A dirty filter is one of the most common reasons a split system air conditioner starts working harder than it should. The good news is that cleaning your filter is one of the easiest maintenance jobs you can do yourself, and it usually takes less than fifteen minutes.
Below, we explain why filter cleaning matters, how often to do it, and the simple steps you can follow to clean your split system filter safely.
Quick summary
If your split system filter is clogged, your air conditioner may have weaker airflow, higher running costs and reduced cooling or heating performance.
For most Perth homes, it is worth cleaning the filter every four to six weeks during heavy-use periods. The filter should be vacuumed, washed with lukewarm water if needed, dried completely and reinstalled before the unit is turned back on.
If your air conditioner still smells musty, leaks water, has weak airflow or is not cooling properly after the filter has been cleaned, it may need a professional service.
Why cleaning your split system filter matters
Your split system filter catches dust, pet hair, lint and other airborne particles before they move through the indoor unit. Over time, this build-up can block airflow and force the system to work harder to cool or heat your home.
When your filter is clogged, you may notice:
- Higher energy bills
- Weaker airflow from the indoor unit
- Reduced cooling or heating performance
- Dusty or musty smells when the unit is running
- More strain on internal components
- The system taking longer to reach the set temperature
A clean filter helps your split system run more efficiently, keeps airflow moving properly and reduces unnecessary wear on the unit.
If you want a broader look at what routine servicing covers beyond the filter, our air conditioner maintenance guide explains what is usually checked during a professional service.
How often should you clean a split system filter?
For most Perth homes, we recommend cleaning your split system filter every four to six weeks during heavy-use periods. This usually means summer, when your air conditioner is cooling the home, and winter, when reverse cycle systems are used for heating.
You may need to clean the filter more often if:
- You use the system every day
- You have pets inside the home
- Someone in the home has allergies or asthma
- You live near a busy road, construction site or dusty area
- The unit is installed in a bedroom, living room or high-use space
A filter clean is not the same as a full service. Most homes still benefit from professional air conditioner servicing once a year, especially before summer or before peak winter use.
How to clean your split system filter
Before you start, check your owner’s manual if you have it available. Most wall-mounted split systems follow a similar process, but brands such as Daikin, Mitsubishi Electric and Toshiba can have slightly different panel and filter designs.
1. Turn off the unit
Switch off your split system using the remote, then turn it off at the wall if possible. Never remove the filter while the unit is running.
This keeps the process safer and prevents dust from being pulled further into the system while you are working.
2. Open the front panel
Gently lift the front cover of the indoor unit. On most split systems, the panel is hinged at the top and should lift open with light pressure.
Do not force it. If the panel feels stuck, check the manual or look for small release tabs on either side.
3. Remove the filter
The filter is usually located directly behind the front panel. It will normally slide or lift out.
Hold the filter carefully by the frame and remove it slowly. If there is a lot of dust on the filter, try not to shake it inside the room.
4. Vacuum loose dust
Use a vacuum cleaner with a soft brush attachment to remove loose dust, lint and pet hair from both sides of the filter.
This step is helpful before washing because it removes the dry debris first and makes the rinse more effective.
5. Wash the filter with lukewarm water
Rinse the filter under lukewarm running water. For heavier grime, use a soft brush and a small amount of mild detergent.
Avoid hot water, harsh chemicals and stiff brushes. These can damage or warp the filter mesh.
6. Let the filter dry completely
Shake off excess water and place the filter in a shaded, well-ventilated area to dry.
Do not put the filter back in while it is damp. A damp filter can encourage mould or mildew growth inside the unit.
Avoid drying it in direct sun or using a hair dryer, as too much heat can damage the filter.
7. Reinstall the filter
Once the filter is completely dry, slide it back into place. Make sure it sits evenly and is not bent, loose or caught on the frame.
Close the front panel gently until it clicks or sits securely.
8. Turn the system back on and test airflow
Switch the unit back on and let it run for a few minutes.
Check that the airflow feels stronger and that the unit is running normally. If the airflow still feels weak after cleaning the filter, there may be another issue inside the system.
Signs your split system needs more than a filter clean
Cleaning the filter can fix many common airflow and performance issues, but it will not solve every problem.
You may need a professional inspection if:
- The air conditioner is still not cooling or heating properly
- Airflow remains weak after cleaning the filter
- The unit has a persistent musty smell
- Ice is forming on the indoor or outdoor unit
- Water is leaking from the indoor unit
- The system is making unusual noises
- The unit turns on and off more often than usual
- Your power bills have increased without an obvious reason
If your split system still is not blowing cold air after cleaning the filter, our guide on 7 reasons your split system isn’t blowing cold air explains some of the most common causes.
Can you clean the inside of a split system yourself?
You can safely clean the removable filter yourself, but deeper internal cleaning should be handled by a qualified technician.
The coils, fan barrel, drain tray and electrical components are more delicate. If they are cleaned incorrectly, you may damage the unit or create a safety risk.
A professional service can include:
- Filter cleaning
- Coil inspection
- Drain check
- Airflow check
- Electrical inspection
- Outdoor unit inspection
- Performance testing
- Advice on any worn or faulty parts
This is especially important if your system has not been serviced in a while, smells musty, leaks water or struggles to cool the room.
FAQs about cleaning split system filters
Can I run my split system without the filter?
No, you should not run a split system without the filter installed. The filter helps stop dust and debris from entering the indoor unit. Running the system without it can make the internal components dirty faster and may affect performance.
Can I wash a split system filter with soap?
Yes, you can use a small amount of mild detergent if the filter is greasy or very dirty. Rinse it thoroughly afterwards so no residue is left behind. Avoid harsh chemicals, bleach or strong cleaning sprays.
Why does my air conditioner smell even after cleaning the filter?
If the smell remains after cleaning the filter, there may be mould, bacteria or trapped moisture inside the indoor unit. The drain tray, coil or fan barrel may need professional cleaning.
Does cleaning the filter improve cooling?
Yes, cleaning the filter can improve cooling if the filter was blocking airflow. A clean filter allows air to move through the indoor unit more easily, helping the system cool the room more effectively.
Talk to the split system experts
Regular filter cleaning is a simple way to keep your split system running well, but it does not replace a full professional service.
If your air conditioner is due for a check-up, not cooling properly or showing signs of poor airflow, Hurricane Air can help. We provide scheduled air conditioner servicing across Perth, including filter cleaning, coil inspection and full system performance checks.
Get in touch with Hurricane Air today to book your next split system service.
