What happens on split system installation day?

A smooth install day starts at the quote. By then the capacity should be matched to the room, the indoor head's position agreed, the outdoor unit's spot chosen with airflow and neighbours in mind, and the route for pipe, drain and cable worked out. The switchboard should have been checked for room for a new circuit.

If anything has changed since, such as new furniture, a different room or a fence going in where the outdoor unit was to sit, mention it before the day. Moving a head by a metre is easy on paper and harder once the hole is drilled.

Someone needs to be home at the start to confirm positions and at the end for the handover. In between, expect drilling noise, doors open while pipes and cables go through, and the power off for part of the job while the circuit is connected.

If the fridge, a home office or medical equipment can't lose power, say so beforehand so the shutdown can be planned around it.

The installer fixes a mounting plate level on the wall, then drills a hole for the pipe, drain and cable. The hole slopes slightly down to the outside so water drains out rather than back into the room, and the head hangs on the plate with the pipes passing through behind it.

Outside, the copper refrigerant pipes, condensate drain and interconnecting cable run to the outdoor unit, usually inside a cover along the wall. The drain needs a steady fall the whole way, or a condensate pump where it can't fall. The outdoor unit goes on a wall bracket or ground pad, level, with clear space for airflow and service.

In Victoria, refrigerated air-conditioning work is a class of plumbing work regulated by the Building and Plumbing Commission, and installing a split system needs a refrigerant handling licence. It's reasonable to ask who will do each part of the job.

Most split systems need a dedicated circuit from the switchboard. Energy Safe Victoria guidance says that where the manufacturer's specifications require a dedicated circuit or safety switch protection, they must be followed. The electrician runs the new cable, fits the circuit's protection at the board and connects the outdoor unit and the cable to the head.

The Wiring Rules require air conditioners with a compressor to have a lockable isolating switch next to the unit but not on it, so you'll see a new isolator beside the outdoor unit. Energy Safe Victoria lists air conditioning as non-prescribed electrical work: the electrician completes a Certificate of Electrical Safety and must give you a copy within 30 days.

Before the refrigerant held in the outdoor unit is released into the pipes, the installer pressure tests the joints, commonly with dry nitrogen, to confirm there are no leaks. A vacuum pump then draws air and moisture out of the pipework. Moisture left inside can harm the compressor and performance, so a proper vacuum takes time and is checked on a gauge.

Once the vacuum holds, the valves are opened and the system started. Commissioning means running it in cooling and heating, checking the air temperature at the head, confirming the drain flows outside and listening for vibration. Wall penetrations are then sealed inside and out.

Handover is your chance to ask questions. You should be shown how to set modes and timers, how to remove and clean the filters, where the isolator is, and which paperwork to keep with the manual.