What shapes an install in Perth
Cooling first, heating second
Perth Metro's January and February mean maximums are 31.4 and 31.7 degrees, and its July mean minimum is 8.1. NCC 2016 calls it climate zone 5, warm temperate. Size for summer, but don't leave the heating side to chance.
Coast or inland
A home near Gosnells (33.0 degrees in January, on average) carries a bigger summer load than one near Swanbourne (29.8). Mitsubishi Electric lists climate and orientation among the inputs to a heat load calculation, one more reason a quote should follow a visit.
Mostly detached houses
77.8% of Greater Perth's occupied dwellings were separate houses at the 2021 Census, so ducted and multi-room installs are realistic for most. If you're among the 7.6% in a flat or apartment, check with the strata before booking anyone.
Gas, solar and power
ATCO's gas network covers the metro area, and about 36% of SWIS customers have rooftop solar. Mitsubishi Electric says a new unit needs its own dedicated power supply, so expect the switchboard to be part of the quote.
Evaporative or reverse cycle for a Perth home?
| Evaporative | Reverse cycle | |
|---|---|---|
| Seasons | Cooling only | Cooling and heating |
| Windows | Some left open while it runs (Seeley) | Closed while it runs (Seeley) |
| Best conditions | Hot, dry, low humidity (CHOICE) | More flexible in humid, coastal and mixed weather (Seeley) |
| Connections | Water supply, power and a drain | Refrigerant pipes, power and a condensate drain |
| Where it sits | A roof unit over a duct opening | An outdoor unit on the ground, a wall bracket or a roof frame |
How a Perth install usually runs
A visit, not a phone guess
The installer looks at the rooms, the roof space, the switchboard and where outdoor equipment can go, then works the size out from a heat load.
A written quote
Model and capacity, where each unit goes, what's included, who's doing the electrical work, and the Refrigerant Trading Authorisation number (starting AU) the ARC requires on quotes.
Install day
Units mounted, ducts or pipework run and drains set. On reverse cycle, the refrigerant circuit is leak-tested before the system starts.
The electrical connection
In WA the switchboard protective device and fixed wiring are electrical installing work, done by a licensed electrician employed by a licensed electrical contractor.
Handover
You're shown the controls and the filters, and you keep the quote, invoice and warranty papers together.
Why WA watches who installs
In May 2025 the WA Government reported that a business owner was fined after facilitating two split system installs in 2024 and invoicing for them under his business name, without ever holding an electrical contractor's licence. In WA it's an offence to do electrical installing work, or imply you're authorised to, without one.
That's why we're careful about our role. We don't install or invoice anything. Licence-checked installers who specialise in your kind of install see the job, and the one who takes it gets your contact details, then quotes and contracts with you directly.
WA Consumer Protection also says that inviting a quote doesn't stop a deal made on that visit from being unsolicited, and during the cooling-off period the business can't take payment. If you're pressed to sign at the kitchen table, read our cooling-off guide first. The job in general is on our air conditioning installation page.
Your part, and the installer's
You can
- Decide whether you want heating from the same system. It narrows the choice straight away.
- Note which rooms get the afternoon sun and which you use at night.
- Photograph the switchboard and the outside walls before anyone visits.
- Look up the EC number and ARC licence before you sign.
Leave to a licensed installer
- The heat load and the final size.
- Roof work, ducts, refrigerant pipework and leak testing.
- The switchboard and fixed wiring, under a licensed electrical contractor.
- Taking out an old system and recovering its refrigerant.
What we'd do
Where we'd start
We'd answer the winter question before anything else. If you want heating from the same system, go reverse cycle. If you're inland, like fresh air through the house and already have heating sorted, get an evaporative quote alongside it. Then we'd make sure whoever quotes does that system every week, check the EC and RTA numbers on the quote, and never sign on the first visit under pressure.
