The short answer
| System | Professional clean | What you can do in between |
|---|---|---|
| Split system | Every 12 months. Every 6 months with pets, asthma or allergies, near the coast, or if it runs most of the year. | Wash the filters every month or two while you're using it. |
| Ducted reverse cycle | Every 12 months, before summer. | Vacuum or wash the return air filter every 1 to 3 months. |
| Evaporative cooler | Every 12 months, before the first hot spell. | Keep the tank drained when it's not in use, if your model allows it. |
Why Perth is harder on air conditioners
Perth summers are long and hot, and most homes run the aircon hard from December to March. A lot of us use reverse cycle for heating in winter too, so the same coil is working most of the year with no rest.
Then there's the dust and sand. Dry easterlies, building sites in the new estates and sandy gardens all put fine dust in the air, and the filter and coil catch it. Near the coast, salt settles on outdoor units and speeds up corrosion. Inside the unit, the coil is cold and wet every time it runs — dust plus moisture is exactly what mould needs.
Signs your aircon is overdue for a clean
- A musty, damp or "dirty sock" smell when it starts up
- Black specks on the louvres or the wall under the unit
- Water dripping from the indoor unit
- Weaker airflow than it used to have
- It takes longer to cool the room, or the power bill has crept up
- Allergies or asthma flaring up when it's on
- For evap coolers: a swampy smell, or pads that look white and crusty with scale
Any one of those is worth a look. Two or more and the unit needs a proper clean, not just a filter rinse. If it smells, our guide on why your aircon smells explains what's going on.
What you can safely do yourself
- Split filters: switch off at the isolator, slide the filters out, rinse with lukewarm water, let them dry in the shade and put them back.
- Ducted return air filter: unclip the grille, vacuum or wash the filter, let it dry fully before refitting.
- Outdoor units: keep plants, leaves and stored junk well clear so it can breathe.
Leave the coil, the barrel fan and the drain to a professional. Sprays from the hardware store can push dirt deeper into the coil and block the drain — more on that in our DIY kit vs professional clean guide.
The best time to book in Perth
September to November. Your system is clean before the first heatwave, and you beat the December rush when everyone remembers their aircon at once. Send us a few photos and we'll email you a fixed price and a date.