An AC that freezes up with ice on the coil or refrigerant line is usually caused by restricted airflow from a dirty filter or blocked vents, a dirty evaporator coil, a failing blower fan, or low refrigerant from a leak. Turn the AC off and set the fan to on to thaw the ice, then replace the filter; if it freezes again or you are low on refrigerant, call for same-day AC repair, because running a frozen system can damage the compressor.
Common causes
- Dirty air filter restricting airflow
- Blocked or closed supply/return vents
- Dirty evaporator coil
- Failing blower fan motor
- Low refrigerant from a leak
Steps to try, and when to call us
- Turn the AC off; set the thermostat fan to ON to thaw the ice (can take a few hours).
- Replace a dirty air filter.
- Open all vents and clear returns.
If it freezes again, or refrigerant is low, call First Response. Low refrigerant means a leak that needs a tech, not just a recharge.
Frequently asked questions
Can I run my AC while it's frozen?
No. Turn it off to thaw first. Running a frozen system can damage the compressor, an expensive repair.
Why does it keep freezing after I change the filter?
Then it's likely low refrigerant or a dirty coil/blower. Those need a technician to diagnose and fix.
How fast can you come?
Same day, 24/7 across San Antonio.