AC frozen or iced up?

What usually causes this

These are the common possibilities, not a diagnosis. A page cannot tell which one it is — that takes a technician testing the system.

Dirty filter or blocked return

The most common cause. Without enough warm air moving across it, the coil drops below freezing and moisture on it turns to ice.

Low refrigerant charge

A leak lowers the pressure in the coil, which lowers its temperature. The system freezes, cools poorly, and the leak keeps going.

Dirty evaporator coil

Dust and film on the indoor coil act like a blanket and restrict airflow through it.

Blower problem

A failing blower motor, a dirty blower wheel, or the wrong fan speed setting moves too little air.

Running in cool weather

Running the AC hard on cool nights, well below its design conditions, can occasionally let the coil ice up.

What you can safely check yourself

• Turn cooling off at the thermostat and set the fan to On. The moving air helps the ice melt. Expect this to take several hours.
• Replace the air filter if it's dirty.
• Make sure every return grille and supply vent is open.
• Put towels down near the indoor unit — melting ice produces a lot of water, and the drain pan can overflow.
• Once fully thawed, turn cooling back on. If ice returns within a day or two, the cause isn't just the filter.

What we check when we get there

1. 1The technician checks airflow first — filter, coil, blower and static pressure — since that's the most common cause.
2. 2If airflow is fine, refrigerant pressures and temperatures show whether the charge is low. A low charge leads to leak detection.
3. 3The condensate drain is checked too, because a thawing coil puts a lot of water through it.

What it is likely to cost

If a dirty filter was the only cause, there may be no repair at all. Coil cleaning, blower work or a refrigerant leak cost progressively more. You get the price before work begins.

Diagnostic / service call

$89

Heavy coil cleaning

From $299

Blower wheel pull & clean

From $329

Leak detection

From $249

Leak repair + recharge

$499–$1,299

Blower motor

$549–$1,099

Prices are starting points for standard work in the Savannah area. Final price depends on the system and site, and is confirmed before work begins. Permits and code-required upgrades may be additional.

Repair or replace?

A leak in the indoor or outdoor coil on an older system is one of the situations where replacement is worth pricing alongside the repair, especially if the system uses R-22.

Questions people ask about this

How long does a frozen AC take to thaw?

Often several hours, sometimes most of a day, depending on how much ice has built up. Running the fan on its own speeds it up.

Is a frozen AC an emergency?

Usually not, as long as you switch cooling off. It becomes urgent if water is overflowing into the house or the outdoor unit is struggling loudly.

Why does my AC keep freezing after I changed the filter?

Then the filter wasn't the whole story. A low charge from a leak, a dirty coil or a weak blower are the usual next suspects, and all need a technician.

Where to go next