In short: once every 12 months suits most Sydney homes. Move to every six months if you have pets, if anyone in the house has asthma or allergies, or if the unit runs most of the year. Rinsing the filters yourself every few weeks helps in between, but it does not replace a proper clean.
Why 12 months is the usual answer
A split system pulls the air of your home across a cold, damp coil, over and over. Dust sticks to it, moisture sits in the drain pan, and over a year that becomes a layer you can see once the cover comes off. Twelve months is roughly how long it takes for that build-up to start affecting how the unit smells and how hard it has to work.
When six months is the better call
- Pets in the house. Hair and dander load up the filters and coil far faster.
- Asthma or allergies. If someone reacts to what is in the air, the unit that circulates that air is worth keeping clean.
- The unit runs most of the year. Cooling through summer and heating through winter is double the hours.
- You are near a main road or building work. More dust in, more dust on the coil.
Signs you have left it too long
You do not need a calendar to know. A musty smell when the unit first kicks on, visible dark specks on the blades behind the cover, water dripping from the indoor unit, weaker airflow, or the room taking noticeably longer to cool than it used to — any of those means the clean is overdue. If you are seeing dark growth, read our guide on mould in air conditioners.
What about the filters?
Rinse them every few weeks in warm water and let them dry fully before they go back in. It takes five minutes and it genuinely helps. What it does not do is reach the evaporator coil, the barrel fan or the drain line, which is where the growth that causes the smell actually lives.
Ducted systems
The same annual rhythm applies, but there is more to it — the ducts, the outlets and the return air filter all collect dust. See air duct cleaning for what a ducted service covers.
A simple schedule for a Sydney home
If you want something to put in the calendar rather than a rule of thumb, this is the rhythm that works for most houses here.
- Every few weeks, all year. Rinse the filters in warm water and let them dry fully before they go back in.
- Early spring, once a year. Book the deep clean before the first hot week. The unit has sat unused or on heating through winter, and this is when the coil and drain pan get sorted out.
- Autumn, if you run heating. A second clean here suits homes that use the system year-round, and it is the natural time to have the outdoor unit cleared of the leaves that came down.
- Whenever the smell comes back. That is the real signal, and it overrides the calendar.
Why spring is the busiest time to book
Almost everyone in Sydney remembers the aircon during the first hot spell, which is exactly when the diary fills up. If you can book in August or early September you get a wider choice of times. Leaving it until the first 35-degree week means waiting behind everyone who did the same.
What happens if you leave it longer
Nothing dramatic on day one. Over a couple of missed years, three things build on each other:
- The coil clogs. Air cannot move across it properly, so the system runs longer for the same temperature.
- The drain pan and line block. That is where water dripping from the indoor unit comes from, and it is the most common call-out we get in January.
- The smell sets in. Mould on a coil that has been damp for years takes a full strip-down to remove, not a quick pass.
None of it is unfixable. It just costs more time on the day than a unit that gets seen once a year.
Offices, rentals and holiday homes
Units that run eight hours a day in an office need looking at every six months, the same as a heavy-use home. A rental between tenants is worth a clean regardless of the date, because you rarely know what the last twelve months looked like. A holiday home that sits closed for months is the opposite problem: still air and damp coils, so a clean before the season rather than after.
Booking a clean
We cover Sydney metro, seven days a week, 7:00am to 7:00pm, and can usually get to you the same week. A split system deep clean is $249 + GST, fixed and confirmed before we start. Call 0483 928 714 or request a quote on our aircon cleaning page.
Find your area: we have pages for aircon cleaning in North Shore, Northern Beaches, Eastern Suburbs, Sydney CBD & Inner South, Inner West, St George & Bankstown, Sutherland Shire, Ryde, Parramatta, Hills District, Blacktown, Penrith, South West Sydney and Campbelltown & Camden.
Frequently asked questions
How often should an air conditioner be cleaned?
Once every 12 months suits most Sydney homes. Move to every six months if you have pets, if anyone in the house has asthma or allergies, if the system runs most of the year, or if you are near a main road or building work.
Can I just clean the filters myself?
Rinse them every few weeks in warm water and let them dry fully before they go back in. It genuinely helps, but it does not reach the evaporator coil, the barrel fan or the drain line, which is where the growth that causes the smell actually lives.
When is the best time of year to book?
Late winter or early spring, before the first hot week. That is when the diary is still open. Once the first hot spell arrives everyone books at once.
How do I know the clean is overdue?
A musty smell when the unit first starts, dark specks on the blades behind the cover, water dripping from the indoor unit, weaker airflow, or the room taking longer to cool than it used to.
Do ducted systems need cleaning as often?
The same annual rhythm applies, but there is more to it. The ducts, the outlets and the return air filter all collect dust, so a ducted service covers more than a split system clean.
