Signs of frost include visible ice crystals on the unit and/or warm air blowing out of the unit. If you leave your AC unit running when it’s frosty, the problem can get worse and your unit could require costly repairs to fix. If the breaker that controls your AC system also controls other things that you don’t want to turn off, it’s okay to leave the breaker on. Turning it off is just an extra precaution. In the meantime, use fans or a portable AC unit to keep your home cool if you can’t bear the heat.
Check the AC unit’s coils to make sure that there are no visible ice coils on them before proceeding. If you want to speed up the melting process, blast the unit with warm air from a blow dryer on the LOW setting only. Don’t pour hot water onto an AC unit to try and melt the frost. It is an electrical system and can get damaged this way.
Accumulations of moisture are what freeze when you run your AC at cold temperatures for long periods of time, so that’s why it’s important to soak up all the excess moisture before you use the system again.
If the problem of your AC unit frosting over repeats itself, try some of the techniques from the frost prevention method below to see if they solve the problem.
Dirty air filters cause the system’s coils to get dirty, which can lead to freezing. If the filter is very dirty, it’s best to just replace it.
When the coils get dirty, they get too cold and moisture that accumulates on them freezes over. You could spray off the coils with a hose or use condenser cleaning acid. If you use acid, wear protective gear like goggles and gloves and mix the acid with water according to the instructions on the package.
If you notice that the drain line is clogged, pour 1/4 cup (59 mL) of distilled white vinegar into the T-shaped access pipe on the drain line. Wait 30 minutes, then flush the drain line out with water to clear clogs. Alternatively, use a CO2 gun and AC drain brush to clear the clogs.
An HVAC technician will also be able to inspect your system for refrigerant leaks and repair them if they find any.
When you’re asleep, run the AC at 82 °F (28 °C) to save energy. When you’re away, don’t set it any lower than 85 °F (29 °C).
