Why Did My AC Unit Freeze? Causes and Solutions for Frozen AC Coils

Have you noticed that your air conditioner isn’t working? Maybe you’ve spotted some ice on the unit. Neither are pleasant discoveries, and it is quite possible that the cause of the problem is that your evaporator coils are frozen. There are many reasons your coils can freeze up, and fortunately, nearly all of them are easily resolved. When your coils freeze over, the licensed and insured HVAC technicians at Total Air & Heat can inspect your system and perform the tasks and repairs required to restore your air conditioner to operation.

Contact Total Air & Heat to schedule air conditioner service.

How AC Coils Work

Your air conditioner has two sets of coils. The air handler, located indoors, contains the evaporator coil, designed to absorb heat from inside the home. Refrigerant within the coil absorbs this heat as it flows through the metal fins of the coil, and in the process transforms from a liquid to a gaseous state.

As the gas passes through the coil, it flows to the condenser unit outside the home. As it does this, the gas reverts to a liquid state and releases heat and humidity through the metal fins of the coil. It’s a simple, efficient process that repeats itself as often as necessary to achieve the interior temperature set by your thermostat.   

Causes of a Frozen AC Unit

• Poor airflow: Blocked vents or dirty air filters can diminish the amount of air flowing over the coils. This can cause the refrigerant within the evaporator to get too cold, condense, and freeze over.
• Damaged blower fan/motor: A damaged or malfunctioning blower motor or fan can reduce airflow over the condenser coil, causing it to freeze over.
• Low-refrigerant: If your system has a leak, it will reduce the amount of refrigerant within it. The loss of pressure will prevent the coils from properly cooling because it allows the refrigerant to absorb too much heat, which then causes it to freeze as it moves through the system.
• Dirty coils: Dirt, grime, sludge, and debris on the coils can impede the transfer of heat from the coil and into the atmosphere. 
• Thermostat problems: A malfunctioning thermostat can cause your AC unit to operate well into the evening or early morning. As outside temperatures fall, it reduces heat transfer which can cause the evaporator to freeze over.   

What To Do When Your AC Unit Freezes 

There are several steps you can take when your AC unit freezes over, including:

1. Turn the AC unit off and allow it to thaw. This may take around a day depending on the outside temperature and weather.
2. Inspect the air filters. If they’re dirty, replace them.
3. Turn on the fan using the fan-only setting. 
4. If the coil is still frozen, you can try using a hair dryer set to a low or medium heat setting; avoid the temptation to use a high setting, as you may crack the coil.
5. Wipe away any moisture and allow the unit to completely dry.
6. Once dry, clean the coils.

Preventing Frozen AC Coils in the Future

There are a few things you can do to prevent your coils from freezing in the future, including:

1. Stay on top of preventative maintenance schedules.
2. Regularly change air filters.
3. Periodically clean the evaporator and condenser coils.
4. Regularly test and adjust your thermostat.
5. Keep as many supply registers open as possible.

When to Call Total Air for Professional for AC Repair

At Total Air & Heat, our licensed and insured HVAC technicians know the frustrations a malfunctioning air conditioner can create. When your cooling system fails, we will thoroughly inspect the unit to determine the cause of the malfunction and promptly perform the required air conditioner repairs. Since 1957, our teams have proudly served the community and we guarantee your satisfaction with the services and top-quality solutions we provide.

When you need fast and reliable AC service in Texas, contact Total Air & Heat to schedule a service appointment today.