Can Dirty Coils Cause an AC To Freeze?

An AC unit provides the appropriate cooling power in your indoor controlled climate. But what do you do if, instead of cooling your rooms, your unit freezes? You may have heard rumors about it, but can dirty coils cause an AC to freeze?

The cooling process happens in the coils as refrigerant passes through them, separating hot and cool air. Your unit distributes the cool air through your vents and warm air outdoors, but dirty coils halt this process. Below, our five-star team explains more about this phenomenon and when to start looking for “AC coil cleaning near me.”

Can a Freezing Unit Be a Direct Response To Dirty Coils?

Your unit contains two types of coils. The evaporator coil resides within the indoor evaporator unit, and the refrigerant that travels within it absorbs indoor heat. However, if a layer of particles lines the outer coil surface, it cannot properly absorb the warmer air surrounding it. Therefore, instead of the coolant evaporating and carrying the warm air to the condenser unit for expulsion outdoors, it becomes cooler and freezes within the coil.

After traveling through the evaporator coil, the Freon moves to the outdoor compartment’s condenser coil. The refrigerant should release the warm air. But if there’s no warm air in the system due to a dirty evaporator coil, it halts the heat transfer process within the condenser coil and causes this line and the entire unit to freeze.

Other Causes of Frozen Coils

Now that you know the answer to, “Can dirty coils cause an AC to freeze?” you understand regular coil cleanings are imperative to their optimal functionality. That’s why all expert HVAC teams place this task at the top of their maintenance checklists. With semi-annual services, you never have to worry about internal buildups, but other factors contribute to frozen coils:

Low coolant levels cause a similar effect as a frozen evaporator coil. If you don’t have fully charged Freon levels to absorb ample heat, lower coil temperatures lead to freezing.
Dirty filters bar warm air from entering the unit. Dust and dander buildup on the mesh restricts airflow just as uncleaned vents keep cool air trapped within the system. Limited warmth in your AC unit halts heat transfer and causes your air conditioner to freeze.
A blocked condensate drain line removes moisture from your unit during condensation and leaves stagnant water in your drain pan. If mold and grime fill the drain, it also causes water to flow backward into your evaporator compartment. Since the evaporator coil is the coolest during a cycle, nearby water will freeze, almost instantly forming ice crystals.

Why Should You Remedy Frozen Coils Immediately?

No one wants higher energy bills. After all, that’s one of the many reasons the U.S. Department of Energy encourages you not to run your unit 24/7 or at too low a temperature. However, you may still see your monthly bills rising in costs if you have frozen coils since they slow the heat transfer process.

Slower heat transfer means your unit cycles longer to provide the same cooling power. That means your system pulls more electricity from your energy grid each time it turns on. Not only will your bills rise, leaving you to wonder, “Can dirty coils cause an AC to freeze?” but you’ll also have a bigger carbon footprint alongside the following:

Warmer indoor temperatures or hot and cold spots: If dirty coils stand between the hot air and the refrigerant that is supposed to absorb it, your system won’t evict enough heat from your home. Instead, your HVAC will redistribute the warm air back into your home.
More frequent Servicing: If your system runs longer, each internal component has to work harder to cool your home. Overworking these parts causes premature deterioration and breakdowns that require more frequent and costly repairs.
Diminished unit lifespan: Each time your unit needs a repair, it struggles to keep up with your cooling demands. Therefore, the more AC repairs your system needs, the less efficient it becomes over time. You’ll need a unit replacement early on.

Our Experts Are the Epitome of Cool!

Can dirty coils cause an AC to freeze? While sometimes it takes a dirty evaporator coil to freeze your system, other times it’s backed up water or blocked airflow. If you’re unsure what’s causing a frozen air conditioner, contact our number-one team at Cool By Design Air Conditioning Experts with over 100 five-star reviews at 954.541.8277, and we’ll provide an air conditioner repair today!