General information, not financial or medical advice. In extreme heat, health comes before savings: see cooling in a heatwave.
What official pages suggest for the dial
The national pages agree on the summer range. Pages from New South Wales and two network operators give slightly different figures, so each row below stays with its own source and place.
| Source | Where it applies | Summer cooling | Winter heating | Each degree |
|---|---|---|---|---|
| Your Home | Australia | 25 to 27°C | 18 to 20°C | about 5 to 10% more energy |
| energy.gov.au, guide for renters | Australia | 25 to 27°C | 18 to 20°C | 5 to 10% more energy |
| NSW Climate and Energy Action | New South Wales | 23 to 26°C | 18 to 21°C | about 10% off the cooling bill for each degree higher |
| Energex | Queensland network | 25°C | 18°C | around 10% more per degree cooler |
| United Energy, high heat safety | Victorian network | around 24°C | not given | not given |
Your Home’s passive cooling page puts the same idea another way: set the thermostat to the warmest setting that still feels comfortable.
A fan lets the dial sit higher
Your Home suggests combining fans with air conditioning, which gives the same comfort at a higher thermostat setting, ideally 25 to 27°C in summer; it says the savings from running the air conditioner less more than offset the cost of the fan. energy.gov.au says fans cost much less to run than air conditioners. Your Home also cites evidence from Darwin, Brisbane and Sydney that ceiling fans can reduce air conditioning use by up to 75%.
Habits the official pages name
- Close doors to rooms you do not need to cool.
- On a very hot day, turn the air conditioner on before it gets really hot; it won’t have to work as hard while the outside air is cooler.
- Use timers, sensors and controls to cut the hours it runs, and turn it off when you go out.
- Close windows, curtains, blinds and doors in the hottest part of the day.
- Seal gaps and cracks that let air leak; energy.gov.au calls it a cheap way to cut your energy bill by up to 25%.
- With a ducted system, remember the ducts: leaky or poorly insulated ones waste energy and lose cool air.
- Keep the space above an outdoor compressor clear so air can flow, and consider shade, which can make overheating less likely.
Why it matters: Your Home says heating and cooling together use the largest share of energy in the average Australian home, around 40 per cent.
Working out a running cost
Energy Rating sets out the sum like this:
“Annual running cost = Total energy use for cooling and heating (kWh) × Electricity tariff (dollars per kWh)”
- Find the yearly kilowatt hours for your climate zone on the unit’s label: cooling is the blue top number, heating the red one.
- Find your tariff in the service calculation section of your electricity bill.
- Multiply the two.
Energy Rating’s own illustration, as published when read on 8 October 2026: a reverse cycle split in the hot zone with an estimated 2,254 kWh a year, at an example tariff of $0.4659 per kWh, gives an estimated $1,050.14 a year. The tariff there is Energy Rating’s example, not a current price; use the figure on your own bill.
Treat the answer as a comparison, not a forecast. Energy Rating says your actual energy use may vary from the label’s figure, and its buying tips list what moves it: how you use the appliance, where you live, your tariff, and whether you have solar.
When it is dangerously hot
The settings above are about saving energy. In hot weather, NSW Health’s advice is to use air conditioning if available to keep a comfortable temperature indoors, and it notes that once it reaches about 39 degrees or more, fans may do less to keep someone cool. Cooling in a heatwave has the signs of heat illness and the first aid.
The label and the bill give you a fair comparison between models. energy.gov.au suggests asking a licensed technician for tips on where to place a unit and how to run it in the most efficient and cost-effective way, which is a good question for a licensed installer before the unit goes in.