KEY POINTS
- Every extra degree of cooling will increase your air conditioner’s energy consumption by 5–10%.
- The best air conditioner’s temperature for cooling in summer is between 22–24℃.
- The best air conditioner temperature for heating in winter is between 19–21°C.
What temperature does your air conditioner usually run on and how much is that costing you? Can small changes to your air conditioning habits actually save you money?
In this article, Canstar Blue looks at the ideal air conditioner temperatures for your home, as well as how much your air conditioner use could be adding to your electricity bill.
On this page:
- What is the best air conditioner temperature to save energy?
- What is the best temperature to set your air conditioner to in summer in Australia?
- What is the best air conditioner temperature for sleeping?
- What is the best temperature to set your air conditioner to in winter in Australia?
- How do temperature settings affect air conditioner costs?
- Annual cost of air conditioner cooling temperature settings
- Annual cost of air conditioner heating temperature settings
- What is the right-sized air conditioner for your home?
- Why does air conditioner temperature matter?
- Other ways to save on air conditioner usage costs
- Compare cheap electricity deals
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What is the best air conditioner temperature to save energy?
The optimal temperature for air conditioners will vary between the summer cooling and winter heating periods and will be affected by the type of air conditioner you have, its energy efficiency or star rating and what type of climate you live in.
What is the best temperature to set your air conditioner to in summer in Australia?
Depending on your state and region, a standard air conditioner’s temperature should be set between 22–24℃ for cooling in summer.
According to the Department of Climate Change, Energy, the Environment and Water every extra degree of cooling will increase energy consumption by 5–10%. So as a guide, Daikin recommends setting your air conditioner in summer to eight degrees below the outdoor temperature.
If you live in the sub-tropical climate of North Queensland or the Northern Territory, setting your aircon to 22–25°C will help reduce your energy usage costs in summer. For milder climates, such as Tasmania, a summer air conditioner temperature of 28°C is sufficient.
What is the best air conditioner temperature for sleeping?
While this topic is subjective for each person, Simply Air suggests optimal sleeping temperature is around 18°C for adults, and slightly higher for babies.
Other ways to maintain a good sleeping temperature is to look for light and breathable nightwear and bedding during summer, and warmer blankets and pajamas in winter. Optimising bedwear and bed linens for the climate will contribute to a more comfortable sleep and hopefully less reliance on air conditioning at night.
What is the best temperature to set your air conditioner to in winter in Australia?
While it may vary depending on your location, you should generally set your air conditioner temperature to between 19–21°C for heating in winter. Fujitsu, a leading air conditioning manufacturer, claims that this ensures maximum energy efficiency from your unit.
If you live further south, you’ll likely need to set your aircon at the higher end of the winter heating spectrum. Homes in Central Australia can set their air conditioner as low as 17°C, while households in Southern Victoria and Tasmania can aim for 20–21°C in winter.
Note: it’s important to know how to set your air conditioner’s temperature for heating and other functions.
How do temperature settings affect air conditioner costs?
Energy bills can increase when air conditioner cooling temperatures are set too low during summer and heating temperatures are too high in winter. This is because the harder the air conditioner has to work, the more electricity it will consume, which can sometimes lead to bill shock.
It is difficult to pinpoint how much air conditioner temperature settings contribute to electricity usage costs. However, Ergon Energy estimates that every one degree cooler in summer adds around 10% to the amount of electricity that the air conditioner uses. Using the Ergon air conditioner cost calculator, you can see how small changes to the cooling temperature you set your air conditioner can make a considerable difference to its cost.
