How to Clean an Air Conditioner Window Unit

Prepare for Cleaning

• Unplug the air conditioner. “Always unplug the unit from the receptacle before cleaning to avoid electrical shock,” Copeland says.
• Open windows or work outside to ensure adequate ventilation while using cleaners.
• Wear personal protective equipment, including eyewear and gloves, to protect from sharp fins and protruding screws.
• Lift the unit out of the window if you will be cleaning more than the filter and grille.
  • Grab a helper when lifting heavy A/C units.

Clean the Filter

• Remove the filter. “Filters are usually located at the front of the unit, and in some cases may be behind the front grill,” Copeland says.
• Rinse the filter with warm water.
• Use a mild detergent solution, like dish soap and water, if the filter is really dirty.
• Rinse well with clean water.
• Allow it to completely air dry before reinstalling.
• Examine and replace, if needed. “If the filter is damaged or excessively dirty and cannot be cleaned, consider replacing it,” Copeland says.

Clean the Grille

• Remove the grille, which may snap off or be held in place by screws. “Most grills can be detached easily,” Copeland says.
  • Check the manual for specific instructions for removing your grille to avoid damaging it.
• Wash in warm, soapy water with a soft brush or cloth.
• Rinse well with clean water.
• Dry thoroughly before reattaching.

Clean the Coils

“To be done properly, [this] will require the unit to be removed from the window,” Copeland says.

• Remove the unit’s outer casing to properly access the condenser and evaporator coils.
• “Use a soft brush or vacuum cleaner with bristle attachment to remove dirt and debris from the coils,” Copeland says.
• Take care not to bend the coils while cleaning. Bent coils restrict airflow and reduce A/C efficiency.
  • If coils are already bent, use a blunt tool like a credit card, butter knife or special fin tool to carefully straighten them.
• Use a foam cleaner made for air conditioners on really gross units. “Follow the product instructions carefully, as some cleaners may not be suitable for aluminum,” Copeland says.

Clean the Drip Pan, Blades and Exterior

• Wipe down the fan blades and other internal components with a soft brush and damp cloth. Copeland recommends a toothbrush for tight spaces.
• “Empty and clean the drip pan to prevent mold and mildew buildup,” Copeland says.
• Wipe down the housing with a mild detergent and a damp cloth.
• Rinse the cloth and wipe down the components again to remove residues.

Maintain Your Air Conditioner

• Inspect the filter weekly and clean as needed.
• Check the seals around the window “to ensure that there are no air leaks, which can reduce efficiency,” Copeland says.
  • Replace if damaged.
• “Regularly check the unit for signs of freezing/ice build-up on the coils, [and] damage or wear and tear, such as bent fins or unusual noises,” Copeland says.
• Call a professional (or get a new air conditioner), if the unit isn’t cooling effectively or it has other issues.
  • “Obtain service fees prior to calling out a professional, as it may not be cost-effective and may be cheaper to replace the unit,” Copeland says.
• Store your air conditioner (as needed) by removing it from the window, cleaning it and “storing it in a clean, dry area to prevent pest infestation, mold and mildew growth,” Copeland says.

About the Expert

James Copeland is the director of technical services for Prism Specialties, a leader in appliance restoration. Copeland has extensive experience installing, repairing and servicing industrial equipment.