What To Do When Your AC Unit Freezes Up

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What To Do When Your AC Unit Freezes Up

It can be frustrating and annoying when the temperature outside is 100 degrees and your AC keeps freezing up. We rely on our air conditioning systems to keep us cool, but it is not ideal when they get so cold they grow ice crystals.

Ductless AC unit with front open to show ice on coils

How Does An Air Conditioner Freeze?

When the temperature of air is hot, its molecules are very active. When the molecules are static, the air temperature is cool. Thanks to the Joule-Thomson Effect we understand that as air inside our AC units drop, the molecules slow – but once compressed, they become active again and heat up.

The purpose of an air conditioning unit is to expand its coolant to produce cool air as it leaves the system. So when something is amiss, the whole process is disrupted and the coolant slows down too quickly, causing ice to form.

What Causes An AC To Freeze Up?

The most common culprit of a frozen AC unit is a dirty air filter. Clogged filters restrict air flow, and cause a disruption in the cooling process. Other reasons can include refrigerant leaks, kinked lines, or blockages elsewhere in the AC system.

Small dog sitting in front of fan, yellow wall in background

What Should I Do When My AC Freezes?

If the unit is still running but not blowing cold air, turn the compressor off but leave the fan on. This will help circulate warm air through the unit and defrost it faster. If the unit is not working at all, turn everything off and check the air filter. If the filter is dirty, clean or replace it and let the unit continue to thaw.

Depending on how much ice is there, the defrosting process may only take an hour or two. In more severe cases you should let it rest overnight. Be sure to watch for dripping water as the ice melts and empty drain pan as necessary.

Remember to call the pros at Lancaster Plumbing & Heating for all your AC repair and maintenance needs. It’s better to have small problems addressed now before they become larger ones.

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