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Is Your AC Freezing Up? Common Causes & How to Fix

Is Your AC Freezing Up? Common Causes & How to Fix

Despite the humid and hot summer weather, your AC freezing up is one of the most common reasons it stops working correctly. When you have a frozen AC, the coils freeze, which means the unit can’t pump cool air into your home to keep you comfortable.

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To solve this problem, we’ll touch on the biggest causes of a frozen AC unit, what symptoms hint that you have a problem, and what you can do to get your system back up and running. Some solutions are simple enough to tackle independently, but if you try them and your AC keeps freezing, it’s time to call the professionals for help. 

Causes of a Frozen AC Evaporator Coil 

Poor airflow is the root cause of many air conditioner freezes because your unit runs on the Joule-Thomson Effect. This effect draws hot airflow into the warm refrigerant gas that expands and cools. If something interrupts your AC’s warm airflow and causes it to not blow through the evaporator coil where the heat traditionally transfers, it can throw your system out of whack. This causes a frozen evaporator coil or a frozen AC line. 

Clogged Air Filters 

Air filters play a significant role in ensuring your AC runs efficiently. When the filters get clogged with pet hair, dust, or other debris, it restricts airflow to the evaporator coil. A reduced airflow prevents the coil from absorbing heat, and this causes the temperature to drop. When the coil’s temperature goes below the freezing point, the moisture in the air can cause the coil to freeze, leading to ice buildup. 

Low Refrigerant Levels

Refrigerant is a liquid that has the ability to absorb any heat and release it as it goes through your AC. When you don’t have enough, the system pressure inside drops, and the evaporator coil’s temperature can dip below freezing. This can cause the moisture that condenses in the coil to freeze and ice over the evaporator. 

Clogged AC Drain Lines

The evaporator coil removes humidity from the indoor air, causing condensation. The AC drain lines are responsible for draining the condensation from the unit, but the lines can get clogged with mold, algae, or debris. When the water can’t drain, it backs up and freezes on the coil, affecting your AC’s performance and causing water damage when it melts and overflows. 

Damaged Blower Fan

The blower fan pushes the air over the evaporator coil and circulates the cooled air throughout your home. If the blower fan malfunctions or gets damaged, it might not circulate the air properly, or it can stop working. Without enough airflow over the evaporator coil, it can’t absorb heat efficiently, causing the temperature to drop. If it drops too low, you’ll have a frozen AC unit.

Steps to Fix a Frozen AC Unit

A frozen AC is a common problem for many homeowners, especially in summer. As inconvenient as it might seem, acting fast can prevent further damage and ensure your comfort.

1.) Turn Your HVAC Unit Off

The first thing you do to address your AC freezing up is turn it off. Trying to run a frozen unit can worsen the issues and damage parts of the AC. It also protects the compressor from potential damage due to trying to make it overwork in a frozen state. You want to give your system ample time to thaw naturally, which can take several hours. 

2.) Switch Your Thermostat Fan to On 

While the unit is off, switch your thermostat’s fan on. This will help to circulate the air across the frozen coil, making it thaw faster. Also, continuous airflow helps with the drying process of any remaining moisture in the evaporator coil. By turning this fan on, you’ll get a more efficient thawing process and moisture reduction, reducing the risk of mildew or mold growth. 

3.) Check Your AC for Water Damage 

As the unit defrosts, the melting ice can produce a lot of water. If you don’t manage it, it can damage the AC and cause water damage in your home. Check around the unit for pooling water, especially near any electrical connections. If the drain pan under the evaporator coil overflows, this means the condensate drain line has a clog. Address any water damage immediately to prevent mold growth and structure damage. Bring in a professional if you have extensive water damage or repeated freezing. 

Turn Thermostat Fan OnHow To Prevent A Frozen AC Unit 

An AC running at peak performance is critical for keeping your home cool, especially during the hot summer. However, a frozen AC can cause disruptions. Prevention is always better, so taking the following steps can reduce the likelihood of problems with your AC freezing up. 

Clean or Replace Your Air Filter

A leading factor leading to a frozen AC unit is restricted airflow, usually due to an air filter that is dirty or clogged. Air filters trap dust, dirt, and pet dander, preventing them from circulating in your home. These particles can slowly obstruct the airflow, and this can cause the evaporator coil to dip below freezing. Regularly cleaning or replacing your air filters allows for excellent airflow, and you should do so once every one to three months, depending on use. 

Schedule Routine AC Maintenance 

Regular AC maintenance significantly affects the unit’s functioning and longevity. By scheduling routine maintenance with professionals, they can quickly catch and address potential problems. Maintenance generally involves:

  • Cleaning the condenser and evaporator coils
  • Checking refrigerant levels
  • Inspecting the electrical components
  • Ensuring your system is in top shape

Ensure Proper Installation

The correct AC installation is critical for an efficient and effective operation. Poor airflow, wrongly-sized units, and incorrect refrigerant charge can cause inconsistent temperatures and a frozen evaporator coil. Addressing these issues with proper installation and maintenance can significantly reduce the risk of freezing. If you want to install a new system or you suspect your current system isn’t set up correctly, talking with a professional is essential to keep your unit running as long as possible. 

Air Conditioning Maintenance & Installation Services 

When it comes to your AC freezing up, you need expert services. The Elite Heating & Air team are professionals with decades of combined experience in the HVAC industry. Our comprehensive service range ensures that your AC units get flawlessly installed and stay in peak condition with our maintenance programs. Our dedication to excellence ensures every customer receives optimal cooling and indoor comfort, even on the hottest days. Schedule online with our EZ book system if you’re having issues with your frozen AC unit, you don’t think it’s running as it should be, or it’s time for a routine maintenance check.