How to Clean an Air Conditioner Filter
A clean filter alone changes cooling efficiency and smell. The trick is spraying water from the side opposite the dust.
What you need
Supplies
- A few drops of mild dish soap
Tools
- Vacuum brush attachment
- Soft brush
- Shower head
- Dry towel
How to do it
- 01
Turn off and unplug
Switch off the air conditioner and unplug it or flip the breaker. Opening the panel while it runs can put your hand near the fan.
- 02
Remove the filter
Lift or open the front panel, hold the filter tab and pull it down and out. Lay newspaper on the floor for falling dust and keep the filter level as you remove it.
- 03
Vacuum the dust first
Lightly vacuum the dusty side (the outer side) with a brush attachment. Removing dry dust first stops it turning to paste when you wash.
- 04
Spray from the opposite side
Rinse with lukewarm water from the side opposite the dust so the water pushes it out. For greasy filters, soak for 10 minutes in soapy water and sweep with a soft brush.
- 05
Dry completely in the shade
Shake off the water, pat gently with a towel and dry fully in the shade. Direct sun can warp the plastic frame and make it hard to refit.
- 06
Refit and dry with fan mode
Put the filter back, close the panel and run fan mode for 30–60 minutes to dry the inside. It is the easiest way to prevent odor and mold.
Be careful
- The thin metal fins behind the filter (the evaporator) bend even under a fingertip. Do not touch them with a brush or your hands.
- Water above 40°C (104°F) can warp the filter.
- If there is a strong musty smell or black spots inside the vents, have the unit professionally deep-cleaned.
Malkkeum tips
- Switching to fan mode for the last 10 minutes before turning off greatly reduces internal mold.
- Most modern units have an auto-dry setting. Turn it on.
- While you are at it, check that the outdoor unit is not blocked by objects or leaves.
Why filter cleaning matters
The filter catches dust before room air enters the unit. When it clogs, air flows poorly, so reaching the same temperature takes more electricity, and dust that gets through sticks to the internal coils and feeds mold. That musty smell when you switch on the AC usually comes from this internal mold.
If summer is over
When the cooling season ends, dry the inside along with cleaning the filter. Leaving moisture inside for months brings a strong smell back the first time you use it next summer. See how to clean and store your air conditioner for a full checklist.
FAQ
Is it the same for floor-standing units? Yes, only the filter location differs. On most floor-standing units the filter is low on the back or side. Check the manual.
