At the very height of the summer season, the sight of an air conditioning unit entombed in ice can be an odd one. Thanks to the way the refrigeration process works, it's possible for frost to form on the AC coils as your AC system works to keep your home cool. Under normal operation, the surface temperatures on the AC system's coils can dip slightly below freezing from time to time, allowing a light coating of frost to form.

Restricted air flow caused by obstructions and low refrigerant levels can cause coil temperatures to drop even further, resulting in heavy frost and ice buildup. The following shows what you can do if your AC freezes up during operation.

Give Your AC a Time-Out

Before you do anything else, you'll need to shut down your AC system and give it time to thaw out. It usually takes an hour or two for a frozen AC system to completely thaw, in most cases. Make sure to have a mop or a wet/dry shop vacuum on hand to remove standing water as the unit thaws out.

You should never attempt to physically remove ice from an AC unit. Using an ice pick or any other sharp instrument can damage the AC system beyond repair.

Check for Air Flow Issues

AC units often experience excessive frost or ice buildup due to an air flow blockage somewhere in the system. As you inspect your AC system, consider these common causes along with corrective measures for each issue:

• A dirty air filter can block air from entering the AC system. Replace it with a brand-new filter and make sure to keep up with scheduled air filter changes.
• The evaporator and condenser coils can collect dirt, dust, and other debris over time. You can either clean the coil yourself or have a professional do it for you.
• Broken duct segments and dirty ductwork can also cause air flow restrictions. Carefully check your ducts and have them cleaned by an AC service as needed.

Have a Pro Check the Refrigerant

Running your AC system on low refrigerant can eventually lead to a frozen unit. Your AC system doesn't consume refrigerant, but it can lose refrigerant due to minor leaks within the refrigerant lines or a component handling refrigerant.

If you suspect low refrigerant levels, have your HVAC technician perform a thorough AC system inspection. Your technician will measure current refrigerant levels, check for any leaks throughout the system, and charge the refrigerant according to your AC manufacturer's specifications.