A clogged filter is the cheapest air conditioning problem you’ll ever fix: 20 minutes, no tools, and it’s safe to do yourself. Here’s how to clean split-system and ducted filters, and how often to do it.
Key Takeaways:
- Cleaning your air filters routinely can cut your air conditioner’s energy consumption by 5-15 per cent (US Department of Energy).
- Clean filters every four to six weeks during heavy use; most rinse clean under a tap and air-dry in around 20 minutes.
- A filter clean isn’t a service: coils, refrigerant, drains, and electrics still need a professional check once a year.
Why Clean Your Air Conditioner Filter?
A dirty filter restricts airflow, forcing your system to work harder. The US Department of Energy’s home cooling guide puts the saving from routine filter cleaning at 5-15 per cent of your air conditioner’s energy consumption. Heating and cooling make up about 40% of energy use in the average Australian home, per CHOICE’s air conditioner buying guide, so that’s worth 20 minutes of your time.
A clogged filter also recirculates dust and, left long enough, coats the indoor coil. That’s when a DIY job becomes a professional service.
How to Clean a Split System Filter
Switch the unit off at the power point, then work through the steps below.
| Step | What to do |
| 1. Open the front panel | Lift from both bottom corners until it clicks |
| 2. Slide the filters out | They slide or clip out by hand; no tools needed |
| 3. Vacuum the loose dust | Use a brush attachment on both sides |
| 4. Rinse under a cool tap | Cool water only; no harsh cleaners |
| 5. Air-dry, then refit | Dry for around 20 minutes, then refit |
Never run the system with the filters out; the dust goes straight onto the coil.
How to Clean a Ducted Return Air Filter
Ducted systems have one main filter behind the return air grille, usually in your hallway ceiling or wall. Undo the latches, lower the hinged frame, and slide the filter media out. Vacuum it, rinse it under a cool tap, and let it dry fully before refitting. Our ducted air conditioning guide for Perth homeowners explains how the return air side works.
How Often Should You Clean Your Filter?
Every four to six weeks during heavy use; in Perth that means summer and mid-winter. Our guide to how often you should service your air conditioner covers the full maintenance rhythm, and what a professional service includes covers the coils, refrigerant, drains and electrics a filter clean doesn’t touch.
Frequently Asked Questions
No. Even for an afternoon, running without a filter lets dust settle on the indoor coil and fan, where it cuts performance and is far harder to remove. Refit the dry filter before switching back on.
Most split system and ducted return air filters are washable and last for years. Replace one that’s torn, warped or still grey after a rinse. Disposable media filters, found in some ducted systems, are swapped rather than washed.
That points to something deeper: a dirty coil, a duct problem or a failing fan. Check the signs your AC needs a professional service, then book a technician.
Filter Clean, but Due for a Proper Service?
A filter clean tides you over between services; it doesn’t replace one. Book a service with WestOz Trades and our refrigeration mechanics will handle the parts you can’t reach.
