No one likes being in an overly hot house. In mild heat, you’re uncomfortable, and in extreme heat, you’re vulnerable to heat stroke. Unfortunately, you’re not likely to know that your AC unit has a problem until it’s time to turn it on. You want to find the problem and get it fixed as fast as possible.

There are a number of potential reasons why your AC unit isn’t working as well as you’d like. Below, we list some AC unit troubleshooting tips for the most common issues.

1) Check the Air Filter

Your AC’s air filter can become clogged with dust and debris with time. That debris restricts the airflow, which can cause problems for your unit and make it less effective. We generally recommend checking the air filters on all your HVAC systems, including your AC unit, once a month as part of your routine HVAC maintenance.

Your AC’s air filter is likely near the system’s thermostat or air handler, which is the large metal box that stores the fan and motor. To check the filter, you can remove it and hold it up to the light. If the air filter is visibly dirty, you should replace it.

2) Check the Thermostat

ac unit troubleshooting

Sometimes the problem is in the thermostat, not the AC system. If the temperature reading on the thermostat seems off, that might be the source of your problem. You might also have the thermostat set for heating instead of cooling. It’s easy for thermostat heating and cooling schedules to get wonky after a power outage or an accidental button press.

Try resetting your thermostat and replacing the batteries — you’d be surprised how often that fixes AC problems. Different thermostat models come with different reset methods, so check your owner’s manual on how to reset yours.

Dust and dirt inside the thermostat can also cause problems, so you can also try cleaning the thermostat interior. You may need to take the thermostat off of the wall or unscrew the anchor screws to remove the cover. From there, you can use a vacuum hose, soft brush, or cloth to get the thermostat interior clean.

3) See If the Condenser Coil Is Dirty

The condenser is the AC component that sits outside the house. It has a coil that releases heat from your home into the outdoors. The condenser coil is essential to your AC’s function, and it needs regular maintenance.

If your condenser coil looks dirty, you can clean it with a garden hose. Start by aiming the water upward into the coil’s top to get rid of the crud buildup, then aim it down to flush the debris out. You can shoot water directly into the coil, with pressure no stronger than the shower setting on a garden nozzle.

While you’re there, you can also take a look to see if there is shrubbery interfering with your condenser unit. Your condenser needs plenty of space, so we recommend keeping all plants at least a foot away from your unit.

4) Check the Evaporator Coils

The evaporator coil is the part of your AC that removes heat and moisture from your indoor air. This part of the system is typically inside your home or garage. Sometimes the evaporator coil can freeze, which results in little cooling and higher utility bills.

If your evaporator coil has frozen, you’ll likely see a lot of condensate drainage near your indoor AC unit. There may be frost or ice on the copper refrigerant lines coming from the evaporator coil cabinet, or even on the exterior refrigerant tubing or outdoor unit.

Don’t try to fix a frozen evaporator coil yourself. If you think a frozen coil is your problem, you should call a professional AC technician to help.

5) Call a Professional Who Has Experience in AC Unit Troubleshooting

Most other air conditioning problems should be diagnosed and fixed by a professional. Some problems are hard to find — and dangerous to fix — without proper training and equipment.

Paragon can help you troubleshoot your AC. We serve homeowners throughout East King and Snohomish Counties in Washington. If you’re having problems with your AC, give us a call.