Why Is My Air Handler Freezing Up Inside?

Q: What causes an air handler coil to freeze inside the unit?

A: Air handler freeze-ups happen when the evaporator coil becomes too cold. This is almost always caused by low airflow or low refrigerant. Once ice forms, cooling stops completely and the system should be shut off until thawed.

1. Low Airflow (Most Common)

Anything that slows airflow across the coil can cause freezing:

Dirty air filter
Clogged coil
Blower motor failure
Collapsed ductwork

Start by replacing the filter. If the system still freezes, airflow is restricted elsewhere.

2. Low Refrigerant

If the refrigerant charge is low, the coil gets too cold and begins developing ice. This is usually caused by a leak.

A leak check is required — freeze-ups will keep repeating otherwise.

3. Closed or Blocked Vents

Closing too many supply vents or furniture blocking vents reduces airflow and contributes to freezing.

4. Thermostat Set Too Low

Running the AC at very low temps (66° or lower) in humid weather can trigger coil freeze-ups.

What to Do Right Away

Turn the system OFF at the thermostat
Set fan to ON to help thaw the coil
Place towels under the air handler if thawing indoors

When to Call Beacon

If the coil freezes again after thawing — or if you hear hissing, bubbling, or see ice forming on the suction line — call Beacon’s friendly technicians in the yellow polo shirt.

We’ll see how Beacon can help.

Content Update & Editorial Review

This article was reviewed and updated on February 1, 2026 by Chris to improve clarity, confirm troubleshooting accuracy, and align with current safety guidance.

📍 Contact Beacon Services & Appliances
📞 (352) 726-7530
🌐 www.BeaconSaves.com