Your air conditioner filter is the first line of defence between your system and the dust, pollen, pet dander and biological particles floating in your home’s air. When it’s working properly, you get clean air and an efficient system. When it’s clogged — which happens faster than most people expect in Queensland — you get reduced airflow, higher power bills, faster mould growth on the coil, and eventually, a system breakdown.

Here’s how often to clean it, how to do it, and when filter cleaning alone isn’t enough.

The Short Answer: Every 4–6 Weeks

For most Queensland households running AC regularly, cleaning the filter every 4–6 weeks is the right baseline. In cooler states with shorter AC seasons, 3-monthly cleaning is often cited — but in Queensland’s subtropical climate where systems run for 6+ months a year (and often year-round in coastal areas), more frequent attention is necessary.

Clean more often if:

• You have pets that shed fur
• Anyone in the household has asthma or allergies
• Your home is near a main road, construction site or dusty environment
• Your system runs more than 8 hours per day through summer

The seasonal trigger method: at minimum, clean your filter at the start of each season — before the heavy cooling season begins (September/October) and again when it ends (April/May). This is a simple reminder system that ensures filters aren’t left for 6+ months.

How to Clean Your Filter: Step by Step

1. Turn off the AC system at the unit or remote before opening the panel
2. Open the front panel — most split systems have clips on the left and right sides that release with light pressure
3. Locate the filter/s — usually one on each side of the return air section
4. Slide the filter out carefully and take outside
5. Tap gently to dislodge loose dust before washing
6. Rinse under cool, running water — from the clean side through to the dirty side — until water runs clear
7. Allow to dry completely in the shade before reinstalling (never in direct sun — can warp the frame)
8. Reinstall, close the panel, and restart the system

Don’t use detergent, chemical sprays or a pressure washer on AC filters. Stick to cool water and gentle handling.

Filter Cleaning by System Type

Split system air conditioners — The most common type in Queensland homes. Filters are accessible from the front panel and can be cleaned by a homeowner in 5–10 minutes. Split system AC cleaning by a professional includes the filter plus the evaporator coil, blower fan and drain — which filter cleaning alone doesn’t address.

Ducted air conditioning systems — Filters are usually located in return air grilles in the ceiling or at a central return air unit. These are accessible to homeowners in most cases, though the return air unit location varies. The coil and internal components of a ducted system require professional access. Ducted AC cleaning covers the full system including ductwork.

Cassette air conditioners — Installed in the ceiling with a four-way airflow pattern. The filter panel drops down for access in most models. Access is straightforward but the unit’s ceiling position means some care is needed handling the filter without dropping dust into the room. Cassette AC cleaning is recommended annually given the ceiling installation.

Signs Your Filter Needs Immediate Attention

• Reduced airflow from the vents (the system runs but doesn’t circulate much air)
• Musty or stale smell when the system is running
• Higher electricity bills without a change in usage
• Ice forming on the indoor unit (severely restricted airflow)
• Visible dust accumulation on the filter visible through the return air grille

All of these are signs of a filter that needed cleaning weeks ago. If you’ve noticed any of them, clean the filter and book a professional service — particularly if there’s a smell, which indicates mould has established on the coil.

The 99 People offer air conditioner cleaning for all system types across Brisbane, Ipswich, Gold Coast, Sunshine Coast and Noosa. Same-day bookings available — call 1300 099 778 or book online.