How to Choose a Split-System Air Conditioner

For most Australian homes, the real question isn’t whether to get a split system — it’s sizing, installation, and whether you’re even allowed to install one where you live. Split-system reverse-cycle air conditioning is the realistic default across most of the country, not an aspirational upgrade, and this guide is about getting that decision right rather than convincing you it’s the right category in the first place.

Sizing: the part most guides get vague about

Split systems are rated in kW of cooling capacity, and the temptation is to just buy the biggest one that fits the budget. That’s the wrong instinct — an oversized unit cools the room too fast to properly remove humidity, then cycles on and off repeatedly, which is both less comfortable and less efficient than a correctly sized one running steadily.

As a rough starting range:

Room type	Typical capacity
Single bedroom	2.5–3.5kW
Living area or open-plan space	5–7kW+
Whole small home (multi-split or ducted)	Installer-quoted, based on total floor area

This is a starting point, not a substitute for actually sizing it — ceiling height, insulation quality, window size, and how much direct afternoon sun the room gets all shift the real number. Use our room-size calculator for a proper range before buying.

Installation is a separate job, and it isn’t optional

Unlike a portable unit you plug in yourself, a split system’s outdoor and indoor units are connected by refrigerant lines that legally require a licensed technician to install — this is a genuine legal requirement in Australia, not just a recommendation. Budget for installation as a separate cost on top of the unit price, and get quotes from at least two or three installers rather than assuming the cheapest hardware plus a random installer is the best total price.

This guide is general information to help you compare options — always use a licensed technician for the actual installation, and see our disclaimer for the full picture.

A rebate may cover part of it, depending on your state

Several Australian states run rebate schemes for high-efficiency reverse-cycle systems — Victoria and the ACT have confirmed, active schemes worth several thousand dollars for larger ducted replacements; NSW and South Australia have active schemes too, though the amount varies; and some states currently have nothing dedicated to this. It’s genuinely worth checking before you get quotes, since an accredited provider applies the discount upfront rather than something you claim back later. See our full state-by-state breakdown or the quicker rebate checker for your specific state.

If you’re renting

This is where a split system stops being a simple buying decision. Fixed air conditioning in a rental usually needs written landlord consent, and in an apartment building, often owners corporation (strata) approval as well before any installation work starts. A landlord generally can’t unreasonably refuse consent for a change like this, and most states have a tenancy tribunal you can escalate an unreasonable refusal to — but it’s worth being clear-eyed about the starting position: landlords in Australia aren’t legally required to provide air conditioning at all, so installing one as a tenant is a request you’re making, not something you’re owed.

If that approval process isn’t realistic for your situation — a short lease, an uncooperative landlord, a strata building that says no — a portable air conditioner is the practical fallback with none of that approval overhead. Our bedroom cooling guide covers how portable stacks up against a split system in more detail, and if you’re in a dry climate specifically, our evaporative cooling guide covers the other realistic alternative.

What actually differs between similarly-sized units

Once you’re comparing two units at the same kW rating, the real differences are usually:

• Smart/app control — genuinely useful if you want to turn it on before you get home, less useful if you’ll only ever use the wall remote.
• Noise rating at the indoor unit — worth checking specifically if it’s going in a bedroom, the same consideration as our bedroom cooling guide covers for other cooling types.
• Warranty length and local parts/servicing network — an established brand with a long local service history matters more over a 10+ year appliance lifespan than it does in year one.
• Review volume, not just star rating — a 4.7★ rating from 50 reviews is more evidence than the same rating from two, even for a well-regarded brand.