Fixing Frozen Air Conditioner Coils and Other Cooling Problems

Someone using their hand to test the temperature of the air from an AC unit.
  • 1-4 hours
  • Advanced
  • 250-500
What You'll Need
Towel
Hair dryer
Vent filters
Coolant
Coolant installation kit
What You'll Need
Towel
Hair dryer
Vent filters
Coolant
Coolant installation kit

If your air conditioner seems to be losing its cooling ability, the problem may be as simple as frozen or clogged air conditioning coils. Other causes of reduced cooling include restricted air flow and low refrigerant. Even though you may not be experienced in AC service, you can fix all three of these probable causes in several easy steps.

Step 1 - Thaw Frozen Condenser Coils

Find your electrical breaker box and turn off the switch that controls power to your air conditioner, and allow the coils to thaw. Depending on the ambient air temperature around your condenser unit, it could take up to 24 hours for the coils to melt any ice that is plugging them.

Step 2 - Dry the Air Conditioner Coils

Once your condenser has had time to thaw completely, remove any pooled or standing water and use a towel to dry any remaining moisture that may remain on the machinery.

Step 3 - Turn the Air Conditioner's Fan On

After turning the breaker switch on again to restore electricity to your AC, find the thermostat that controls your unit. Set the thermostat control so that only the air conditioner's blower, or fan, is operating. The fan will help melt any ice or frost clogging the coils by circulating air through them.

Step 4 - Heat the Condenser's Coils

You can speed up the thawing process by using a hand-held hair dryer. Be sure when you use this method of heating that you switch the dryer setting to low heat. A heat setting that is too high can crack the condenser's coils.

Step 5 - Check Vent Filters

Vent filters, when clogged with dirt and dust, are likely to reduce air flow and conditioner's ability to cool your house. To maximize cooling efficiency, you will need to check your vent filters. If they are dirty or clogged, replace them with new ones. If you don't have extra filters on hand, you'll find them at most hardware or home improvement stores.

Step 6 - Add Coolant

Another condition that often reduces cooling efficiency is low coolant in your AC unit. The best way to check for low coolant, and add it when necessary, is to buy a coolant installation kit which you can usually find at a nearby home improvement store. Most of these kits will include directions for adding the coolant.

Step 7 - Test the Cooling Capacity

Once you have completed the rest of these steps, test your air conditioner's ability to cool. Turn the thermostat setting to "cool," wait a few minutes, and then test the air coming from the vents. If the air blowing through the vent is as cool as you would like it to be, you can rest assured your repairs were successful.