Where 7.1 kW fits
Each model is labelled with its own rated capacity, so you'll come across sizes like 7.1 kW that no room guide mentions. The gap to 7 kW is small. Whether your room sits near the top or the bottom of the range matters far more.
The guides don't agree on that range either. Rinnai's size guide stops 7 kW at 60 square metres, while the CHOICE table that Solar Victoria reproduces gives 60 to 80 square metres a range of 5 to 7 kW.
One big split, or two smaller ones?
The ACT Government's guide says the larger splits can look after areas of up to 80 square metres. One unit on one wall can do it, but in a long or L-shaped room the far end is a long way from the indoor unit.
Two smaller splits spread the air from two points, and on mild days you can run just one. The same guide says a small multi-head system, one outdoor unit feeding several indoor units, can also handle very large rooms. Our multi-split page explains how that works.
A bigger outdoor unit needs a better spot
Ask where the outdoor unit will go before you agree to the size. The ACT guide says to think about access for maintenance, noise reaching the neighbours and fresh air reaching the unit, to avoid enclosed courtyards, and never to box it in with slat fencing.
ActronAir adds that above 35 degrees an air conditioner loses cooling capacity, giving the example of a 14 kW system dropping to 10 or 12 kW. A unit sized with nothing to spare will fall behind on the hottest afternoons.
Warning signs on a quote for a split this size
- A size chosen without anyone measuring the room or asking about the windows.
- An outdoor unit squeezed into a courtyard or hidden behind slats.
- No mention of the power supply. Mitsubishi Electric says the unit needs a dedicated one.
- No second option offered for a long or L-shaped room.
What's yours to check, and what's theirs
You can
- Measure the whole space, corners included, and try it in the size calculator.
- Sketch where an indoor unit could go and how far the air would travel.
Leave to a licensed installer
- A heat load that compares one large unit with two smaller ones.
- Checking the switchboard and running the circuit.
- Refrigerant pipework and commissioning, under an ARC licence.
What we'd do
If it were our living room
We'd ask for the heat load first, then ask the installer to show two options: one 7 kW unit, and two smaller units or a small multi-head. In a long or L-shaped room we'd lean to the pair, because the air doesn't have to cross the whole space to reach you. A split specialist who does big open-plan rooms will know which way yours goes.
