What Is Included in a Professional Split System Deep Clean?

What is included in a professional split system deep clean?

My indoor split system deep clean includes the complete cleaning process below:

1. Inspect and test the air conditioner before cleaning
2. Isolate the power for safety
3. Protect the wall, floor, furniture and surrounding work area
4. Remove suitable filters, outer casing, louvres and accessible components
5. Clean the removable parts separately
6. Clean the indoor coil, fan barrel, drain tray and internal airflow path
7. Check the drainage and flush it where appropriate
8. Reassemble the air conditioner and test its operation
9. Clean and pack down the work area
10. Take before-and-after photos so you can see the internal result

The exact dismantling and access can vary by brand, model, age and condition. Some units have brittle clips, unusual covers or components that should not be forced. The goal is always to clean the suitable internal areas thoroughly without creating unnecessary risk or damage.

What does “deep cleaning” a split system actually mean?

The phrase “air conditioner clean” is used for very different services. One provider may remove and wash the filters. Another may spray cleaner at the front of the coil without removing the casing. A more complete internal clean requires preparation, controlled access, water containment and enough time to clean areas hidden behind the visible front panel.

For me, a split system deep clean means cleaning the parts that directly collect dust, grime and moisture inside the indoor head, not simply making the outside look cleaner.

The important internal areas include:

• The filters: The first layer that catches larger airborne dust.
• The evaporator coil: The tightly spaced fins that air passes through while the system heats or cools.
• The fan barrel: The long cylindrical fan that pushes conditioned air into the room.
• The drain tray or drain pan: The channel that catches condensation below the coil.
• The drain path: The route that carries condensation away from the indoor unit.
• The internal housing and airflow path: The surfaces the air passes over before leaving through the outlet.
• The removable casing and louvres: The visible components that can also collect dust and marks.

A clean-looking front cover does not tell you the condition of those components. Filters may be washed regularly while the fan barrel has never been properly accessed. The visible coil face may look reasonable while residue sits underneath it or within the drain tray.

You can see examples of the difference on my split system before-and-after results page. The purpose of those photos is not to make every air conditioner look dramatic. It is to show the actual internal condition and the result of the work completed.

What happens before the cleaning starts?

A proper clean starts before any water or cleaning product is applied. I first need clear access to the indoor unit, enough room for a ladder and cleaning equipment, and a safe path between the work area and where the equipment is set up.

When I arrive, I confirm which air conditioners are included in the booking and ask about any known issues. Useful information includes:

• Whether the unit has been leaking
• Whether it smells musty when first switched on
• Whether airflow has changed
• Whether it has displayed an error code
• Whether it has tripped power
• Whether it makes unusual mechanical or electrical noises
• Whether another technician has recently diagnosed a fault
• When it was last internally cleaned, if known

This matters because cleaning should not be used to hide or guess at an unrelated fault. A split system that will not operate, smells electrically burnt, trips a breaker or has visible wiring damage may need an appropriately qualified air conditioning or electrical technician before cleaning proceeds.

Step 1: I inspect and test the air conditioner

Before dismantling the indoor unit, I switch it on and check that it responds to the remote and operates normally enough to be cleaned.

The initial test gives me a baseline. Depending on the unit and the reason for the booking, I may check:

• Whether it starts and responds to basic controls
• Whether the fan runs smoothly
• Whether the louvres move correctly
• Whether there are fault codes or warning lights
• Whether airflow appears even across the outlet
• Whether there are obvious rattles, grinding sounds or electrical smells
• Whether water is already leaking from the unit
• Whether the casing, clips or louvres are damaged before removal

I also inspect the visible condition of the filters, coil, discharge opening and fan barrel where possible. A torch through the outlet can often reveal buildup that is not obvious from standing in the room.

The inspection is not a full mechanical service, but it helps separate a straightforward cleaning job from a unit that may have a pre-existing fault or require a different type of work.

Step 2: I isolate the power

Once the operating check is complete, I turn the air conditioner off and isolate the power before accessing and cleaning the internal components.

Split systems contain wiring, sensors, motors, connectors and control electronics. Their exact location and layout vary between brands and models. Water containment and protection are important, but they do not replace safe isolation.

This step is one reason a professional internal clean should not be treated like spraying an ordinary household appliance. The cleaning area sits close to components that must stay dry and protected.

