General information, not technical advice. The label rules and the comparison tool are on the Energy Rating website, linked at the foot of this page.
The label, part by part
The label has four parts worth reading. The plan below shows where each sits, as Energy Rating describes them, and what each tells you.
Top
Output capacity, in kilowatts. How much cooling or heating the unit delivers at a stated outdoor temperature: heating at two temperatures, cooling at one. The higher the kW figure, the more it delivers.
Centre
Star ratings, 1 to 10. They take up most of the label, and they show how much energy the unit uses compared with similar products, for cooling and for heating in each zone.
Right
Energy use, in kilowatt hours a year. Cooling is the top number, in blue; heating sits below it, in red, for each zone.
Bottom left
Noise, in decibels. A house icon gives the noise at full power, with separate inside and outside figures for a split system. Energy Rating says the outdoor figure matters if the unit will sit near a window, a bedroom or a neighbour’s house.
A plan drawn from Energy Rating’s description of the label, not the label itself.
Three zones, three real places
The label’s energy figures come from the hourly temperatures of one real place per zone, and from assumptions about how long a unit runs in each season. Energy Rating publishes them, and they explain why the same unit carries different numbers in each zone.
| Zone | Place it is based on | Cooling season | Hours a year, cooling | Hours a year, heating |
|---|---|---|---|---|
| Hot | Rockhampton | October to May | 2,247 | 277 |
| Average | Richmond, northwest of Sydney | October to April | 840 | 1,921 |
| Cold | Canberra | November to March | 545 | 2,660 |
Energy Rating says the Energy Rating Calculator helps you identify your climate zone. It also suggests which figures to weigh: perhaps only cooling in the hot zone, only heating in the cold zone, and both in the average zone.
These three label zones are separate from the eight climate zones that Your Home uses for designing and building a home, which come from the National Construction Code.
Size first, then stars
Stars only mean something between units of a similar size. Energy Rating puts it plainly: “Star ratings of different cooling capacity or heating capacity models and features cannot be compared.” Its advice is to “choose the size and features you need first, then use the star rating to compare similar models.”
It gives an example. Two units in the hot zone both carry 5 stars, but one is much larger. Even when each is correctly sized for its own space, the larger one uses more electricity and costs more to run, despite the matching stars.
When you line models up, Energy Rating suggests matching them on cooling and heating capacity in kW, on type (reverse cycle or cooling only), on ducted or non-ducted, and on installation type, such as a single split system. One more caution from the general label guide: ratings are reviewed as more efficient models arrive, so the stars on a new model may not compare with those on one bought long ago.
Where you should see the label
- In a shop: it must be displayed on single-phase, non-ducted, unitary or single-split air conditioners up to 30 kW. If you cannot see it, Energy Rating says to check with the retailer before buying.
- Online: showing the label is not mandatory, though Energy Rating says it makes sense for retailers to provide the information.
- Ducted systems: Your Home says some ducted air conditioners provide the label voluntarily.
- Portable units: a single duct portable shows no stars, because Energy Rating says single duct units are not efficient at cooling a room; a double duct portable shows at least half a star for each zone.
What the kilowatt hours are, and are not
The yearly figure is for comparing similar-capacity models. Your actual energy use may differ from it. Energy Rating explains that someone who runs a unit most of the year will likely use more, and someone who switches it on only above 30°C or below 5°C outside will use less; either way, the label still shows how much one model uses relative to another. To turn the figure into dollars with your own tariff, see the setpoint and running costs.
The label answers “how efficient?” only once “how big?” is settled, and sizing a system for a room covers what to look at first. Your Home says the licensed technician who installs the unit can also advise on the right size for your space, so it is a good question to put to an installer before you compare stars.