The split system air conditioner installation process runs roughly like this: pick the indoor and outdoor unit positions, mount both units, drill through the wall, run the refrigerant pipework and drain, complete the electrical connections, commission the refrigerant circuit, then test everything and hand it over.
Finished, a good installation looks like nothing much. One unit on the wall, one condenser outside.
What you don’t see is most of the work.
Pipework has to be routed properly. Condensation needs somewhere to go. The outdoor unit needs air. The electrical connection has to suit the equipment. And the refrigerant circuit has to be prepared correctly before anyone switches the thing on.
Which is why a good installation starts well before anybody drills a hole in your wall.
The eight main stages
Most standard installations break down like this:
- Inspect the room and confirm the system size
- Choose the indoor unit position
- Choose the outdoor unit position
- Mount both units
- Install pipework, drainage and interconnecting cable
- Complete the electrical work
- Test and commission the refrigerant system
- Run the system and hand over
The order shifts depending on the property. An apartment job can look nothing like a ground-floor installation in a freestanding house in Ryde.
Here’s what actually happens on the day.
First: the installer looks at the room
The first move shouldn’t be opening the box. It should be checking that the plan makes sense.
That means looking at room size, ceiling height, windows, insulation, sun exposure, where the indoor unit will go, where the condenser can go, what the wall is made of, how the pipework will run, where the water will drain, what the electrical supply looks like, and how accessible everything is.
If you’ve already bought the unit, the installer may also check whether its capacity actually suits the space — which is worth knowing before it’s on the wall.
Because a technically flawless installation can’t rescue a badly sized air conditioner. A 2.5 kW unit in a large, sunny open-plan living room will underperform no matter how neatly every pipe and connection has been done.
Where does the indoor unit go?
For a standard wall mounted air conditioning installation, the indoor unit sits high on a wall where it can push air across the room.
The easiest wall isn’t always the right wall, though. Mount it above a tall cabinet, behind a structural feature, or somewhere that blows air into a corner, and you’ll feel the difference.
Worth considering: how air actually moves through the room, where people sit or sleep, available wall space, distance to the condenser, the drainage route, and whether anyone can reach it for servicing later.
Above the bed? Sometimes it works. Often it doesn’t — plenty of people can’t sleep with air blowing straight down on them. A position that moves air across the room rather than directly onto the bed usually feels better. Let the room layout decide rather than defaulting to the obvious wall.
Where does the outdoor unit go?
The condenser gets treated as an afterthought far too often. It shouldn’t be — it has to move a serious volume of air while the system runs.
A good location needs adequate airflow, proper clearances, a stable mounting surface, a manageable pipe distance, reasonable service access, acceptable noise impact and no obvious obstructions.
What it shouldn’t be is wedged into the smallest available gap because that hides it best. Choke the airflow around a condenser and the system struggles to reject heat, which you’ll pay for in performance and running costs.
Apartments need more thought here. The condenser may have to sit on a balcony or another approved spot, and strata requirements can control where equipment, pipework and wall penetrations are allowed. Sort those questions out before installation day — not while a technician stands on your balcony with a condenser he can’t put anywhere.
The mounting plate goes up
Once the position is settled, physical work begins. Most high-wall splits use a metal mounting plate.
The installer positions it, checks it’s level, finds suitable fixing points and secures it. The unit needs to sit firmly and squarely, and the wall material changes how that’s done — plasterboard, brick and concrete all call for different approaches.
The wall gets drilled
The most recognisable of the air conditioner installation steps. An opening is made so the services can pass between the two units: refrigerant pipes, the condensate drain, and the interconnecting cable.
Both the location and the angle matter. The installer needs a route that lets pipework leave the indoor unit without being crushed or kinked, and the fall on the drain has to work.
Water is indifferent to how tidy your air conditioner looks. Get the drainage route wrong and you’ll find out eventually, usually somewhere inconvenient.
Refrigerant pipes are run
A split system exists in two pieces because heat moves between them through a refrigerant circuit. Connecting them properly is the technical heart of the job.
The pipes are insulated where required and routed between units. What the installer is avoiding: damaged pipe, poor bends, unnecessary restrictions, awkward routing and connections that might leak. Visible pipework outside usually gets enclosed in ducting or trunking for a cleaner finish.
Why this part is regulated. Refrigerant isn’t something to handle yourself. The Australian Refrigeration Council confirms that installing pre-charged split-system equipment requires an appropriate Refrigerant Handling Licence, and its licensing framework covers competencies in recovery, pressure testing, evacuation, charging and leak testing for split systems.
That’s the main reason this isn’t a wall-mounting job with extra steps.
The condensate drain
Cooling pulls moisture out of the air, and that moisture becomes water — sometimes a surprising amount of it on a humid Sydney day.