Annual cost of air conditioner cooling temperature settings
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| Cooling capacity | 21° | 22° | 23° | 24° |
|---|---|---|---|---|
| 2.5kW | $67.61 | $61.86 | $54.66 | $50.35 |
| 3.5kW | $113.07 | $103.45 | $91.42 | $84.20 |
| 5.0kW | $176.02 | $161.04 | $142.32 | $131.08 |
| 6.0kW | $216.82 | $198.37 | $175.30 | $161.46 |
| 7.1kW | $254.12 | $232.50 | $205.46 | $189.24 |
| 8.0kW | $289.09 | $264.49 | $233.74 | $215.28 |
| 10kW | $378.85 | $346.61 | $306.31 | $282.13 |
| 14kW | $582.85 | $533.25 | $471.24 | $434.04 |
Source: Ergon Energy Air Conditioning Calculator – 17/04/2025. Assumes 34.069c/kWh electricity usage rate (Tariff 11 – Ergon Energy network) with air conditioner running four hours a day for 13 weeks of the year. General guide only.
Annual cost of air conditioner heating temperature settings
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Central heating annual costs
| Air conditioner type | Small house (100m²) | Medium house (160m²) | Large house (220m²) |
|---|---|---|---|
| Multi-split reverse-cycle 1.5 star rating | $770 | $1,232 | $1,694 |
| Multi-split reverse-cycle 2.5 star rating | $513 | $924 | $1,271 |
| Ducted reverse-cycle (unzoned) 1 star | $1,155 | $1,848 | $2,542 |
| Ducted reverse-cycle (unzoned) 2.5 star | $722 | $1,320 | $1,815 |
Source: sustainability.vic.gov.au. Calculations are based on an electricity tariff of 29.3c/kWh (peak) and 21.6c/kWh (off-peak). Approximate annual energy costs are based on an average pre-existing 2005 house in a Melbourne climate, heating to 20˚C.
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Reverse-cycle air conditioner
| Rating | Annual energy costs | |
|---|---|---|
| Small room (12m²) | 2 stars | $98 |
| 3.5 stars | $69 | |
| Medium room (30m²) | 1.5 stars | $287 |
| 3 stars | $191 | |
| Large room (60m²) | 1.5 stars | $574 |
| 3 stars | $383 |
Source: sustainability.vic.gov.au. Calculations are based on an electricity tariff of 29.3c/kWh (peak) and 21.6c/kWh (off-peak). Approximate annual energy costs are based on an average pre-existing 2005 house in a Melbourne climate, heating to 20˚C.
What is the right-sized air conditioner for your home?
According to the Good Guys, 2.6kW of power is needed to cool a 10m2 to 20m2 room with standard-height ceilings. The higher the ceiling, the more powerful the air conditioner unit needs to be.
If a room is larger than the air conditioner was designed for, the unit will be less effective at controlling the temperature. Air conditioner remotes might be set to cool to 24°C, but the room’s temperature might actually be 28°C. If your room is too small for the air conditioner, it will cool the room quickly then shut off. An air conditioner that turns on and off can use more energy and potentially cause a larger-than-necessary energy bill.
Below is an approximate guide to ideal air conditioner capacities given the room size.
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| Room size m2 | Cooling capacity (C) / heating capacity (H) |
|---|---|
| 9m2 | 2.5kW(C)/3.2kW(H) |
| 25m2 | 3.5kW(C)/3.7KW – 4.3kW (H) |
| 30m2 | 3.5kW(C)/3.7KW(H) – 5.0kW(C)/6.0kW(H) |
| 40m2 | 5.0kW(C)/6.0kW(H) – 6.0kW(C)/7.2kW(H) |
| 45m2 | 6.0kW(C)/7.2kW(H) – 7.1kW(C)/8.0kW(H) |
| 50m2 | 7.1kW(C)/8.0kW(H) – 8.0kW(C)/9.0kW(H) |
| 55m2 | 8.0kW(C)/9.0kW(H) – 9.2kW(C)/10.0kW(H) |
Source: Air Conditioner Buying Guide, Harvey Norman. General guide only.
The ceiling height of the area you’re heating or cooling can change the heating or cooling capacity of your air conditioner. The higher the ceiling, the more powerful an air conditioner you will need. If you’re unsure about what size air conditioner you need, seek a professional quote.
