Why Is My AC Freezing Up?
Ice on your refrigerant lines or indoor coil comes down to two things: not enough airflow across the coil, or not enough…
Ice on your refrigerant lines or indoor coil comes down to two things: not enough airflow across the coil, or not enough refrigerant in the system. Either way, turn the system off now — running it iced up is how a moderate repair becomes a compressor replacement.
Do this first
1. Switch cooling OFF at the thermostat.
2. Set the fan to ON. Blowing room air over the coil thaws it far faster than leaving everything off.
3. Wait. A fully iced coil can take two to four hours. Don't chip at it — you will puncture the coil, and that is a much bigger repair.
4. Put towels down. All that ice becomes water.
The airflow causes (cheaper)
- Clogged filter — by far the most common, and free to fix
- Blocked return vents — furniture or rugs over them
- Dirty evaporator coil — insulates the coil so it can't transfer heat
- Failing blower motor — not moving enough air
- Collapsed or leaking ductwork
The refrigerant cause (costlier)
Low refrigerant drops the pressure in the coil, which drops its temperature below freezing. Moisture in the air then freezes onto it.
The important part: refrigerant is not consumed. If you're low, there is a leak. Anyone who tops it up without finding the leak is selling you the same repair again next summer.
If it re-freezes after thawing
Then it's not the filter. At that point it's a coil, blower, duct or refrigerant problem and needs proper diagnosis — continuing to run and thaw it in a loop is the most expensive option.
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