ARTICLE
Air Conditioner Split System cleaning: Step-by-step
Published Sep 10, 2026 - 5 min read
You can clean a split system yourself in under an hour: switch it off at the power point, wash the filters in warm soapy water, wipe the vents, clear the drain and tidy around the outdoor unit. This guide walks through all nine steps, plus how often to repeat them.
Key takeaways from this article
Switch off at the power point first, and never clean a running unit.
Wash filters in warm soapy water and dry them fully in the shade before refitting.
Clean the filters every one to three months, and book a professional service yearly.
Book a technician for ice on the pipes, burning smells or mould you cannot reach.
Wondering how to clean your split system without booking a technician? Here’s the short answer: switch the unit off at the power point, wash the filters in warm soapy water, wipe down the indoor unit and vents, clear the drain, then clear leaves and debris from around the outdoor unit. Most people can work through the lot in under an hour, using things already in the cupboard.
This guide covers wall-mounted reverse cycle split systems, the most common type in Australian homes, including popular brands like Daikin air conditioning, Mitsubishi split system air conditioners, Fujitsu air conditioning, LG and Samsung. The steps are broadly the same whichever badge is on the front, though it’s always worth a quick look at your manual first. If you have ducted air conditioning or a multi-head system, the filter steps still apply, but ceiling and bulkhead units are usually best left to a professional.
Why regular split system cleaning matters
A clean split system moves air freely, which means it doesn’t have to work as hard, or run as long, to reach the temperature you’ve set.
Here’s what happens when it isn’t cleaned. Dust and lint collect on the filters and gradually restrict airflow. The unit keeps running to hit your set temperature, using more electricity while it does. At the same time, the moisture that naturally forms on the indoor coil has more dust to cling to, and that’s usually what’s behind a musty smell when the air conditioner first kicks on. Left long enough, that build-up gets blown back into the room every time the unit runs.
Regular cleaning also takes pressure off the components. A fan motor pushing air through a clogged filter is doing avoidable work, and that shows up over the life of the unit. Ten minutes on the filters every few months is the cheapest maintenance you’ll ever do.
If air quality is a priority in your home, it’s worth knowing that some models pair filtration with cooling. You can browse air conditioners with a built-in purifier to see how they work alongside a regular cleaning routine. And if you’re looking at running costs more broadly, our guide to the best appliances to save on energy bills is a good next read.
What you’ll need before you start
You don’t need specialist gear. Everything below is standard household kit.
Tools and supplies
Vacuum cleaner with a soft brush attachment
Two or three microfibre cloths
Warm water and a small amount of mild dish soap
Spray bottle
Soft brush or an old toothbrush for vents and grilles
Old towel or drop sheet to catch drips
Stable step ladder
Gloves, plus a mask if you can see mould
Safety checklist - read this first
Turn the unit off with the remote, then switch it off at the power point or the circuit breaker. Never clean a running unit.
Keep water and cleaning spray away from the electrical components, wiring and control board.
Use a proper step ladder on level ground, not a chair or a bench.
Let filters and surfaces dry completely before you reassemble and switch the power back on.
Leave refrigerant lines, gas, sealed internal parts and anything behind a fixed cover to a licensed technician.
Not sure exactly what you’re working with? Our guide to the best features of a reverse cycle air conditioner will help you identify your unit type and its filtration setup before you open anything up.
How to clean your split system air conditioner step by step
Work through these nine steps in order. Allow around 45 minutes for a full clean, plus drying time for the filters.
1. Switch off the power. Turn the unit off with the remote, then isolate it at the power point or circuit breaker. Give it a few minutes to stop completely before you touch anything.
2. Vacuum the outside of the indoor unit. Use the soft brush attachment along the top, the front face and the air outlet. This stops loose dust falling into the unit when you open it.
3. Open the front panel and remove the filters. Most panels lift up and click into place, holding themselves open. The filters are thin mesh screens that slide out from the top. Note which way around they sit.
4. Vacuum the filters, then wash them. Vacuum the dusty side first, then rinse under lukewarm water. For heavier build-up, soak them in warm water with a little dish soap for 10 minutes, rinse clean, and shake off the excess. Don’t use hot water, and don’t scrub the mesh.
5. Dry the filters properly. Stand them somewhere shaded and airy until completely dry. Skipping this is the fastest way to reintroduce the musty smell you’re trying to get rid of, and direct sun can warp the frames.
6. Wipe the vanes, grille and fan blades. With the filters out, wipe the front panel and the horizontal louvres with a damp microfibre cloth. You can gently rotate the vanes by hand to reach both sides. Wipe what you can safely reach of the barrel fan behind the outlet, using a cloth wrapped around your finger. Don’t force the blades.
7. Vacuum the indoor coil. The coil is the row of thin metal fins behind the filters. Vacuum lightly with the soft brush attachment, moving in the same direction as the fins. They bend easily, so use a light touch and never poke anything between them.
8. Clear the drain. Split systems drain condensation through a small pan and a hose that runs outside. Wipe out any sludge you can reach in the pan, then check the outdoor end of the drain hose is clear and dripping freely when the unit runs. A blocked drain is the usual cause of water dripping down an internal wall.
