step starts at your thermostat.

Turn your thermostat to OFF. Then turn the fan ON.

This will allow your air conditioner to start defrosting. How long will it take for your AC to thaw out? On a hot Missouri summer day, your AC unit might be fully thawed in just a few of hours.

Do not try to speed up the process. While it might be tempting to rush the ice melting, do not try to melt the ice with any additional tools or devices. Do not try to chip the ice away or apply heat sources to your AC unit.


1. Insufficient Air Flow

The most common reason an air conditioner coil freezes up is due to airflow. There is not enough air flowing over the evaporator coils. If not enough air is flowing, the refrigerant gets too cold and might cause the coils to freeze.

Very dirty air filter that caused an AC unit to freeze up with iceThe leading reading why the airflow could be hampered is that your air filter is dirty. A dirty filter can block or clog airflow and is a common cause for an air conditioning unit to freeze up.

While the AC unit is thawing out, check the air filter on your furnace. If it’s dark and dirty, replace it. It is possible you have not been changing out your filter as often as you should. Unfortunately, that’s a mistake that a lot of homeowners make.

Once your air filter is replaced, and the air conditioning unit is fully thawed, try turning the thermostat back to COOL and see if your AC works now.

While you’re at it, take a look at the vents throughout your home. Are they all open? While many people believe you should close any vents don’t need to save energy use, that is a misconception. The ducts in your home were laid out to work as a system. Closing off too many vents can cause a problem with the airflow.

You may be able to close a few vents without causing a problem, but it may lead to a frozen AC unit if you close too many.

Are any vents blocked or covered? Check the vents to make sure the air is not being obstructed. Move away any items (like furniture or curtains) that are blocking the vents.

2. Low Refrigerant Levels

Being low on refrigerant (freon) is another common reason why an air conditioner has frozen up. Low refrigerant often means that there is a leak. This could be a dangerous problem, and it needs to be safely handled by a trained AC technician.

If you suspect a refrigerant leak, contact Jon Wayne Heating & Air right away for a quick repair. We provide 24/7 emergency service in Springfield, Mt Vernon, and the surrounding communities.

Call Jon Wayne Heating & Air for 24/7 emergency repair in Springfield, MO and Mt Vernon, MO

3. Dirty evaporator coils

Dirty evaporator coils are another problem that can cause an air conditioner to freeze.

A significant buildup of dirt or debris on a cooling system’s evaporator coils can prevent it from absorbing the heat it needs to produce cool air. If the air filter is clean and vents are not getting blocked yet you still have poor airflow, it is likely caused by a dirty coil.

Performing annual maintenance on your system should keep this problem from happening. Jon Wayne Heating & Air provides professional AC maintenance and tune-up service. Contact us to have the local pro’s handle your home comfort maintenance needs.

4. Mechanical Failures

A mechanical problem can cause an AC unit to freeze. There are many mechanical components to your home’s cooling system. And many different things could go wrong, such as a kink in a refrigerant line or a broken blower fan. These sorts of issues can change the pressure in your system, making your AC freeze up.

A malfunctioning blower motor is another mechanical problem that can freeze out an air conditioner. It’s the part inside your unit that makes the fan blows return air over the evaporator coils. If an insufficient amount of air moves over the coils, your system will get too cold and could freeze up.

5. Inadequate AC or Ductwork for Size of your Home

There is such a thing as “too big” when it comes to air conditioners. You want the exact right size unit for the size of your home. (You can read more here about why a Bigger AC Isn’t Always Better). A unit that is too big can cause problems, including a frozen AC system.

If you have a relatively new AC system or have had a reconfiguration of your ductwork, or you’ve had any remodeling done to your home, this situation may be more likely for you.

There is a formula for finding out precisely what type and size of AC is needed for each home. Contact us at Jon Wayne, and we will come out and inspect your home to ensure you have the suitable unit you need. Of course, we’ll do that after we fix the frozen air conditioner and get cool air back and flowing through your home.

Jon Wayne Heating & Air AC repair van in Springfield, MO neighborhood


If one of the troubleshooting steps worked and cool air is flowing again, DO NOT STOP READING NOW. You’re not out of the woods yet.

You may have just fixed the problem temporarily. Let your cooling system continue working for a while, and then check to see if ice is forming again anywhere. If it has frozen up again, that means you have not resolved the core problem. And that means you need to have it checked by a professional AC repair technician.

Jon  Wayne Heating & Air is trained and experienced in servicing any type or model of air conditioner or cooling system. We provide 24/7 service to Springfield, Mt Vernon, and the surrounding Missouri towns. Call on us to fix any AC problem!


Call Jon Wayne today at (417) 831-9500 in Springfield and (417) 466-2515 in Mt Vernon.

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With more than 20 years of experience servicing homes and businesses in Springfield, Mt Vernon and surrounding Missouri communities, Jon Wayne Heating & Air is the company you can trust for professional quality service. With 100s of positive reviews, we are the heating and air company relied upon to provide the most efficient and reliable heating and cooling systems to homes across southwest Missouri.


From the S Kansas Expressway, exit on Bennett St. heading west, then turn right on S. Scenic Ave and we’ll be on your right. Coming from W. Sunshine Street, you’ll take S. Scenic Ave going north and we’re just about a mile up the road on your right at 1324 S. Scenic Ave.

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We are conveniently located right off Highway 39 on the northeast part of town. From W. Mt Vernon Blvd (Hwy 265), turn to go north on Hwy 39.
You’ll find us just about a mile up the road by turning left onto
Breckenridge Rd.

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