As summer temperatures rise, your air conditioning system becomes your best friend, keeping your home cool and comfortable. However, one common issue many homeowners face is a freezing AC unit. Understanding why this happens can help you prevent it and ensure your AC runs smoothly all season long. Here are the top reasons your AC system freezes and how to address them.

Insufficient Airflow

One of the most common reasons your AC system freezes is insufficient airflow. Your air conditioner needs a steady stream of air to keep the coils warm and prevent freezing. Blocked or dirty filters, closed vents, or a malfunctioning blower can restrict airflow, causing the evaporator coil to freeze. 

Having too many registers closed around your home can also create air flow issues for your system. A good rule of thumb is to close only 1 register per every 1,000 sqft. 

Closing too many registers PREVENTS your system from cooling your home efficiently. If there’s a vent in your home office that blows right on your face, close that one up and open the one in your guest room. You can mix it up as long as you don’t close too many. 

Solution: Regularly check and replace your air filters. Ensure that vents are open and unobstructed. Schedule routine maintenance to keep the blower and other components in good working order.

Low Refrigerant Levels

Refrigerant is crucial for the cooling process. When the refrigerant level is low, it can cause the pressure in the system to drop, leading to a drop in temperature. This can cause the evaporator coil to freeze over. Low refrigerant levels are usually a sign of a leak, which should be addressed promptly.

Solution: If you suspect low refrigerant levels, contact a professional HVAC technician to inspect your system for leaks and recharge the refrigerant. To fix a low refrigerant issue our techs can conduct a leak search, repair the leak, and recharge your system with the proper amount of Freon to get you properly cooling again.

Thermostat Issues

A malfunctioning thermostat can cause your AC unit to run constantly, even when it’s not needed. This can lead to an overworked system and eventually cause the evaporator coil to freeze.

Solution: Check your thermostat settings and replace the batteries if necessary. If the problem persists, you may need to replace the thermostat or have it professionally calibrated.

Dirty Coils and Filters

reasons your ac system freezes

The evaporator and condenser coils can accumulate dirt and debris over time, reducing their efficiency. Dirty coils can’t effectively absorb or release heat, leading to freezing issues.

Poor airflow is a big reason why your coil will start to freeze up. If you have a dirty filter, air will be restricted from moving over the evaporator coil and through your home. To stay ahead of issues, make sure you’re regularly changing your furnace filter. If you have a 1″ filter you will need to change it more often.

Solution: Schedule regular maintenance to have your coils cleaned by a professional. This will help maintain optimal performance and prevent freezing.

* Add a reoccurring event in your calendar to alert you every few months.

* Buy a 3pk of filters, so you have one hand to change as needed.

Fan Problems

The fan in your AC system is responsible for circulating air over the evaporator coil. If the fan isn’t working correctly, it can lead to poor airflow and freezing.

Solution: If you notice that the fan isn’t running or is making unusual noises, it’s time to call a professional to inspect and repair the fan.

Blocked Condensate Line

The condensate line removes moisture from the evaporator coil. If this line becomes clogged, it can cause water to back up and freeze on the coil.

Solution: Regularly inspect and clean the condensate line to ensure it’s clear of any obstructions. This is another task that can be included in your regular maintenance schedule.

Preventive Measures

To keep your AC system running efficiently and prevent freezing issues, follow these preventive measures:

Regular Maintenance: Schedule annual maintenance with a professional HVAC technician to inspect, clean, and tune up your system.

Change Filters: Replace air filters every 1-3 months, depending on usage and the type of filter.

Monitor System Performance: Pay attention to how your system is running. If you notice any changes in performance, address them promptly.

If you do notice ice on your unit, turn your system off!

 In order to clearly diagnose the issue, we’ll need your unit to be defrosted. Be sure to turn your system off. Feel free to contact Authority Heating & Cooling for any HVAC needs or to schedule your next maintenance appointment. Stay cool and comfortable all summer long!