Simple Filter Maintenance for Tenants Using Split System Air Conditioners

Split system air conditioners work best when the filter is kept clean enough to let air move through the unit properly. For tenants, basic filter care is one of the simplest ways to help keep the system cleaner between professional services, without opening up the whole unit or attempting any repairs.

This guide explains what to look for, what you can safely do yourself, and when it is time to stop and contact the property manager or a qualified HVAC technician.

Why filter care matters in a split system

The filter sits in the indoor unit and captures dust, lint and other airborne particles before they move through the coil and fan assembly. When the filter loads up with dirt, airflow can become restricted and the indoor unit can collect more dust than it should.

For tenants, good filter habits can make everyday use simpler and help the system stay cleaner between scheduled maintenance visits. It also makes it easier for the property manager or service contractor to spot issues early, such as blocked drainage, visible mould, damaged filter frames or an incorrectly fitted filter.

If a system is used in a dusty room, near a busy street, or in a property with pets, the filter may need checking more often than in a low-dust environment. Inspection frequency depends on the system, site conditions and dust load, and you should always follow the equipment manufacturer’s instructions.

Before you touch the unit

Make sure it is safe to open

Before removing the front panel, switch the system off at the remote and, if possible, at the isolator. Wait for the fan to stop completely.

Keep in mind that tenants should only carry out basic filter cleaning if the filter is easy to access and the manufacturer allows it. If the unit looks damaged, smells strongly of dampness, has visible mould growth inside, or the filter arrangement is unclear, stop and advise the property manager.

What you will usually need

• •A clean vacuum with a soft brush attachment
• •Lukewarm water if the product instructions allow washing
• •A soft cloth
• •A towel or drying area for removable filters

Some filters are designed to be washable - check the product instructions before using water. If the filter is not meant to be washed, do not soak it.

How to inspect the filter

Open the front cover carefully and locate the filter mesh or panel behind it. Most split systems use reusable mesh filters, although some units may have different filter styles depending on the brand and model.

Look for:

• •A visible layer of dust or lint
• •Discolouration that does not brush off easily
• •Tears, dents or warping in the frame or mesh
• •A loose fit when the filter is reinstalled
• •Signs of damp, mould or unusual staining

A filter that still looks mostly clean may not need washing yet, but it is still worth checking it regularly so dirt does not build up unnoticed.

Cleaning a reusable split system filter

Dry cleaning first

If the filter only has light dust, gently remove it and vacuum both sides using a soft brush attachment. Hold the filter steady so the mesh is not stretched or bent.

This is often the quickest option for light maintenance between services and can be suitable when the filter is only lightly loaded.

Washing when allowed

If the product instructions say the filter can be washed, rinse it carefully with lukewarm water. Use only mild cleaning methods approved by the manufacturer. Avoid harsh chemicals, hot water, scrubbing brushes or pressure washing, as these can damage the filter media or frame.

After washing:

• •Shake off excess water gently
• •Let the filter dry fully before reinstalling it
• •Make sure no moisture remains trapped in the frame or corners

Do not reinstall a damp filter, as moisture can contribute to dust sticking to the surface and may create other hygiene issues inside the unit.

Reinstalling correctly

Slide the filter back into place in the same orientation it was removed. It should sit flat and secure, without forcing it into the frame.

If the filter does not fit properly, stop and check whether it has been inserted the right way around or whether the frame is bent. A poor fit can allow dust to bypass the filter and settle inside the unit.

What tenants should not do

A split system is not the place for guesswork. Avoid the following unless the property manager or equipment instructions specifically say otherwise:

• •Opening sealed panels or electrical compartments
• •Spraying cleaners into the indoor unit
• •Trying to wash non-washable filter media
• •Bending or trimming a filter to make it fit
• •Removing parts that are not clearly designed for tenant access
• •Ignoring a damaged filter and continuing to run the unit

If the unit has a more complex filtration setup, or if replacement filters are required rather than washable ones, the property manager or building owner may want the correct product selected before any work is done.

When a replacement filter may be needed

Some split systems use replaceable filters or additional filter media that are not intended for routine washing. Others may need a custom-sized filter if the original has been damaged or if the unit uses an uncommon size.

If you are unsure what type of filter the system needs, it is often best to check the model details and compare them with the equipment instructions. You can also use how to measure an air filter as a guide when confirming dimensions for a replacement.

For properties with multiple units, or where filter access varies between rooms, keeping a simple note of each system’s model and filter size can save time later. If you need replacement products, our products page is a useful place to start.

Working with property managers and building owners

Tenants can help keep split systems cleaner, but the responsibility for the overall maintenance plan usually sits with the property manager or owner. If you are managing a rental property, it helps to set expectations clearly so tenants know what they can safely do and what should be left to a contractor.

For larger buildings or systems with wider ventilation requirements, site needs should be confirmed with the mechanical services engineer or building owner. If the installation forms part of a larger ventilation strategy, AS 1668.2:2024 may be relevant, but site requirements should always be confirmed for the specific building.

Where filters are difficult to source, need special sizing, or are part of a broader maintenance program, filter servicing and commercial filter servicing may be worth exploring.

Getting the right filter support

If a split system filter is damaged, missing, non-standard or due for replacement, Total Air Filtration can supply or make the right filter for the job. We are a family-owned air filter manufacturer and supplier in Hillcrest, Brisbane QLD, and we can help with common and custom requirements.

Call us on 07 3800 3448 or request a quote. If you are unsure what you need, contact us and we can help point you in the right direction.