How to Maintain Your Air Conditioner

By Amanda Lutz Updated February 6, 2024

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If your HVAC system or air conditioner unit blows warm air, makes unusual sounds, or leaks, it may mean it’s time for a tune-up. Below, we’ll guide you through how to properly maintain your air conditioner with do-it-yourself (DIY) methods, clean individual components of your system, and determine when it’s time to call the professionals.

1. Turn Off the Power and Clear All Debris

The first step in cleaning your air conditioner is to turn off the power, switch off the circuit breaker, and unplug the air conditioner. You can also disconnect your condenser unit, which should have a 240-volt disconnect box.

Next, give your system time to cool down. If you touch your unit while it’s still warm, you could experience an electric shock.

Start clearing debris once the unit has cooled down. Open the outdoor unit and clean the condenser’s floor with a wet/dry vacuum or by hand. Clear leaves and other debris from the condenser fins, which are the thin, metal slats on the outdoor unit.

2. Clean and Replace Your AC Filters

The average homeowner or renter needs to replace AC filters every 90 days, but you should replace filters more frequently if you live in a dry climate, have allergies or a respiratory condition, or own pets.

Take the following steps to clean your AC filter:

  1. Remove the filter from the unit.
  2. Use a dry cloth or wet/dry vacuum to remove any dust or debris.
  3. Scrub the filter with a diluted detergent of one teaspoon of soap to one liter of water. You can also soak the filter in a basin or large sink with a diluted detergent for an hour.
  4. Wash off the soap with a garden hose.
  5. Allow the filter to dry completely before putting it back into the HVAC.

3. Check and Clean the Evaporator and Condenser Coils

Your central air conditioner’s evaporator and condenser coils work together to create cool air, and both must remain clean for the system to function properly.

Check each coil once a year for dust and other debris. You can find the evaporator coil in the indoor system near the air handler or furnace, and you can find the condenser on the outside unit. Clean the coils using a soft bristle brush, AC solvent, or mild detergent, and allow them to dry completely before putting them back into the unit. Cleaning these coils helps your unit cool your house more efficiently, and it lowers energy bills. According to the U.S. Department of Energy, a dirty evaporator or condenser coil can increase energy usage by 30%.

4. Straighten Coil Fins

Coil fins are designed to remove warm air from the system while it’s running. If you find a bent coil fin on the outdoor AC unit, take the following steps to straighten it:

  1. Remove the panel to gain access to the fins.
  2. Determine which fin comb head fits your coils. Most fin combs have interchangeable heads.
  3. Spray a mild dish soap on the bent fins to lubricate them.

Start at the bottom of the condenser and slowly move upward as you straighten the thin metal slats.

5. Unclog Drain Channels

Your air conditioner’s condensate drain line is a tube that runs through the unit and leads outside. Dust that mixes with condensation can clog your drain with a mud-like buildup that can lead to flooding inside your home. Clean your drain channels by following the steps below.

  1. Remove and clean the drain pan, which is a metal pan under your evaporator coils.
  2. Connect a wet/dry vacuum hose to the drain line’s end and secure it with duct tape.
  3. Run the vacuum for a few minutes to clear debris.
  4. Place a garden hose in the drain line from inside your house, and flush the line with water. The water will flow outside.
  5. Pour a mixture of equal parts warm water and white vinegar down the line. Allow the mixture to sit for 30 minutes before flushing it.

6. Verify Proper Airflow Around the Unit

Proper airflow is critical for the overall function of your unit. If you notice poor airflow, check your ductwork for debris, leaks, and crimps. If your ducts are clean, check for the variables listed below, which might be restricting airflow: 

7. Level the Condenser Unit

Your AC unit needs to sit on level ground to function properly. If it isn’t on balanced ground, the refrigerant won’t flow smoothly and the fan motor will accelerate, which will wear out the unit. The unit can also vibrate excessively, which may lead to the loss of refrigerant or put additional stress on individual components.

Use a level tool to determine whether your AC unit is off-balance or lopsided. If it is, take one of the following methods to level it:

Take the DIY approach to leveling your AC unit only if you have the proper tools and related experience. Consider hiring a professional to handle this type of HVAC maintenance otherwise.

When to Hire a Professional

Even the best AC brands require routine maintenance, and some maintenance is better left to a professional HVAC contractor. Call a professional maintenance company to address the following situations: 

Room Air Conditioners

Follow the maintenance tips below to ensure your window air conditioner units function properly. 

Our Recommendation

Cleaning your AC system helps improve energy efficiency, cool your home effectively, and extend your unit’s life span. We recommend taking the DIY approach to HVAC maintenance if you have experience but contacting a professional if you don’t.

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Air Conditioner Maintenance FAQ

How often do AC units need maintenance?

AC units need maintenance at least once a year. An HVAC professional will inspect your system, clean its individual parts, and perform any necessary services. Change your air filters once or twice per season.

How do I check the Freon in my air conditioner?

To check the Freon in your air conditioner, turn the unit off, locate the pressure gauge and refrigerant lines on the unit’s side, and check the refrigerant levels.

How often should the air filters on my AC unit be cleaned or replaced?

You should clean or replace air filters on your AC unit every 90 days or sooner if you live in a dry or dusty climate. Change air filters every two months if you have pets in your home or you suffer from allergies.

What are the signs of a broken AC?

The signs of a broken AC include the system blowing warm air, the system not turning on, the system making unusual noises, or the system leaking. Your system may be malfunctioning if it’s producing humidity or turning on more frequently than it usually does.

What are some signs that my AC needs to be serviced?

Some of the signs that your AC needs to be serviced include warm air blowing from the unit, high electricity bills, poor airflow, and a malfunctioning AC thermostat.