Your Window AC Is Probably Filthy—5 Easy Steps to Clean It Before Summer

Window AC units are perfect for cooling homes without central air conditioning, ensuring you stay comfortable during hot weather. However, like all household appliances, air conditioners require regular cleaning and maintenance to function well.

Cleaning a window AC unit is simple and significantly boosts its performance, ensuring it runs smoothly for many years. Regular maintenance can also lower energy bills and enhance air quality by eliminating dust and preventing mold and mildew.

Before You Begin

Experts suggest cleaning a window AC unit at least once a year, preferably before using it for the first time in the season. When in regular use, the filter should be cleaned monthly and replaced every three months if it's a replaceable type.

Signs that your air conditioner needs cleaning include visible dust, hair, or other debris build-up; the unit blowing hot air, which may indicate dirty coils; or a mildew smell. Unusual noises, such as ticking, often point to a problem with the air compressor, which should be serviced by a professional.

What You'll Need

Equipment / Tools

• Screwdriver
• Vacuum
• Soft-bristle brush

Materials

• Dish soap
• All-purpose cleaner
• Compressed air
• Bleach
• Household gloves
• Face mask
• Eye protection
• Microfiber cloths

Instructions

How to Clean a Window AC Unit

Clean air conditioner filters monthly when the unit is in regular use. When it's time to clean the filter, follow these basic maintenance steps to keep the unit running properly and to prevent mold and mildew.

Unplug the Unit

Always unplug the AC unit before cleaning to avoid the risk of electrocution.

Remove and Clean the Air Filter

Refer to the user manual to locate and remove the filter; you may need a screwdriver. Vacuum the filter using a handheld vacuum or a vacuum with a soft brush attachment. Then, wash the filter with a soft-bristle brush in lukewarm, soapy water, rinse well, and let it air-dry completely before reinstalling it.

Clean the Grille Cover

Open or remove the grille cover as per the manufacturer’s instructions. If removable, rinse it under cool running water or submerge it in soapy water and clean with a soft-bristle brush, sponge, or dishcloth. Dry it thoroughly before putting it back.

If the grill cover isn't removable, use a handheld vacuum, a vacuum with a dusting attachment, or a microfiber cloth to clean it. Then, apply all-purpose cleaner to a cloth and wipe the grille clean. Never apply liquid cleaning agents or water directly to the AC unit to prevent damage or electrocution.

Clean Coils and Fins

Gently clean the evaporator coils and fins with a soft-bristle brush to remove dirt and dust. Spray them with compressed air to remove any remaining build-up.

Be gentle to avoid bending or damaging these delicate parts.

Clean the Exterior and Reassemble the AC Unit

Wipe the exterior top and sides with a damp cloth. If there's a drip tray, remove it, empty it, clean it, and dry it before returning it. Ensure all parts are completely dry before reassembling.

How to Remove Mold and Mildew from a Window AC Unit

Air conditioners are prone to mold and mildew, especially if not maintained well. Signs include a musty smell when running and visible patches of mold, which are usually fuzzy and black or green-black. Severe infestations may require a professional or might mean the unit needs replacing. You can remove light mold colonies using these steps.

Remove the AC Unit from the Window

Wear household gloves, a face mask, and eye protection to prevent exposure to spores. Move the unit to an area where it can be cleaned safely, like a driveway or backyard.

Remove and Clean or Replace the Filter

Remove the filter and either replace it or soak it for 10 minutes in a solution of 1 part liquid bleach to 10 parts water. Rinse and let it air dry completely.

Deep Clean Air Conditioner Parts

Use the bleach solution to clean the parts of the AC unit. Dip a microfiber cloth or soft-bristle brush into the solution, wring it out to remove excess liquid, and wipe all surfaces where mold or mildew is present.

Rinse, Air Dry, and Reinstall

Rinse the unit by wiping it with a clean, damp cloth. Avoid soaking the electrical components. Allow the unit to dry completely before replacing the filter and reinstalling.