What the registry data actually shows
Cooling capacity is the fair way to compare the two, since a "big" portable and a "small" split can claim the same room size. Filtering the July 2026 energyrating.gov.au snapshot to units rated between 2.0 and 3.8 kW of cooling output, the bracket most bedroom and small living-room units are sold into whether portable or split, gives 771 split systems against 376 portables. The split systems draw a registry median of 0.60 kW to do that cooling. The portables draw 1.00 kW to produce the exact same cooling output: 67% more electricity for the same job.
What this costs, state by state
Both types rated at the same 2.0-3.8 kW cooling output; only the box around the compressor changes. Running 6 hours a day at each type's registry-median draw.
| State | Rate | Split system | Portable |
|---|---|---|---|
| New South Wales | 32.4¢ | $1.17 | $1.94 |
| Victoria | 29.8¢ | $1.07 | $1.79 |
| Queensland | 31.2¢ | $1.12 | $1.87 |
| South Australia | 38.1¢ | $1.37 | $2.29 |
| Western Australia | 33.6¢ | $1.21 | $2.02 |
| Tasmania | 28.9¢ | $1.04 | $1.73 |
| Australian Capital Territory | 27.4¢ | 99¢ | $1.64 |
| Northern Territory | 31.7¢ | $1.14 | $1.90 |
Reference rates for 2026–27. Your row is highlighted once you set your location.
Why the box changes the bill
A split system dumps the heat it pulls out of the room straight outside through the unit bolted to your wall. A portable has to do the same job with the compressor sitting inside the room it's cooling, venting hot exhaust air out through a flexible duct taped into a window gap. That duct wastes cooling capacity two ways: the compressor itself now warms the room it's meant to be cooling, and cheaper single-hose models pull replacement air back in through gaps around the window seal, which is often warm outside air the unit then has to cool all over again. It's the same reason our aircon running cost calculator uses a lower registry-median draw for every split-system size than a portable of the same rated output.
None of this makes a portable a bad buy. Renters without approval to drill a wall for a split system, and anyone cooling one room for a few weeks over summer rather than a whole season, are trading a higher running cost for zero installation cost and the ability to take it with them when they move.
Try it with your own hours
The table above prices a full 6-hour evening. Set your own hours and state below and watch the cheaper side get the stamp.
Common questions
Is a dual-hose portable more efficient than a single-hose one?
Yes, meaningfully. A dual-hose portable draws its replacement air from outside instead of pulling warm room air back in through the window gap, which is the main reason single-hose units run hotter and less efficiently for the same rated cooling output.
Does a portable cost less to run if I only use it for a few weeks?
No, the hourly rate stays the same either way. A portable still draws about 67% more power per hour than an equivalent split, whether you run it for three weeks or three months. What short-term use changes is the total: six hours a day for three weeks on the NSW reference rate comes to about $16 more than a split doing the same job over the same period, which is cheap next to the cost of installing and later removing a split system.
Is it cheaper to leave a portable air conditioner on all day?
No, for the same reason it isn't cheaper for a split system: there's no efficiency reward for cooling a room nobody's in. See our companion guide on whether it's cheaper to leave the aircon on all day for the state-by-state numbers, which run even higher on a portable given its higher draw.
Sources
Electricity rates: AER Default Market Offer and each state's regulated reference tariff, current for 2026–27. Appliance draw: the energyrating.gov.au registration database (July 2026 snapshot). Cooling behaviour and setpoint advice: energy.gov.au, Summer energy savings.