How to maintain your window air conditioner

Your window air conditioner needs regular care and maintenance to operate as effectively and efficiently as possible. From cleaning a dirty air filter and coils to combing the fins on your window air conditioner, follow these tips to stay cool and control your energy costs.

If you're having problems with your window unit, you can find easy-to-follow repair guides and videos, troubleshooting tips and how-to advice on our DIY window air conditioner repair page.

Clean the window air conditioner air filter

The evaporator coil in the window air conditioner absorbs heat from air that passes over the coil. An air filter protects the evaporator by removing and trapping dust and pollen from the air that flows over the coils. When the filter gets dirty or clogged, the air conditioner works harder to cool the room because not enough air reaches the evaporator.

If the filter is reusable, remove it and clean it once a month. Follow the instructions in your owner's manual when cleaning the air filter; most just need warm, soapy water for a thorough cleaning. If the filter isn't washable, replace it every 2 months or so.

Clean the coils and fins

Like the evaporator coil, the fins are a part of the evaporator; the fins offer a broader surface area for heat to be absorbed from the air. Even if you've been diligent in keeping the air filter clean, dust still builds up on the evaporator coil and fins. This accumulation of dust on the coil and fins prevents the heat in the air from being removed, because the warm air can’t reach the evaporator.

Once a year, use a vacuum fitted with a soft dust brush nozzle to gently remove dust from the fins and coils. As you vacuum, look for bent fins inside the window air conditioner. Bent fins don’t work as well as straight fins at removing heat from the air. Use a fin comb with teeth that match the number of fins per inch on your unit (use a ruler to measure yours) to gently straighten the fins.

Clean the inside of the window air conditioner

Clean the inside of the window air conditioner once a year, following the instructions in your owner's manual or the steps below.

1. Unplug the unit and remove the front panel.

2. Disconnect and detach the green ground wire from the cabinet.

3. Have someone help you remove the main body of the air conditioner from the cabinet, being careful of sharp edges.

4. Carefully and thoroughly wrap the fan motor, electrical control box and electrical terminals in aluminum foil to protect them from water (some manufacturers recommend plastic wrap, but we have found that plastic wrap can come loose).

5. Clean the base, condenser coil, evaporator coil and condensate pan with a steady stream of water from a hose.

6. Let the unit air dry completely before reinstalling the window air conditioner.