Why does air conditioner temperature matter?
Finding the compromise between being comfortable and being frugal can be a challenge at first, especially at night during summer. Applying some of the advice in this article might help save you some time and guide you towards avoiding inflated energy bills.
Other ways to save on air conditioner usage costs
- Sealing and insulation: If the space you’re trying to heat or cool is poorly sealed or insulated, your air conditioner will have to work harder to reach the temperature you have set (i.e. if you’re trying to cool your home down to 24°C, you may have to set your air conditioner’s temperature to 20°C)
- Energy efficiency: An air conditioner will be labelled with two separate star ratings. The blue star rating shows the air conditioner’s cooling efficiency rating, while the orange one shows heating efficiency
- Alternatives to air conditioning: Ceiling fans, tower fans and pedestal fans have considerably lower running costs than air conditioners. Also consider if solar air conditioning could be right for you
- Maintain your air conditioning unit/s: If you find that your home isn’t being cooled or heated properly, your air conditioner may need to be serviced. There may be coil blockages or dirty filtration, causing the unit to work harder
- Use the air conditioner’s functions
- The timer can be utilised to ensure that the air conditioner is only being used when someone is at home
- The dehumidifier mode is handy during periods of high humidity in summer and can help remove the moisture from the air instead of turning the degrees on the unit down. This is particularly useful in subtropical climates
For more ideas on cooling your house down while avoiding high electricity costs, check out Canstar Blue’s 10 tips to cool a house down without air conditioning.
Compare cheap electricity deals
As the seasons change, it’s a good idea to assess your current energy plan and review the usage rates you are being charged. Minimising usage rates will also help minimise air conditioner running costs, among running costs of other home appliances.
Regularly comparing your energy plan with the cheapest on the electricity market is a great way to avoid being charged the default market offer (DMO), which tends to be more expensive than other plans.
Canstar Blue has made it easier to compare providers by listing some of the cheapest deals in each state below.
Here are some of the cheapest published deals from the retailers on our database that include a link to the retailer’s website for further details. These are products from referral partners†. These costs are based on the Ausgrid network in Sydney but prices may vary depending on your circumstances. This comparison assumes general energy usage of 3900kWh/year for a residential customer on a single rate tariff. Please use our comparison tool for a specific comparison in your area. Our database may not cover all deals in your area. As always, check all details of any plan directly with the retailer before making a purchase decision. Here are some of the cheapest published deals from the retailers on our database that include a link to the retailer’s website for further details. These are products from referral partners†. These costs are based on the Citipower network in Melbourne but prices may vary depending on your circumstances. This comparison assumes general energy usage of 4000kWh/year for a residential customer on a single rate tariff. Please use our comparison tool for a specific comparison in your area. Our database may not cover all deals in your area. As always, check all details of any plan directly with the retailer before making a purchase decision. Here are some of the cheapest published deals from the retailers on our database that include a link to the retailer’s website for further details. These are products from referral partners†. These costs are based on the Energex network in Brisbane but prices may vary depending on your circumstances. This comparison assumes general energy usage of 4600kWh/year for a residential customer on a single rate tariff. Please use our comparison tool for a specific comparison in your area. Our database may not cover all deals in your area. As always, check all details of any plan directly with the retailer before making a purchase decision. Here are some of the cheapest published deals from the retailers on our database that include a link to the retailer’s website for further details. These are products from referral partners†. These costs are based on the SA Power network in Adelaide but prices may vary depending on your circumstances. This comparison assumes general energy usage of 4000kWh/year for a residential customer on a single rate tariff. Please use our comparison tool for a specific comparison in your area. Our database may not cover all deals in your area. As always, check all details of any plan directly with the retailer before making a purchase decision.
Original reporting by Simon Downes
Image Source: Yuri Hoyda/Shutterstock
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