AC Freezing Up? Why It Happens and What to Do
Ice on an air conditioner is a symptom. Something is restricting airflow or lowering coil temperature too far.
Common causes
Restricted airflow
A dirty filter, blocked return, closed vents or a dirty coil reduce the air moving across the coil.
Low refrigerant
A leak lowers pressure and drops coil temperature below freezing.
Blower problems
A weak blower motor or failed capacitor reduces airflow.
Very humid conditions plus a system problem
Humidity increases the load on the coil and makes freezing more likely when anything else is off.
What you can safely check
- Turn the AC off and set the fan to On to help the ice melt.
- Replace the filter.
- Make sure vents are open.
- Do not chip at the ice.
When to call a professional. Call a technician if the system freezes again after thawing, you see water leaking as the ice melts, or you suspect a refrigerant leak. Never open electrical panels or remove access covers on equipment. If you smell burning or see smoke, turn off power and call 911 if there is any danger.
How long does it take for ice to melt?
It can take several hours. Running the fan with the cooling off helps.
Is it okay to keep running a frozen AC?
No. It can damage the compressor and cause water damage when the ice melts.
Why did my AC freeze in summer?
In humid weather a restricted airflow or low refrigerant condition quickly causes ice.
Next steps and related help
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