How do I read the zoned label?
Mitsubishi Electric's explainer covers the main parts. The blue stars rate cooling and the red stars rate heating. Rinnai says the scale runs from 1 to 10 stars, based on independent testing.
The label also shows how much energy the unit uses each year for cooling and for heating, and the lower that figure, the less it should cost to run. Two noise figures give the sound power of the indoor and outdoor units, and lower means quieter.
The example label in the ACT Government's guide shows cooling capacity at an outdoor temperature of 35 degrees, and heating capacity at 7 and at 2 degrees. If winters are cold where you live, the 2 degree heating figure is the one to look at closely.
Which climate zone am I in?
| Cities on the label's map | What to look at first | |
|---|---|---|
| Hot zone | Brisbane, Darwin | Blue cooling stars |
| Average zone | Adelaide, Perth, Sydney | Blue and red, as both get used |
| Cold zone | Canberra, Hobart, Melbourne | Red heating stars, and heating capacity at 2 degrees |
That's the grouping on the example label in the ACT guide. If you live somewhere in between, the federal Energy Rating calculator fills in your climate from your postcode.
Comparing two models fairly
Compare like with like. The ACT guide says the most meaningful comparison is between systems of similar capacity in kW, and that the rating depends on where the unit will be installed.
Don't compare old labels with new ones. Mitsubishi Electric says star ratings on the old label and the zoned label shouldn't be compared, so a high star count on a unit from before 2020 tells you little about a new one.
Spec sheets use two more terms. ActronAir defines EER (energy efficiency ratio) as how effectively a unit cools, and COP (coefficient of performance) as its heating efficiency. The ACT guide puts COP in practical terms: a CoP of 6 uses half the energy of a CoP of 3 for the same heat.
System type matters too. The ACT guide's excellent CoP figures are 6.4 for splits, 5.1 for multi-heads and 5.0 for ducted.
What about ducted systems?
Ducted units are the awkward case. The government sources we've checked don't agree on whether ducted systems have to carry the zoned label, so a ducted model may or may not show stars. Ask the installer for the maker's published heating and cooling efficiency, and look the model up on the Energy Rating website.
What else makes a unit efficient in your home
The right size comes first. The federal Energy Rating calculator calls choosing a suitably sized unit the first, and most important, step.
Age counts. By Solar Victoria's reckoning in its 2021 guide, a unit past 15 years typically burns through more than three times the energy a modern reverse cycle one needs.
So does how you run it. The Energy Rating calculator suggests 18 to 20 degrees in winter and 25 to 27 in summer, and says each degree past that could add 10% to your bill. Daikin says a clean filter in place of a blocked one can lower energy use by 5% to 15%.
Stars carry legal weight in Victorian rentals. From 1 March 2027, where the rental rules call for an energy efficient heater or cooler, a non-ducted unit needs at least 2 heating stars to count as the heater, and at least 3 cooling stars to count as the cooler. See our rental rules guide.
Ask before you buy
- How many stars does it have for our zone, for heating and for cooling?
- What's the rated input power in each mode?
- What heating capacity does it have at 2 degrees?
- Can you show me this model on the Energy Rating site?
- If it's ducted, what efficiency figures does the maker publish?
What you can check yourself
You can
- Look up models on the Energy Rating calculator, which takes your postcode and lets you enter your own tariff.
- Estimate running costs with input power times hours times your rate, or use our running cost tool.
- Keep the filters clean and the outdoor unit clear.
- Set the thermostat within the ranges above.
Leave to a licensed installer
- Working out the size from a heat load.
- Telling you whether an old system is worth replacing.
- Insulating the ducts properly on a ducted job.
- Setting up zones and controls.
What we'd do
Where we'd start
Settle the size first, with a heat load from an installer. Then, among units of that size, choose the one with the most stars in your zone for the job that matters most where you live: red stars in Melbourne or Canberra, blue in Brisbane or Darwin. Ignore any star claim from the old label, and ask the installer to show you the model's listing before you sign.
