Choosing a reverse cycle air conditioner in Melbourne: the factors that matter
A reverse cycle air conditioner is a heat pump for your air: one machine that cools in January and heats in July, and in Melbourne it is the cheapest way to heat a home, typically a third of the running cost of the gas heater it replaces. Here is how to choose one.
Size to the room, honestly
Rough Melbourne guidance: about 1.2 to 1.5kW of capacity per 10 square metres for a standard-height insulated room, more for big windows, poor insulation or south-facing rooms. A 20 square metre bedroom wants roughly 2.5kW; a 40 to 50 square metre open living area wants 6 to 8kW.
Both errors cost you. Undersized units run flat out, wear early and still miss the setpoint on a 40 degree day. Oversized units cost more, cycle on and off, and dehumidify poorly. An installer who quotes without asking room sizes, window sizes and insulation is guessing with your money.
Read both sides of the star label
Australian zoned energy labels rate cooling AND heating, and the map zones matter: Melbourne sits in the cold zone, so judge the heating stars for our climate specifically. A unit that looks great on cooling stars can be mediocre at 5 degree heating, which is the workload Melbourne actually gives it. More stars translate directly into decades of lower bills.
Inverter technology and cold performance
Every decent modern unit is inverter-driven, meaning the compressor ramps smoothly instead of switching on and off. What separates brands is behaviour at low temperatures: check the rated heating capacity at 2 degrees, not just the headline number measured at 7. Established Japanese brands hold their capacity in the cold notably well, which is why they dominate the premium tier.
Noise, inside and out
Indoor units range from a library-quiet 19dB on low to an intrusive 45dB or more. The outdoor unit matters for bedrooms and neighbours, especially in townhouse settings where councils and owners corporations have rules. Both figures are on the datasheet; check them before the unit is on the wall, not after.
Splits, multi-splits and ducted
Single splits (one outdoor, one indoor unit) are the value workhorses and the right answer room by room. Multi-splits run several indoor units off one outdoor unit where wall space is tight. Ducted systems heat and cool the whole house invisibly at two to four times the price, and zoning is what makes their running costs sane. Many Melbourne homes do best with two or three well-placed splits rather than one ducted system.
Installation quality is half the product
Refrigerant lines run properly, condensate drained correctly, the outdoor unit mounted where it can breathe, and the electrical work licensed: a mediocre unit installed well beats a premium unit installed badly. VEU discounts apply to some efficient units too, with the same advice as hot water: take the rebate, but buy the appliance on its merits.
Figures and guidance last checked 31 August 2026.