An air conditioner should never build ice during normal operation. Ice means the evaporator coil is getting too cold, which usually comes from low airflow or low refrigerant.
The important part: do not keep running the AC while it is frozen. It will not cool properly, it can leak water indoors as it thaws, and it can stress the compressor.
Check these first
What you can safely check before calling
Turn cooling off
Set the thermostat from Cool to Off. If the indoor blower works, set Fan to On to help melt the ice faster.
Change the filter
A clogged filter is the easiest fix. If the filter is packed with dust, the coil may have been starved for air.
Open vents and returns
Make sure supply vents and return grilles are open and not blocked by furniture, rugs, or storage.
Wait before restarting
The system needs to thaw fully before a real diagnosis. Restarting too early can hide the problem and make the ice come right back.
Likely repair causes
What usually needs a technician
Refrigerant leak
Low refrigerant lowers coil temperature. The right fix is to find the leak, repair it, and recharge to manufacturer spec.
Dirty evaporator coil
Dust on the indoor coil blocks heat transfer and can cause ice even with a clean filter.
Weak blower motor
If the indoor blower is slow or failing, the coil can freeze because not enough warm air is moving across it.
Restricted ductwork
Collapsed flex duct, blocked returns, or poor duct design can create chronic freezing on otherwise healthy equipment.
Call if you see this
When to stop troubleshooting and schedule service
- Ice comes back after a clean filter and full thaw.
- The copper refrigerant line is frosted outside.
- Water is leaking around the indoor unit.
- The blower runs but airflow from vents is weak.
Next step