9. Clean the outdoor unit and reassemble. Clear leaves, cobwebs and garden growth from around the outdoor unit, leaving at least 30cm of clear space on all sides. Vacuum or gently hose the outer fins from the outside in. Then refit the dry filters, close the panel, restore power and run the unit on cooling for 10 minutes to check airflow and drainage.
How to remove mould from a split system
Mould shows up as black or dark green speckling on the filters, the vents or the visible edge of the coil, and it usually comes with a damp, musty smell.
For light surface mould, wash the filters as described above, then wipe the vents and accessible surfaces with a cloth dampened in a mild solution of white vinegar and water. Let everything dry fully before reassembling. Running the unit on fan-only mode for 20 minutes after cooling helps dry the coil and slows mould coming back.
If the mould is extensive, keeps returning after cleaning, or you can see it deep inside the unit where you can’t safely reach, book a professional air conditioner service. Deep coil and blower cleaning needs the unit partially dismantled, which isn’t a DIY job.
How often should you clean your split system?
Clean the filters every one to three months during periods of regular use, and book a professional service once a year.
Task | How often |
|---|---|
Vacuum and wash the filters | Every 1-3 months in use, monthly with pets, allergies or a dusty location |
Wipe vents, panel and fan blades | Every 3 months |
Vacuum the indoor coil | Every 6 months |
Check the drain is running clear | Every 6 months, and after heavy use |
Clear around the outdoor unit | Every 3 months, plus after storms or heavy leaf fall |
Full professional service | Every 12 months |
The simplest approach is to tie it to the seasons: a full clean before summer, a filter wash mid-season, another full clean before winter if you run reverse cycle heating. Homes with pets, smokers, or a unit near a busy road or building site will need the filters done more often.
Once your unit is running well, it’s worth checking you’re running it efficiently too. Our guide to the perfect air conditioner temperature for your home covers the settings that make the biggest difference.
Signs your air conditioner needs professional servicing
If your split system still isn’t performing after a thorough clean, that’s the point to bring in a licensed technician.
Book a service if you notice any of the following:
Poor cooling after cleaning.
Clean filters and clear airflow, but the room still won’t cool, often points to a refrigerant or compressor issue.
Ice on the pipes or coil.
A sign of restricted airflow or low refrigerant, and something to have looked at promptly.
Water leaking inside.
If the drain is clear and it’s still dripping, the pan or drain line may be blocked further along.
Burning, electrical or chemical smells.
Switch the unit off at the power point and call a technician before running it again.
Grinding, rattling or screeching.
Usually the fan motor or a loose component.
The unit trips the circuit breaker.
An electrical fault that needs qualified attention.
Error codes on the display or remote.
Check the manual, then quote the code when you book.
Age matters too. Split systems typically last around 10 to 15 years with regular maintenance. If yours is at that end of its life and needs repeated repairs, replacement is often the better value option. Our guide to the signs you need a new air conditioner walks through when cleaning is no longer enough, and the air conditioner buying guide covers sizing and features if you’re starting to compare. If you’d rather hand the whole job over, The Good Guys offers air conditioning installation with qualified installers.
Keep your home comfortable with The Good Guys
A regular clean keeps the split system you already own running the way it should, for the cost of a bit of warm water and 45 minutes. And when it’s time for an upgrade, The Good Guys has split system air conditioners from the brands you trust, in sizes to suit everything from a bedroom to an open-plan living area, with expert advice to help you match the unit to the room.
Looking for a new split system air conditioner, you’ll find it at The Good Guys. Shop the range or pop in store today.
Frequently asked questions
Clean the filters every one to three months during periods of regular use, and monthly if you have pets, allergies in the household, or live somewhere dusty. Give the vents, fan and coil a wipe every three to six months, and book a professional service once a year.
Switch the power off at the wall, vacuum the outside of the indoor unit, then open the panel and remove the filters. Vacuum and wash the filters in warm soapy water and dry them in the shade. Wipe the vents, panel and fan blades, lightly vacuum the coil, clear the drain, then clean around the outdoor unit. Refit everything once dry and run a test cycle.
You can do the regular maintenance yourself. Filters, vents, fan blades, the accessible coil surface, the drain and the outdoor unit surrounds are all safe DIY jobs with the power switched off. A licensed technician handles anything sealed or electrical, including refrigerant, deep coil cleaning, the control board and internal blower access.
Wash the filters in warm soapy water, then wipe the vents and accessible surfaces with a cloth dampened in a mild white vinegar and water solution. Dry everything completely before reassembling, and run the unit on fan-only mode after cooling to dry the coil. For mould that’s extensive or keeps returning, book a professional service.
The most common causes are dirty filters restricting airflow, a blocked or obstructed outdoor unit, incorrect remote settings, and doors or windows left open. Start with a full clean and check the mode and set temperature. If it still won’t cool, the likely causes are low refrigerant or a compressor fault, both of which need a technician.
Once every 12 months is the general recommendation, ideally before the season you use it most. An annual air conditioner service typically covers a deep coil and drain clean, refrigerant and pressure checks, electrical connections and overall performance, which is the part regular DIY cleaning doesn’t reach.
It can help. A clogged filter restricts airflow, so the unit runs longer to reach your set temperature, and drawing power for longer means using more of it. Clean filters and a clear outdoor unit let the system move air the way it was designed to, so it reaches temperature and cycles down sooner.
