The most efficient split systems for a average climate

It depends on how many hours you run the unit and your electricity price. More stars means less power for the same heating or cooling, and the saving grows with use. Use the running cost calculator with your own numbers, then get up to three local quotes on the models that make the cut.

All three are in the average zone of the Zoned Energy Rating Label. Brisbane and Darwin are in the hot zone, and Canberra, Hobart and Melbourne in the cold zone. The Energy Rating website has the full zone map.

The zoned label rates each model separately for the hot, average and cold zones, and for cooling and heating in each. The unit is the same; the climate it's rated against changes how efficient it is over a year.

Typically $1,400 to $4,800 supplied and installed in 2026, depending on size and the job. 2.0 kW: $1,400 to $2,400; 2.5 kW: $1,500 to $2,500; 3.5 kW: $1,700 to $2,700; 5.0 kW: $2,100 to $3,300. Pipe runs, a new circuit or a second storey add to it. Get up to three local quotes for your actual job.

On the registered indoor sound level, the Samsung AR50F09C1UHN (2.5 kW) is the quietest at 46.9 dB(A). Compare within the same size: bigger units are louder. See the quietest split systems ranking.

For the average climate zone, the AUX CAR3DI (2.6 kW) has the highest cooling rating here at 7 stars. Star ratings on the zoned label run to 10, and a star is worth more in a hot zone than a mild one. For cold-climate heating, the ActronAir WRE-026DS leads at 3.5 stars.

Roughly 2.5 kW for a bedroom, 3.5 kW for a large bedroom or small living room, and 5 to 7.1 kW for open-plan living. West glass and poor insulation push it up. Use the size calculator for your room.