Why do air conditioners freeze up? If it happens to you, turn it off. Otherwise, you can damage the compressor, resulting in costly repairs. Once all ice is melted, it’s safe to use the air conditioner, which should start right back cooling things down. The unit may be frozen if it seems to run OK except for very little or no cold air. Look for a few common issues with frozen air conditioners:

Check for proper drainage. The water could be leaking back into the unit causing rust and a humid home. Some units drain outside and some drain inside. In both cases, the water drainage should be obvious. If not, try vacuuming out the drain hose. Every time your A/C cycles, it produces water, especially on humid days. If the water can’t drain properly, the unit will sometimes freeze. Regular checks on the drainage are a good idea, particularly in hot weather.

Make sure the A/C filter is clean. This is the advice that contractors most often repeat, yet dirty filters are the main cause of loss of efficiency in A/C units.

Check the fan to make sure it’s blowing while the unit is on. If so, the fan speed could be too low and mismatched to the size of the A/C. A certified contractor can determine if this is the case.

Consider your A/C usage to discover why yours might be freezing up. With slightly cooler overnight temperatures, the A/C may be frozen in the morning. If so, the thermostat could be faulty.

Check the airflow around your home. Closing air vents and registers to try to direct cool air to other parts of the house restricts flow and increases the likelihood of frozen coils. It’s the warm air from your house that keeps the coils from freezing – it should circulate as much as possible.

Get the refrigerant level checked by a professional. Too little refrigerant can also explain why do air conditioners freeze up.

For more expert advice and more answers to the question, Why do air conditioners freeze up?, contact Bill Joplin’s Air Conditioning & Heating. We’ve been serving the Frisco, Allen and McKinney areas for more than 30 years.