Ice on the indoor coil or the copper line outside means the system is running too cold. Running it frozen can damage the compressor, so stop and thaw first.
Thaw it safely
- Set the thermostat to Off for cooling and turn the fan to On
- Let it thaw completely — that can take a few hours
- Put towels down; thawing releases a lot of water
- Replace the filter before turning cooling back on
Why coils freeze
- Low airflow: dirty filter, closed or blocked vents, a weak blower
- Low refrigerant: from a leak
- Dirty coil that can’t absorb heat
- Running on cool nights with a low set point
Low refrigerant means a leak
Refrigerant isn’t used up like fuel. If it’s low, there is a leak, and topping it off without finding the leak is a temporary fix.
When to call
If it freezes again after a thaw and a new filter, call. Evaporator coil repair · AC repair · example: frozen coil from a dirty filter in Magna.
Frequently asked questions
How do I unfreeze my AC?
Turn cooling off, run the fan, let the ice melt completely, and replace the filter before restarting.
Why did my AC freeze up?
Usually low airflow from a dirty filter or blocked vents, or low refrigerant from a leak.
Can I keep running a frozen AC?
No. Running it frozen can damage the compressor.