I also take care not to assume that every older unit has the same isolation setup as a newer installation. If the unit cannot be isolated or accessed safely, the correct response is to stop and discuss the issue rather than improvise.

Step 3: I protect the surrounding area

Before internal washing begins, I prepare the room and install purpose-built water containment around the indoor unit.

The protection stage normally includes:

• Creating clear space directly below the air conditioner
• Protecting the wall and floor
• Moving or covering nearby items where necessary
• Positioning a cleaning bag around the indoor head
• Directing dirty runoff into a suitable container
• Protecting the electrical area from overspray
• Checking that the bag and drainage hose are secure before washing

The purpose-built bag catches the water and loosened debris removed from the system. This allows the internal coil, fan barrel and airflow path to be cleaned while keeping the wall and floor protected.

Good containment also makes the result easier to see. The dirty runoff often reveals how much material was sitting inside a unit that appeared reasonably clean from the outside.

The cleaning result matters, but so does how the job is completed. A proper deep clean should not leave dirty water on the wall, dust across the room or a mess for the customer to clean afterwards.

Step 4: I remove the filters, outer casing and louvres

With the power isolated and the area protected, I remove the suitable accessible components needed to reach the internals properly.

A typical unit may allow removal of:

• The washable mesh filters
• The front cover or intake panel
• The main outer casing
• The horizontal outlet louvre
• Suitable vertical vanes or other accessible pieces

Removing these parts provides better access to the coil, fan barrel, drain area and internal housing. It also allows the removable plastic pieces to be washed separately instead of simply wiped while they remain attached.

However, not every component should be forced off every unit. Plastic becomes more brittle with age, clips vary between manufacturers and some models are designed differently. If a part is damaged, seized or creates unnecessary risk, I adjust the cleaning method rather than breaking it to follow a rigid checklist.

This is also why dismantling a split system is different from removing ordinary household filters. The aim is controlled access, not stripping every possible component regardless of condition.

Step 5: I clean the removable components

The filters, casing, louvres and other suitable removable pieces are cleaned separately.

These parts can collect:

• Loose household dust
• Sticky residue
• Marks around the air outlet
• Dark spotting on the rear of the louvres
• Fine buildup within the filter mesh
• Debris around clips, edges and corners

Filters are washed carefully and allowed to drain before reinstallation. The casing and louvres are cleaned without using a method that scratches the finish or damages thin plastic components.

Cleaning these pieces is important, but it is still only one part of the service. A filter and casing clean can improve the visible appearance while leaving the main internal buildup untouched.

My guide on DIY air conditioner cleaning kits explains this difference in more detail. Homeowners can and should maintain suitable filters, but most basic kits do not provide the same access to the entire fan barrel, drain area and internal airflow path.

Step 6: I clean the coil, fan barrel, drain tray and airflow path

This is the main internal cleaning stage.

The indoor head is protected and contained so the internal components can be cleaned with controlled application and rinse water. The method is designed to loosen and remove buildup rather than push it deeper into the unit or spray it around the room.

The evaporator coil

The evaporator coil is made from rows of closely spaced fins. Room air is drawn through the filters and across this coil before being moved back into the room.

Fine dust can collect on and between the fins, particularly when filters are damaged, poorly fitted, rarely cleaned or simply unable to capture very small particles. Moisture forms on the coil during cooling, which can help residue cling to the surfaces.

I clean the accessible coil using controlled water flow and suitable cleaning products where required. The fins are delicate, so this is not a job for aggressive brushing or high-pressure washing.

The fan barrel

The fan barrel, also called the blower wheel or cross-flow fan, is the long cylindrical component that pushes air out through the bottom of the indoor unit.

Its narrow blades can collect a sticky layer of dust and dark grime. Because it sits deeper behind the coil and above the outlet, it is commonly missed by filter-only and surface-level cleaning.

A heavily coated barrel may contribute to:

• Reduced airflow
• Uneven airflow across the outlet
• Musty or stale odours
• Visible particles around the discharge opening
• Dirty internal surfaces even when the filters look clean

I work along the accessible length of the barrel and rotate it carefully so the individual sections can be cleaned. The dirty material is washed into the containment bag rather than left sitting underneath the coil.

The drain tray or drain pan

Condensation from the indoor coil falls into the drain tray before leaving through the drain line. Fine debris, residue and biological buildup can settle in this area over time.

