What happens on aircon installation day, step by step

A split-unit installation involves more steps than just mounting a box on the wall and running a pipe outside. Knowing the sequence helps you spot whether a crew is working properly, and gives you a reasonable idea of how long to expect the visit to take.

If you have not booked yet, installation specialists on this directory are ranked using real customer feedback on workmanship and reliability, which is worth a look before the day arrives. The home page lists every provider category on this directory in case you are also comparing a repair or servicing job at the same time.

Before the crew arrives

A good installer will usually confirm a few things in advance: the unit model and capacity, where the indoor and outdoor units will sit, and the pipe route between them. If this conversation has not happened by the time the crew shows up, it is worth asking about it on arrival rather than assuming they will figure it out on the spot.

The installation sequence

1. Site assessment. The technician confirms wall type, checks for hidden wiring or plumbing, and marks where brackets and the wall sleeve for piping will go.
2. Indoor unit bracket mounting. The mounting bracket is leveled and fixed to the wall, which the indoor unit will later hang from.
3. Wall drilling. A hole is drilled through the wall for the piping, drainage, and wiring to pass through to the outdoor unit.
4. Outdoor unit placement. The condenser is mounted on a wall bracket or ground stand, positioned with enough airflow clearance to run efficiently.
5. Piping, wiring and drainage connected. Refrigerant piping, electrical wiring, and the condensate drain line are run and connected between the two units.
6. Vacuum and pressure test. The system is vacuumed to remove air and moisture, then pressure tested to check for leaks before refrigerant is released into the lines.
7. Power on and test run. The unit is switched on and run for a period to confirm it cools properly and the drain is clearing water correctly.
8. Clean-up and walkthrough. Debris from drilling is cleared, and the technician should walk you through the remote control and basic settings.

What separates a rushed job from a proper one

Step	Rushed job	Proper job
Vacuum test	Skipped or shortened	Full vacuum held and checked
Piping finish	Left loose or unsealed at wall entry	Sealed and neatly routed
Bracket levelling	Eyeballed	Checked with a level
Drain slope	Not checked	Confirmed to drain away properly
Test run	Powered on briefly	Run long enough to confirm steady cooling

The vacuum and pressure test is the step most likely to be skipped when a crew is rushing, and it is also the one most likely to cause problems later, since trapped air or moisture in the lines reduces cooling efficiency and can lead to a refrigerant leak within the first few months.

After the crew leaves

Run the unit for a full day or two and pay attention to how evenly it cools, whether it is unusually loud, and whether any water appears near the indoor unit, which would point to a drainage issue. A small number of customers report installation defects like reverse wiring or piping leaks turning up after the fact, which is exactly why the initial test run and a follow-up check within the first week or two matter. Most installers will come back to correct a defect found early at no charge, since it falls under workmanship warranty rather than a separate repair.

For anything that feels off, whether it is noise, uneven cooling, or a smell, contacting the installer directly within the first week is usually faster to resolve than waiting until the next scheduled service.

Multiple units on the same day

Installing several units in one visit follows the same sequence for each, but crews often stagger the work: mounting brackets across all rooms first, then piping, then testing each unit in turn once everything is connected. This is a reasonable way to work through a full-house installation, and it is worth confirming that every unit gets its own vacuum and pressure test rather than one shared check at the end, since each system’s piping run is different. If you are still comparing providers before booking, the aircon installation cost guide covers typical pricing by unit size and what changes it.

Details on how workmanship and reliability feedback shape provider rankings on this directory are on the methodology page.