Why Your AC Freezes Up
When your AC freezes or ices over, the evaporator coil becomes too cold and moisture turns to ice. This blocks airflow, reduces cooling, and can damage the system if not addressed quickly.
Common Causes of AC Freezing Up
1. Dirty air filter
A clogged filter restricts airflow and is the most common cause of frozen coils.
2. Low refrigerant levels
Low refrigerant reduces pressure in the system, causing the coil to drop below freezing.
3. Dirty evaporator coil
Dirt and biofilm on the coil prevent proper heat absorption and can lead to icing.
4. Blower motor issues
If the blower isn’t moving enough air, the coil can freeze.
5. Blocked or closed vents
Closed vents increase static pressure and reduce airflow across the coil.
6. Clogged drain line
Excess moisture can freeze on the coil if drainage is restricted.
How to Fix a Frozen AC
1. Turn the system off
Running the AC while frozen can damage the compressor. Turn it off and let the ice melt completely.
2. Replace the air filter
A clean filter restores airflow and helps prevent future freeze‑ups.
3. Open all vents
Ensure every supply and return vent is fully open and unobstructed.
4. Inspect the blower
If airflow is weak, the blower motor or capacitor may be failing.
When to Call a Professional
Call for service if:
- The coil freezes repeatedly
- You suspect low refrigerant
- The blower is weak or not running
- You see ice forming on the outdoor unit