Why Is My Air Conditioner Frozen and How Do I Fix It?

Frozen outdoor AC unit.

Is your air conditioner frozen? You’re not alone. It’s common for the components of an air conditioner unit to freeze up, and it’s usually very easy to fix. Occasionally, you’ll need professional assistance, but most likely your frozen AC is caused by an easily remedied problem.

Why do air conditioners freeze up?

To understand why your air conditioning is frozen, you should know how it works.

The inside of your AC unit consists of a compressor, condenser coil, and a fan. Warm air from inside your home is pulled into the refrigerant and absorbed. The refrigerant then is carried to the outdoor coil and goes through the compressor. The compressor then moves the coolant through the entire system. When the refrigerant transfers through the condenser, the fan distributes air to the condenser coil, which completes the cooling process and blows cold, fresh air throughout your home.

So now that you’re an AC expert, let’s figure out how to unfreeze it.

How do you unfreeze an air conditioner?

A frozen air conditioner is usually caused by one of these four issues:

  1. Poor Airflow

If your AC isn’t drawing enough warm air from your home to the inside the unit, there will be nothing to prevent the condensation on the coil from turning into ice. A dirty air filter is usually the main culprit in airflow issues. If changing the filter doesn’t make a difference, inspect your vents and ductwork for visible obstructions.

  1. Low Refrigerant

When your air conditioning is low on refrigerant, the coils become too cold and freeze. The most common cause of low coolant is a leak, which requires a significant repair. If your AC is blowing air but the air isn't cold, you likely have low refrigerant and will need to consult with an HVAC professional.

  1. A Mechanical Issue

A frozen air conditioner could point to a problem with one of its internal components. A broken fan, dirty coils, or many other mechanical issues could be contributing to the freeze. Try turning your system off entirely and allowing it to defrost. If there aren’t any mechanical or cleaning issues that you can see, contact an HVAC professional.

  1. Broken Thermostat

A faulty or broken thermostat is a common cause of a frozen AC. If your unit is only freezing at night, this is a sign that your thermostat isn’t shutting off at the correct temperature, causing the coils to freeze. Try the obvious solution first: Change the batteries. If this doesn’t resolve the issue, contact Aire Serv. You most likely need a new thermostat.

Prevent Frozen AC Units with Regular Maintenance from Aire Serv

One of the best ways to prevent your air conditioner from freezing is to have it regularly serviced by the HVAC professionals at Aire Serv. An experienced local Aire Serv technician can help determine the best course of action to keep your AC in top, unfrozen shape at all times.

Schedule an appointment online or contact the location nearest you to get started.

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