How to Clean an AC Filter and Window Unit
Window air conditioners are common in Toronto apartments and older homes. A dirty filter reduces airflow, makes the unit work harder, increases energy consumption, and degrades air quality by recirculating dust and allergens. Cleaning the filter monthly during heavy-use summer months is the single most effective maintenance step.
Cleaning the Filter
Unplug the unit before any cleaning. Remove the front panel (usually clips off or screws out) to access the filter — a rectangular mesh screen. Slide or lift out the filter. Rinse under warm running water from the clean side through to the dirty side, which pushes debris out rather than further in. For greasy or heavily clogged filters, soak in warm soapy water for 10 minutes and gently scrub with a soft brush. Rinse thoroughly and allow to air dry completely before reinstalling — a wet filter restricts airflow and promotes mold growth.
Cleaning the Coils
With the filter removed, you can access the evaporator coils (the aluminium fins on the interior). Use a vacuum with a soft brush attachment to gently remove dust from the fins — work vertically, not across the fins, to avoid bending them. Bent fins reduce efficiency and can be straightened with a fin comb. For stubborn grime, spray a no-rinse coil cleaner (available at HVAC supply stores or online) on the coils — it foams, lifts dirt, and drains out through the condensate drain.
Cleaning the Exterior
Wipe the exterior housing with a damp cloth and mild dish soap. Clear any leaves, debris, or dirt from the rear exterior coils — a garden hose on low pressure works well for the outdoor portion. Ensure the condensate drain at the bottom is not blocked — blocked drains cause water to overflow into the room.
End-of-Season Storage
- Clean the filter and coils before storing for the winter
- Cover the exterior with a fitted AC cover to prevent moisture and pest entry
- Store in a dry location if removing the unit — do not store on its side, which can damage the compressor oil
Professional Cleaning in Toronto
For a full home deep clean before or after AC season, Maidless Toronto offers flat-rate cleaning. Book at maidless.ca.