A drain connects to the indoor unit and carries condensate to an appropriate discharge point. Sometimes gravity handles it easily. Sometimes the layout makes it genuinely tricky.
Poor drainage eventually shows up as water leaking indoors, staining, smells, moisture damage or blockages.
On a simple back-to-back job the drain route is usually short and obvious. In an apartment, or a room where the ideal indoor position sits well away from an external wall, it takes real planning. It’s a big part of why two installations using the identical air conditioner can differ so much in difficulty.
The condenser is mounted
The outdoor unit gets secured in its planned position — on a concrete slab, on feet, on a balcony floor, or in another approved arrangement.
Stability, airflow and access are the priorities. So is vibration. A condenser shouldn’t be transmitting vibration through the building structure, and this matters most in apartments, where something that feels trivial standing next to the machine can be clearly audible in a neighbour’s bedroom.
Electrical connections
The system needs power and control connections, and the arrangement varies with the model and the property.
This is not the part to improvise. NSW Government guidance updated on 23 June 2026 states that a licence or certificate is required before carrying out air-conditioning and refrigeration work in NSW, and the licensing framework also deals with associated electrical wiring within the applicable scope of that licence.
The practical version for homeowners: ask who’s installing the system, and make sure whoever performs regulated work holds the right licence for it. A cheap installation isn’t good value if the electrical or refrigerant work is being done badly.
“Vacuuming the system” — what that means
This is the stage homeowners almost never see and rarely understand, and it’s one of the most important.
Before the system is commissioned, the refrigerant circuit has to be prepared. Air and moisture inside the pipework are both unwanted, so proper installation procedure includes evacuating the system with appropriate equipment, as applicable to the installation and the manufacturer’s requirements.
ARC’s current split-system licensing competencies specifically reference pressure testing, evacuation, charging and leak testing as part of refrigerant-handling work.
In plain terms, it’s making sure the circuit is genuinely ready to run as designed.
If someone connects the pipes and immediately flicks the system on without going through commissioning, that’s worth asking about.
Leak checks and commissioning
Commissioning means checking the completed installation before it’s handed over. Depending on the system and the work done, that can cover refrigerant circuit integrity, electrical operation, drainage, indoor airflow, outdoor unit operation, heating and cooling functions, the controls and any abnormal noises.
The question being answered isn’t “does it turn on?” It’s whether the thing operates correctly as an installed system. Plenty of units power up fine while carrying an installation problem that surfaces three weeks later.
Running and testing
With commissioning done, the system gets operated properly. The installer confirms the indoor fan runs, the outdoor unit starts correctly, air is moving, cooling or heating is happening, the drain works, the controls respond, and nothing sounds or feels wrong.
Don’t expect the room to hit its set temperature in two minutes. The point of this stage is confirming correct operation, not proving how fast it cools.
The handover
A decent handover leaves you knowing how to actually use the thing: on and off, switching between heating and cooling, changing temperature, fan settings, timers, the remote, and how to clean the accessible filters.
Sounds trivial. It isn’t. A fair number of “my new air conditioner is faulty” calls turn out to be a remote left in the wrong mode. Five minutes of explanation saves everyone a phone call.
What is a back-to-back installation?
You’ll see the phrase on quotes constantly. It describes the simplest layout — the indoor unit mounted on the inside of an external wall, with the outdoor unit sitting just the other side of it.
Indoor unit → wall → outdoor unit
That usually means short pipework, simple drainage and easy access. The further your job drifts from that arrangement, the more involved it gets.
What makes an installation harder?
Long pipe runs. If the condenser can’t sit near the indoor unit, you’re adding pipework and complexity.
Difficult wall construction. Concrete, double brick or unusual materials change the method.
High or awkward condenser positions. Access drives both time and planning.
Apartments. Balconies, strata rules, common property and building access all come into play.
Difficult drainage. Sometimes there’s simply no easy gravity route from the preferred indoor position.
Electrical work. The existing setup has to suit the proposed system.
Multiple indoor units. A multi-split involves more pipework and considerably more planning than one split.
All of which is why a quote based purely on the capacity printed on the box can be misleading.
How long does it take?
A straightforward single split can often be done within part of a working day. Beyond that, there’s no honest universal figure.
A simple back-to-back bedroom install is a different animal from a high-rise apartment, a long pipe run, difficult concrete walls, restricted condenser access, complex electrical work or a multi-split.
If someone quotes the same installation time for every property without looking at the site, treat the estimate with some scepticism.
Before the installer arrives
Clear the indoor area. Move furniture and belongings away from the proposed wall where you can.
Clear outdoor access. Make sure the condenser area can actually be reached.
Sort building access. For apartments: parking, loading areas, lift bookings, strata working hours, access permissions.
Confirm approvals. Installation morning is a terrible time to discover the owners corporation hasn’t signed off on the condenser position.
