What Do You Do When Your Air Conditioner Freezes Up?

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What Do You Do When Your Air Conditioner Freezes Up

It might seem counterintuitive, but did you know that an AC unit is most likely to freeze up during the summer? This is when you are most likely going to be running it. Before we get into how to fix that chunk of ice, let’s first learn more about the most common reasons for an air conditioner freezing, with the help of Total HVAC Houston, which services HVAC in Houston.

Your air conditioner turning into a block of ice during the summer months isn’t a result of a spell being put on it by a mage, but rather a breakdown of something basic. The most common reasons an air conditioner freezes up is because of bad air flow, broken refrigeration, or the outside air.

What Causes Air Conditioner Freeze Ups?

Your HVAC system is working hard to reduce the temperature, and when the air flow is restricted, humidity that it collects can create a build up around the evaporator coil. Small bits of ice crystals start to form, which causes a snowballing effect eventually causing total blockage. There are a few things you can do to prevent air flow restrictions in the first place. Replacing air filters is probably your best bet, as an inundation of dust and other particulates can create a wall. Collapsed, obstructed, undersized, or damaged ducts are also a major cause of air flow restriction.

A refrigerant leak can cause a pressure drop inside of the evaporator coil. This drop in pressure creates a vacuum that has to be filled, typically by moisture-ridden cold air. This humidity accumulates and eventually starts to freeze.

Low temperatures outside can also cause freezing; this is nothing surprising. But did you know that it doesn’t take below freezing temperatures to create ice? Below 60 degrees Fahrenheit, an air conditioner won’t operate properly and can potentially freeze up.

My AC Is Already a Small Iceberg, What Should I Do?

If you are already in the position that your AC is frozen, don’t despair, as there are still a few things you can do. First step is to unthaw your air conditioner and the second is to avoid it happening again.

You’re going to need to turn your AC off at the source, i.e., the electrical breaker. Typically you’ll need to wait a day for the ice to completely thaw. You can also keep the AC part of the HVAC system turned off and just run the fan to circulate warm air through faster.

To prevent it from freezing up again, you need to remove the moisture from the coils. Once the ice is melted, turn the system back on, but only the blower or fan. Just letting the air hit the coils without activating them can cause the water to evaporate, and the system should operate like normal from here.

What Do I Need to Do to Prevent Future AC Issues?

Proper maintenance is required for all AC units and you would be foolish to skip it. This means changing out air filters regularly, cleaning evaporator coils, checking the coolant levels, and scheduling an annual tune-up by a professional.

How frequently you change your air filter depends on the type of air filter and what is going on in your house. Most manufacturers recommend 30 to 60 days, but you can wait longer if you don’t have any pets, kids, or allergies. If there are allergies or pets in your home, the number can be as low as 20 to 45 days.

Fiberglass are the most common and disposable air filter, and there are also pleated filters which are considered more effective but more expensive. There are also more exotic varieties like electrostatic, HEPA, and UV filters to work with.

Dirty coils, as mentioned before, can cause freezing but also reduce the effectiveness of your cooling inside your home. Wiping them down with a non-abrasive rag will work well, along with removing any dirt, dust, or foliage in the nearby vicinity.

An average HVAC system is expected to last upwards of 10 to 15 years, while properly maintained ones can last well over 20 years. Doing any of the above things can ensure you’ll get the most out of your AC unit for years to come.


A freezing AC unit is a pain that usually has a simple solution: just turning the unit off and waiting. Recurring problems with your unit can be a result of poor air circulation, low or leaking refrigeration from the coils, or running the AC in less than 60 degree temperatures.

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