Why Your AC Unit is Freezing Up: Causes & What to Do

ac cooling pipes frozen during the summer

Wondering why your AC unit is freezing up in the hottest months of the year? You might ask yourself, “How is it that it’s 90 degrees outside and my AC unit has frost buildup?” This issue actually happens to be a very common problem and can lead to further HVAC complications. So, why is your AC unit freezing up? And, what can you do to prevent this from happening? It’s important to understand the causes and preventive measures to tackle this common AC issue. 

6 Common Causes of Your AC Freezing Up

  1. Low AC Refrigerant

Your AC unit requires a certain amount of refrigerant to guarantee the best cooling performance. When the refrigerant falls under the required amount, the balance will be thrown off and lead to your air conditioner freezing.

If you spot frozen coils, this is a common sign your air conditioner has low refrigerant levels. Contact a professional technician to restore your air conditioner’s refrigerant levels and mitigate the possibility of future AC problems.

  1. Dirty Air Filters 

One of the most common factors that leads to your AC freezing up is a dirty air filter. Your air conditioner’s air filter can become dirty due to debris buildup and dirt accumulation. This will then lead to a lack of airflow into your AC system and cause it to overwork itself, resulting in a freeze. Monitor your air filters and change them regularly to avoid a frozen AC unit.

  1. Broken or Clogged Coils

A broken or clogged evaporator coil can also lead to a frozen AC unit. Evaporator coils may become clogged due to dirt and dust buildup or they can become corroded over time and break and lack efficiency. These issues compound and lead to unusual temperatures, leading to ice buildup. 

  1. Blocked Air Vents

A blocked air vent is caused by the same debris and dirt buildup seen with dirty air filters. The same cause leads to the result, a frozen AC unit. Check your air vents regularly and clean and vacuum them when necessary. 

  1. Damaged Blower Motor

The blower motor in your air conditioning system plays a key role in keeping your home cool. If the blower motor becomes damaged or fails altogether, this can cause your AC unit to freeze and cease working. Hearing a rattling sound while it’s trying to operate indicates something is wrong with it. Issues with a blower motor are a more complex issue and an HVAC technician should be consulted if the blower motor is the culprit. 

  1. Clogged Condensate Drain Line

Your AC’s condensate drain line is responsible for removing water created in the cooling system and disposing it away from your home. The condensate drain line can become clogged due to dirt, mold, or debris and the created excess moisture can flow into your AC unit and home, possibly causing issues to both. And ultimately, freeze your air conditioning coils. 

How to Stop Your Air Conditioner From Freezing Up

Now that the causes of this problem have been established, what are the ways to prevent a frozen AC unit? Use these tips as an added layer of protection against freeze buildup. 

Check Refrigerant Levels

Have an HVAC technician inspect your refrigerant levels to determine if your AC unit needs or is sufficient for the time being. 

Replace Your Air Filter

You should practice regularly checking your AC’s air filters. Inspect the air conditioner’s air filters for debris or dirt buildup and clean or replace them every one to two months. This will improve your air conditioner’s performance and the quality of air. Replacing a dirty or clogged air filter can lower your air conditioner’s energy consumption by 5% to 15%. 

Inspect the AC Drain Line

It’s important to check your AC drain line throughout the summer, but using a dry/wet shop vacuum to remove debris and other buildup will help you prevent a frozen AC unit. You can also turn to an HVAC specialist to help with this preventive measure. 

Keep Vents Open

Keeping your vents open and free of blockages is one of the easiest ways to prevent a frozen AC unit. Avoid closing more than two or three vents at any given time.

Contact an HVAC Technician to Inspect Your Fan  

Your blower motor’s fan is a vital piece of equipment to help generate airflow. This is often difficult to do on your own, so contact an HVAC technician to inspect your fan. Keeping the blower motor’s fan in working order is an important step to prevent a frozen AC unit.

Chapman storefront

Local Air Conditioning Maintenance & Repair with Chapman

A frozen AC unit at your home can stem from a variety of causes, but thankfully, there’s a great list of preventative measures to help you start preventing it from happening. If your options have run out and you’re stuck with a frozen AC unit in the Indianapolis, Indiana, area, Chapman Heating, Air Conditioning & Plumbing is ready to help. 
Chapman Heating, Air Conditioning & Plumbing provides reliable, efficient, and local air conditioning services for homes in Indianapolis, Carmel, Fishers, Lawrence, and other surrounding areas. Chapman’s HVAC technicians are there to keep your household cool all summer long.