The tray can be partly hidden behind the coil and casing, which is why spraying the visible coil face does not necessarily clean it.

I clean the accessible drain area and remove loose buildup that could contribute to odour or poor drainage. The amount of access varies between models, and some trays are integrated more deeply into the indoor head than others.

The internal housing and airflow path

The air leaving the fan moves through internal plastic surfaces and out through the louvres. Dust and grime can collect along this path, including around the underside of the coil, behind the outlet and near the ends of the fan barrel.

I clean the accessible internal housing so the job does not stop at a bright-looking coil while the outlet path remains dirty.

Step 7: I check and flush the drainage where appropriate

As the indoor coil creates condensation, that water must collect in the drain tray and leave through the drain line.

During the cleaning process, I check that the accessible drain area is clear and that water is moving through the expected path. The drain can be flushed where appropriate as part of the service.

This helps remove loose residue and confirms that the cleaning water is leaving the unit rather than backing up in the tray.

However, a drain check during cleaning does not mean every water leak is caused by dirt or can be fixed by flushing. Other possible causes include:

• A cracked or damaged drain tray
• A disconnected, kinked or poorly graded drain hose
• Installation problems
• Damaged pipe insulation
• A frozen indoor coil
• A restriction beyond the accessible cleaning area
• Water entering from another source

If a unit has been leaking, tell me before the appointment. Cleaning may solve a straightforward dirty drain issue, but I will not present it as a guaranteed repair for every leak.

Step 8: I reassemble the air conditioner and test it

Once the internal areas and removable components have been cleaned, the unit is reassembled carefully.

This includes refitting suitable louvres, vanes, covers and filters, checking that clips are seated correctly and making sure nothing has been left loose inside the air conditioner.

Power is then restored and the system is tested again.

The post-clean test may include checking:

• That the unit starts correctly
• That the fan and louvres operate
• That airflow is present across the outlet
• That there are no unexpected noises caused by reassembly
• That water is not leaking from the indoor head
• That the remote and basic controls respond
• That the unit appears to be operating consistently with the pre-clean test

This final test is important because a clean is not complete simply because the components look better. The air conditioner must also be put back together correctly and left operating as expected.

Step 9: I clean and pack down the work area

After the system has been tested, I remove the cleaning bag, pack down the protective materials and clean the immediate work area.

The final pack-down includes checking the wall, floor and surrounding surfaces, removing any water or debris from the setup and returning the space to a usable condition.

You should not be left with:

• Dirty water on the wall
• Dust and loosened grime on the floor
• Wet filters sitting nearby
• Loose screws or clips
• Cleaning equipment blocking the room
• A mess that becomes your responsibility after I leave

Respect for the home is part of the service, not an optional extra. You can view the full service scope on my air conditioner cleaning services page.

Step 10: I take before-and-after photos

Before-and-after photos provide proof of the internal condition and the work completed.

The useful photos are not just a picture of the outside cover. They should show an internal area where the change can actually be seen, such as:

• The fan barrel
• The coil and internal housing
• The air outlet and airflow path
• The filters and removable components
• The drain area where visible
• The dirty runoff removed during the clean

Not every unit produces dramatic black water, and I do not believe a service should be judged by how shocking the runoff looks. A regularly maintained air conditioner may only have moderate dust and light buildup. The purpose of the photos is to document the genuine condition, not manufacture a dramatic result.

You can compare more genuine jobs on the SEQ Air Care before-and-after gallery.

A real split system deep clean from one complete Dakabin job

The photos below are from the same split system cleaned in Dakabin on 28 July 2026. The air conditioner had previously been professionally cleaned about 13 months earlier, so this was a useful example of routine maintenance rather than an extreme neglected unit.

The job included cleaning the filters, evaporator coil, fan barrel, drain, casing, louvres and internal surfaces, followed by reassembly and an operational check.

You can view the full job record, including its findings and completed work, on the Dakabin split system deep-clean job page.

This example is important because a deep clean is not only for air conditioners with extreme mould and years of neglect. Routine internal maintenance can remove the buildup that has returned since the previous clean and keep the unit easier to maintain.

What is the difference between a deep clean and washing the filters?

Washing the filters is good homeowner maintenance. It should be done according to the instructions for your air conditioner and more often when the system runs frequently or the home has pets, dust or smoke.

But filters are only the first part of the airflow path.

