AC Evaporator Coil Freezing Up

Nothing’s better than stepping into a nice cool house after a long hot day in the summer sun, right? However, if you notice that the house doesn’t seem quite as cool as it should, you may have an AC evaporator coil freezing up. This problem can prevent the unit from cooling your home to a comfortable temperature. What’s worse, if left untreated, a frozen AC evaporator coil could potentially cause an entire system failure.

If you suspect an AC evaporator coil freezing up is your issue, you may be wondering what an evaporator coil is. This coil is housed within the indoor unit of your air conditioner. It holds the refrigerant that is responsible for cooling the air.

The air conditioner dehumidifies the air in your home, resulting in condensation on the AC evaporator coil. This is typically not an issue, as the water drips off the coil into the drain pan and all is well. However, if there is a problem with your unit, the condensation freezes to the coil, causing your home not to feel as cool as you’d like.

In this image, you can see the oh-so-frozen AC evaporator coil.

Causes of AC Evaporator Coil Freezing Up

Condensation on the AC evaporator coil freezes if there is not enough return air passing over the coil or if that air isn’t warm enough. So now that we know why the ice is there, what is causing the inadequate air flow or air temperature?

#1 – Dirty AC Evaporator Coil

The evaporator coil itself can collect dirt, dust, and other buildup if the air filter is not cleaned properly. This layer of debris blocks the coil from absorbing heat from the return air. Thus, when condensation forms, it cools so much that you now have an ac evaporator coil freezing up.

Lesson: Keep your air filter clean and clear of dirt and dust!

#2 – Insufficient Air Flow

The frozen AC evaporator coil can also be caused by insufficient return air flow. As detailed above, a lack of warm air blowing over the coil causes freezing. So what would cause too little air to blow over the coil?

• Clogged air filter
• Air register blockage
• Leaking ducts

Lesson: Clear any blockages that will restrict air flow!

#3 – Refrigerant Leak

The refrigerant contained in the evaporator coil is responsible for absorbing heat from the air. This warm absorption heats the coil, which in turn keeps the condensation warm enough to drip off. If there is a refrigerant leak, levels will be too low to collect enough heat to warm the coil. And, you guessed it, the condensation freezes on the evaporator coil.

Lesson: Monitor your AC unit for leaks!

A great way to prevent your AC evaporator coil from freezing up is to have it tuned every year. You can have a professional tune your air conditioner to keep it in tip-top shape. You should also be familiar with what your AC needs to stay healthy.

If you need help with your AC Compressor, contact our specialists here.