How to Clean a Split System Air Conditioner?
A dirty split system air conditioner doesn’t just look bad, it performs badly, too. Clogged filters and coils reduce airflow, force the compressor to work overtime and can lead to mould growth. Cleaning regularly:
- Improves cooling/heating efficiency
- Lowers energy bills
- Boosts indoor air quality
- Extends the life of your unit (10–15+ years with proper care)
Most manufacturers (like Daikin, Mitsubishi, Fujitsu) recommend cleaning filters every 1–3 months, depending on use and a full professional service once a year.
Cleaning requirements differ depending on the type of cooling system you have. Unlike refrigerated systems such as split systems, the evaporative cooling systems rely on water evaporation, which means maintenance focuses more on pads, water lines and hygiene rather than refrigerant coils.
Wondering how to clean a split system air conditioner properly? In this guide, we’ll walk you through safe, simple steps to clean your split system at home.
Important Safety Precautions for Split System Air Conditioner
Before you start cleaning your split system air conditioner, safety is non-negotiable:
- Turn off the power at the wall switch or circuit breaker.
- Use a stable stepladder if the indoor unit is high up.
- Wear gloves and eye protection.
- Cover the floor with old towels or plastic to catch drips.
- Never use harsh chemicals like bleach, petrol, or thinners – they can damage parts.
- Don’t touch electrical components or refrigerant lines.
- If you’re unsure about any step, stop and call a licensed technician.
Required Tools and Supplies to Clean Your Split System air conditioner
Before you begin, gather the following items:
- Vacuum cleaner with brush attachment
- Warm water and mild dish soap
- Soft brush or toothbrush
- Microfibre cloths
- Bucket
- Optional: AC coil cleaner spray (for deeper clean)
- Ladder (if needed)
Cleaning the Indoor Unit
1. Turn Off the Power and Prepare
Switch off the unit at the remote and isolate power at the switchboard. Wait a few minutes for it to cool down.
2. Clean the Filters
Open the front panel (usually lifts or clips open – check your manual). Slide out the filters (they’re mesh screens).
- Shake off loose dust outside.
- Vacuum both sides with the brush attachment.
- Wash in warm soapy water if they’re grubby (use a soft brush).
- Rinse thoroughly and air-dry completely (no rushing – wet filters can cause mould).
While the filters are out, gently vacuum visible dust from the coils and fins behind them. Be gentle, the aluminium fins are delicate.
3. Wipe Down the Exterior and Louvres
Use a damp microfibre cloth to wipe the front panel, louvres and casing. Avoid spraying water directly into the unit.
4. Check the Drain Line
If you can access it (some units have a visible drain pipe), pour a mix of white vinegar and water down it to clear blockages. This prevents leaks and mould.
5. Reassemble and Test
Once everything’s dry, pop the filters back in, close the panel, and turn the power back on. Run in fan-only mode for 30 minutes to dry out any moisture, great for preventing odours.
Cleaning the Outdoor Unit
1. Turn Off Power
Isolate at the switch.
2. Clear Debris
Remove leaves, grass, or dirt from around the unit (keep at least 60cm clearance for airflow).
3. Clean the Fins
Use a soft brush or garden hose (low pressure) to clear dust from the condenser coils. Avoid high-pressure washers; they can bend fins. If fins are bent, gently straighten with a fin comb.
4. Wipe the Casing
Clean the exterior with a damp cloth.
When to Call a Professional for Deep Cleaning the Split System Air Conditioner
DIY covers the basics, but for a thorough clean (especially if there’s mould, heavy buildup, or odours), get a pro in. This is a job for licensed technicians, it involves disassembling parts, handling chemicals safely, and avoiding warranty issues.
Signs you need pro help:
- Musty smells (mould alert)
- Water leaking inside
- Reduced airflow or poor performance
- Strange noises
- Unit over 5 years old without service
How Often Should You Clean Your Split System Air Conditioner?
- Filters: Every 1–3 months (more if dusty or pets/kids)
- Basic wipe-down: Every few months
- Outdoor unit: Twice a year
- Professional service: Annually
Tips for Keeping the Split System Air Conditioner Clean Longer
- Run fan-only mode occasionally to dry the internals.
- Use a timer or smart control to avoid overuse.
- Keep the area around both units clear.
A clean split system makes a massive difference, cooler summers, warmer winters and lower bills. Maintaining a clean split system air conditioner is not just about aesthetics; it is a critical factor in ensuring optimal performance, energy efficiency, and indoor air quality.
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Frequently Asked Questions
How to clean the inside of a split system air conditioner?
Cleaning the inside of a split system air conditioner usually involves removing and washing the filters, wiping the indoor vents, and lightly cleaning the evaporator fins. For deeper internal components like the fan barrel and drain tray, a professional clean is recommended. These areas can be damaged easily and often hold hidden mould, dust and moisture that basic surface cleaning won’t fully remove.
Is it possible to self-clean your air conditioner?
Yes, you can handle basic maintenance like cleaning or vacuuming filters and wiping the indoor unit casing. However, internal components, electrical parts, and drainage systems should be left to licensed technicians. DIY cleaning beyond filters can cause water damage, electrical faults, or reduced efficiency if done incorrectly, especially with modern split system air conditioners.
How to clean mould out of a split system air conditioner?
Light surface mould on filters can be cleaned with warm water and a mild detergent. However, mould inside the fan, coils, or drain pan requires professional treatment. DIY sprays often don’t reach the source and may spread spores. In Australia’s humid conditions, professional mould cleaning ensures safe removal and helps prevent health issues and recurring contamination.
What is the consequence of water entering a split system air conditioner?
Some moisture is normal, but excess water entering electrical components can cause short circuits, corrosion, or system failure. Water leaks may also indicate blocked drains or internal mould buildup. If water is dripping indoors or pooling around the unit, it’s best to turn the system off and have it checked to prevent costly damage and safety risks.
Is it acceptable to vacuum the split system air conditioner filter instead of washing it?
Vacuuming is fine for light dust between washes, but it doesn’t remove grease, mould, or fine particles. Washing filters with water provides a deeper clean and better airflow. For best results, Australian manufacturers generally recommend vacuuming weekly during heavy use and washing filters every few months, especially during summer cooling seasons.
How to clean the gunk out of my air conditioner?
“Gunk” is usually a mix of dust, moisture, and mould trapped inside the unit. Filters can be cleaned at home, but internal buildup in the fan and drain system needs professional cleaning. Leaving it untreated can cause smells, poor airflow, and higher power bills. Regular servicing keeps your split system running efficiently and safely.