Something is wrong4 min readSeptember 15, 2026
Why your AC freezes up in North Texas humidity, and what to do first
Ice on your AC means the coil is getting too cold, almost always from low airflow (a dirty filter, a failing blower, closed vents) or low refrigerant from a leak. Turn the system off, set the fan to On to melt the ice, change the filter, and call. Running it iced can damage the compressor.
The two causes
The indoor coil is designed to run just above freezing. Anything that keeps it from absorbing enough heat pushes it below that line, and North Texas humidity provides plenty of water to freeze. Restricted airflow and low refrigerant account for nearly every case.
- Airflow: a clogged filter, a blower motor losing speed, closed or blocked registers, a collapsed return duct
- Refrigerant: a leak has dropped the charge, and the coil pressure falls until it freezes
Do this first
Switch the thermostat to Off and the fan to On. The blower will melt the ice in an hour or two; put towels around the indoor unit because the drain pan can overflow as it thaws. Replace the filter while you wait. If the system freezes again after a clean filter, it is a service call, and it is usually a leak.
Why a good technician will not just add refrigerant
Refrigerant does not get used up. If a system is low, it leaked, and topping it off without finding the leak buys a few weeks at the price of a repair. The right sequence is a leak search, a written price for the fix, and then a proper charge measured with gauges, not a guess from a can.
Questions on this
Can I chip the ice off to speed things up?
No. The fins on the coil bend with almost no pressure and a bent coil restricts airflow for the rest of its life. Fan on, system off, and patience.
It only freezes at night. Why?
Cooler nights lower the coil pressure further, so a system that is marginal on airflow or charge crosses the freezing line after dark first. The cause is the same; the night just reveals it earlier.