Clean filters do not automatically mean the whole air conditioner is clean. Fine material can pass through the mesh, and dust may have accumulated during periods when the filters were clogged, damaged or poorly fitted.

Exactly what is included in my split system deep clean

What is not included in an air conditioner deep clean?

A cleaning service should have clear boundaries. Removing dirt does not turn the appointment into every type of air conditioning work.

My standard split system deep clean does not include:

• Refrigerant testing, charging or leak repair
• Electrical diagnosis or circuit-board repair
• Compressor, motor or sensor replacement
• Repairing damaged drain trays or drain pipes inside walls
• Correcting poor installation or pipe grading
• Removing an indoor unit from the wall
• Cleaning ducted, cassette, window or commercial systems under the standard wall-mounted split-system price
• Guaranteeing that permanent staining will disappear
• Guaranteeing a specific reduction in the electricity bill
• Guaranteeing that cleaning will fix poor cooling caused by a mechanical fault or undersized unit

If your main concern is price and whether the service represents good value, my article on air conditioner cleaning costs in Brisbane explains the current pricing, multi-unit totals, expected results and situations where cleaning may not be worthwhile.

If your main concern is a musty smell or black material around the outlet, see my guide to musty air conditioner smells and black buildup.

How long does a professional split system deep clean take?

I generally allocate about 45 minutes for each indoor unit within the booking schedule. The full time at the property can be longer once arrival, setup, protection, pack-down and discussion are included.

For a single unit, allow roughly 60 to 90 minutes at the property depending on:

• The model and design of the air conditioner
• The age and condition of the plastic components
• How easily the unit can be accessed
• The amount and type of internal buildup
• Whether there is an existing drainage concern
• How much furniture needs to be protected or moved
• Whether an outdoor cleaning add-on is included
• Whether multiple indoor units are being completed in one visit

A straightforward unit may be finished sooner. A heavily loaded system, awkward installation or older casing with brittle clips may require more time.

I would rather allow enough time to protect the home, clean the internal areas properly and test the air conditioner than rush through a fixed checklist.

How should you prepare for an air conditioner deep clean?

You do not need to empty the room or leave the house. A few simple preparations make the appointment easier:

1. Clear the space below the indoor unit. Move fragile items, electronics and small furniture where practical.
2. Provide safe ladder access. The floor directly below the unit should be clear enough for equipment.
3. Have the remote available. I need to test the system before and after cleaning.
4. Mention known problems. Tell me about leaks, fault codes, breaker trips, unusual smells or noises.
5. Keep pets and young children away from the immediate work zone. They can remain elsewhere in the home.
6. Make sure the unit can be powered and tested. Unless there is a known safety concern, the system should be available for the initial operating check.
7. Clear access to any booked outdoor unit. Move loose storage, toys or garden items where possible.

Most customers continue with their day in another room while I work. You only need to be available if I need to discuss an existing fault, unusual access or something found inside the system.

What can you realistically expect after a deep clean?

The clearest guaranteed result should be a visibly cleaner internal system within the accessible service scope.

Depending on the starting condition, customers may also notice:

• A fresher smell when the air conditioner starts
• Less visible dark buildup around the outlet
• Cleaner filters, casing and louvres
• Stronger or more even airflow when dirt was restricting the fan or coil
• Less dust and grime sitting directly in the airflow path
• Cleaner drainage through the accessible tray and drain path
• Confidence from seeing before-and-after proof

Results vary because not every performance problem is caused by dirt. A clean cannot make an undersized unit larger or repair refrigerant, sensor, motor or compressor faults.

A dirty system can sometimes use more electricity because buildup restricts airflow or heat transfer, but I do not promise a specific saving. My separate guide explains how a dirty air conditioner may affect the power bill and the other factors that influence running costs.

Who is a professional split system deep clean best suited to?

A deep clean is particularly useful when:

• The fan barrel has visible dust or dark buildup
• The air conditioner smells musty when it starts
• The filters are clean but the airflow still feels restricted
• There are dark marks around the air outlet or louvres
• The unit has not been internally cleaned for years
• The home has pets, smoke, renovation dust or frequent air conditioner use
• You want proof of what was found and cleaned
• You have several units and want them completed during one visit

A clean may be less urgent when the unit is lightly used, internally clean, odour-free and moving air normally. It may also be poor value when the system is severely damaged or already due for replacement.

You can check whether I service your suburb through the SEQ Air Care service-area directory.