Power Issue

A quick fix for an air conditioner that’s not cooling is an issue with the power source. Check the breaker box or fuse box to ensure everything is working correctly. If you trip a breaker or blow a fuse, your AC can't run. Some units also have an on-off switch near them. Make sure this is set to the On position.

Thermostat Problems

Another easy fix is an issue with the thermostat, which acts as the brain of your AC unit. Make sure it's set to “cool,” and the thermostat setting is lower than the temperature in the house. Your AC only runs when the thermostat senses a room temperature that's higher than your setting. Sometimes, the settings can get changed accidentally.

If your settings are correct, make sure the thermostat is working correctly. Some thermostats are battery-powered, so you might need fresh batteries. If the thermostat still doesn't turn on, it might need to be replaced.

Clogged AC Drain Line

Your AC unit collects condensation, which drains out of the unit. If this drain gets clogged, the AC unit has a safety feature that shuts it down and won't let it run until you clear the clog. You can use a wet-dry vacuum to suction debris that's blocking the drain.

Most air conditioners have an access point near the unit with a cap on it and a pipe leading outside where it drains. If you can see the clog from either point, you can manually remove it. Pouring some vinegar down the drain can help clear the clog, or use your wet-dry vacuum to help remove it.

Frozen Coils

The coils inside the AC unit can freeze if you don't maintain the unit well. One common cause of this is a clogged air filter, which prevents proper airflow. Ice develops on the coils and decreases the cooling capacity. You might notice warmer air coming out of your vents, and your home won't likely reach the temperature setting on the thermostat.

When this happens, you need to change your filter and let the ice melt. Turn off your AC and shut off the power to it. Then, wait until the ice melts. Turn the unit back on and check it regularly to make sure it doesn't freeze again. If it keeps freezing after you change the filter, you might need a professional to diagnose the issue.

Motor Failure

Older units could experience a motor failure. You might notice unusual sounds in the motor before this happens. If the motor fails, the unit won't run at all. Replacing the motor is something a professional should handle.

Low Refrigerant

If your system is working correctly, you won't ever have to add refrigerant. However, a leak in the system can cause the refrigerant levels to drop and keeps the unit from cooling properly. Refrigerant leaks should always be handled by a professional. Refrigerant is dangerous if you don't know how to handle it, and the levels need to be precise for the system to work correctly. The leak also needs to be repaired to prevent additional refrigerant loss.

Troubleshooting an AC Not Cooling

If your AC isn't working, start with the easiest solutions first. Following these steps can help you figure out the issue:

• Make sure the power source is working, the thermostat is functional and the temperature setting is appropriate.
• Look for a reset button on your AC, or shut off the power for 5 to 10 minutes and restart it to do a manual reset.
• Listen for sounds that might indicate if some parts of the unit are running. Make note of any strange noises you hear.
• Shut off the power and pop the cover off the unit to look inside for signs of an issue, such as ice.
• Clean the AC drain line to remove clogs.

If these steps don't reveal an easy fix, it's time to call an HVAC professional to inspect and repair the unit. It's best to leave any work inside the unit to a professional. Working with the moving parts of the machine can be dangerous if you don't know what you're doing, and completing the work correctly is essential to make sure the machine operates safely.