Talk through the layout. Make sure you know where the indoor unit sits, where the condenser goes, how the pipework runs and where the water discharges. Changing the plan is free before the drilling starts and expensive afterwards.
What should a finished installation look like?
A good one doesn’t draw attention to itself. Indoor unit sitting straight, outdoor unit securely positioned, sensible pipe routing, tidy external covering where it’s used, no unexplained loose wiring, working drainage, and enough access for someone to service it later.
But don’t judge quality on appearance alone. The work you can’t see — refrigerant preparation, connections, drainage, commissioning — matters just as much. A perfectly level indoor unit doesn’t compensate for a poorly commissioned circuit.
Can I install one myself?
For a normal refrigerant split system in NSW, no. This isn’t a suitable DIY project.
The work involves regulated air-conditioning and refrigeration work plus refrigerant handling. Current NSW rules require the relevant licence or certificate for air-conditioning and refrigeration work, and ARC states that a refrigerant handling licence is required to install pre-charged split-system equipment.
Being confident with a drill doesn’t qualify anyone to open and commission a regulated refrigerant circuit. Different skill, different licence.
How KYNEX Air Conditioning can help
The most valuable part of professional installation happens before the tools come out.
KYNEX Air Conditioning can assess the room, the system capacity, the indoor unit position and the condenser location before installation begins — because the job has to work as one complete system, not a set of separate decisions.
An indoor unit position can look ideal from inside the living room and turn out to be a poor choice because it forces an awkward pipe route or leaves nowhere sensible for condensate to drain. Equally, the easiest condenser spot might give you the worst airflow and no service access.
If you’re planning a new system, KYNEX provides split system air conditioning installation Sydney services for this kind of work. For broader options, see Sydney air conditioning installation.
The benefit is having the whole thing thought through before anything permanent happens.
A realistic example
Say you want a split system in an apartment living room. The preferred wall is beside the balcony, so it sounds simple.
The installer assesses it: indoor unit high on the living-room wall, condenser in an approved balcony position, short pipe route through the external wall, drainage to an appropriate point, electrical supply checked. Straightforward enough.
Now change one thing. There’s no approved space on the balcony for the condenser.
Suddenly you may be looking at a different indoor position, a much longer pipe route, or a completely different installation design.
The air conditioner didn’t change. The building did. That’s what a site assessment is for.
Common mistakes
Choosing the indoor position purely on looks. Airflow and pipe routing count too.
Hiding the condenser in a cramped space. It needs to breathe.
Ignoring drainage. Condensate needs a reliable path out.
Buying the unit before checking installation is feasible. Especially in apartments.
Picking capacity without assessing the room. No installation quality compensates for a badly sized system.
Chasing the cheapest price without reading the scope. Find out what’s actually included.
Forgetting service access. Someone will need to reach both units again — probably sooner than you think.
Frequently asked questions
What happens first? The installer confirms the equipment, indoor and outdoor positions, pipe route, drainage and electrical requirements before any permanent work starts.
Do installers drill through the wall? For most standard installations, yes. The opening lets refrigerant pipework, drainage and cabling connect the two units.
Does a split system need electrical work? Yes. It needs an appropriate supply and connections, and the exact work depends on the equipment and what’s already installed.
What is vacuuming an air conditioner? Evacuation removes unwanted air and moisture from the refrigerant circuit before commissioning, using appropriate equipment. It’s a standard part of proper preparation.
Does the installer add refrigerant? Depends on the equipment, the factory charge, pipe length and the manufacturer’s requirements. Don’t assume every new system needs topping up.
How long does it take? Often part of a day for a simple single split. Difficult access, long pipe runs, apartment conditions or extra work all extend it.
Can I stay home during installation? Usually, yes — the technician just needs clear access to both work areas.
Will it make a mess? Drilling and mounting create dust and debris. A professional job includes reasonable protection and clean-up.
Can a split system go anywhere? No. Indoor airflow, wall construction, condenser position, drainage, pipe routing, electrical requirements and property restrictions all limit the options.
Should it be tested before the installer leaves? Yes. Commissioning and operational checks are part of completing the job, not an optional extra.
The bottom line
A proper split system installation process is a good deal more than hanging two boxes.
Your installer has to work through system suitability, indoor position, outdoor position, wall penetrations, refrigerant pipework, drainage, electrical requirements, refrigerant circuit preparation, commissioning, and the final handover.
When it’s finished it should look simple. That’s usually a sign it went well. But underneath the tidy appearance sits correctly installed pipework, reliable drainage, appropriate electrical work and a properly commissioned refrigerant circuit.
The moment to ask questions is before the first hole gets drilled. Where’s the equipment going? How will the condensate drain? How visible will the pipework be? Can anyone reach it in five years’ time? And is every regulated part of the job being done by someone licensed to do it?
A few careful decisions up front are the difference between an air conditioner that hangs on your wall and one that works properly for the next decade.