Fix it
Why is my AC freezing up?
Ice on an air conditioner is never decoration. The evaporator coil is designed to run just above freezing; anything that pushes it colder — less warm air across it, or less refrigerant inside it — turns humidity into an ice block.
What it usually is
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Starved airflow: filter, registers or blower
The coil needs a steady supply of warm room air to stay above freezing. A packed filter, closed registers or a lazy blower motor drop the load and the temperature follows.
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Low refrigerant charge
Less refrigerant means lower pressure and a colder coil. Ice from an undercharge often starts at the coil inlet and creeps along the suction line.
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A dirty coil insulating itself
A film of dust on the fins blocks heat transfer just like a filter would — the coil freezes behind its own grime.
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Running cooling in cool weather
Below about 60°F outside, pressures fall low enough to ice the coil even in a healthy system.
What you can check yourself
Switch cooling off and run FAN only until the ice is gone — hours, not minutes — with towels ready for the melt. Replace the filter, open every register, and look at the coil if accessible: dust mats can be gently brushed once thawed. Then run a test cycle and watch for re-icing.
When it’s a job for a pro
Re-icing on a clean filter and coil means charge diagnosis, and low charge means finding a leak, not just topping up. Repeated freeze-thaw also deserves a look at the drain pan, which absorbs all that meltwater.
Coil cleaning typically runs $150 to $400; leak diagnosis and repair $300 to $1,000. The thaw itself is only patience.
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