Every Aussie knows how scorching it gets in summer, and air conditioning is an absolute must. But with rising energy prices, turning on the AC has never been so expensive, so it’s important to know how much it will cost you to do so.
In this article, we break down exactly how much it costs to run an air conditioner in Australia, based on the two most common rooms that you want to cool, and some typically-sized systems.
Cost to run air conditioner by room
The two main areas where you’ll typically run air conditioning are your bedroom and living areas. Here are the costs for both.
Sleep is absolutely crucial for our health. Having the AC on at night time can be the difference between a good night’s sleep, and a terrible one (check out our article on the best temperature for sleeping for more info).
The typical size for a small bedroom is 3m by 3m. This sized room would require a 2kW air conditioner to provide the necessary cooling without being overloaded. For a 2kW Daikin air conditioner, the machine has a typical power input cooling rating of 0.45kw. Based on the current power cost of 25 cents per kWh (in Queensland), the 2kw Daikin air conditioner will cost around 12 cents per hour at full load. “Full load” means that the machine is running at maximum capacity until the temperature setting is achieved (e.g. 24 degrees, or perhaps cooler if you get hot during the night).
After the air conditioner reaches the set temperature, the unit will then utilise its inverter system to maintain the set temperature, which minimises energy use. The inverter essentially works by controlling the speed of the system’s compressor, so that it doesn’t have to constantly work “full whack” as older machines did. When the outside temperature drops at night, the unit will often use around half the rated power to maintain its temperature (e.g. around 50 cents per night).
If we use an example of a bedroom about twice the size, this larger bedroom will require twice the power usage (e.g. $1 per night). A really useful tip is to take the heat out of the room before you go to bed using the air conditioner, then switch to using a ceiling fan while you sleep, which only uses around $0.01 to $0.02 per hour. The lowest cost combination is to combine the use of your air conditioner with your ceiling fan—double power, but with less cost!
Essentially, cooling your bedroom with an air conditioner is extremely cost efficient. And as we mentioned above, a good night’s sleep is 100% worth it.
Living areas are where you spend most of your time at home, so this is another important place for air conditioning. These typically include your lounge/living room and kitchen, which also happen to be the largest areas of your home.
Living areas do vary in size, but on average, we can assume that an 8m x 5m area (40 sqm), would require a 6kW unit. A Daikin 6kW air conditioner has a power input rating of 1.69kW (cooling capacity). If we base our assumptions on an energy cost of 25c per kW/hr, this means that our 6kW air conditioner would cost around $1.50 per/hr when working at full load. Again, the aircon unit only runs at full load until the target temperature is achieved, before switching to the inverter for temperature maintenance. During this maintenance phase, the air con unit only needs to run a half its power rating (depending on the outside temperature and insulation cooling loss rates), so is likely to only be costing around $0.75 per hour. If you looked at a larger living space, for example 60 sqm, you could assume the unit would use 1.5 times the power and cost around $2.25 per/hr at full load and $1.12 per/hr in maintenance mode.
Again, combining the use of your air conditioner with a ceiling fan will cut these costs dramatically because the greater the air flow in the room, the cooler you will feel (in theory, we all know that a lone fan doesn’t cut it on humid Queensland days). If you assume that you use your living area for around 5 hours a day, then the average living room (40 sqm) would cost around $4.50 per day to cool, and much less if you combine the AC with a ceiling fan.
Compare the costs of running your AC
What typical day-to-day costs does running your AC compare to?
- A cup of coffee from a cafe = $4.50. This comes to about a full week of air conditioning for your bedroom, with the system running 8 hours a night.
- A cafe breakfast for 2 = $45. Around a week’s worth of living room air conditioning, with the system running for 5 hours a day.
- A tank of petrol $120 = Over a month’s worth of living room area conditioning.
These costs will be even less if you use your ceiling fan alongside the air conditioner. Running AC is so much cheaper than you might think.
How to reduce average cost of running AC
While running your AC is already very reasonable given the benefits of staying cool, reducing your energy costs will leave more in your bank account, and also helps to reduce your carbon footprint. Here are our top 10 tips for reducing the average running costs of your AC.
1. Insulate your roof
If your roof isn’t well insulated, a lot of cool air will escape from it (and hot air during winter). Make sure that the roof is up-to-spec with the latest insulation standards for your state. In Queensland, it’s recommended to use insulation with a thermal rating of between R2.5 and R4.1.
2. Seal your doors and windows
Your doors and windows are another common escape route for air, so properly sealing them will really help you to keep hot air out, and cool air in. This can have substantial effects on your AC’s energy usage.
3. Keep your curtains and blinds closed
Our sun produces about 2 billion atomic bombs worth of energy per second, and a tiny portion of that energy comes streaming in through your windows. You can keep key rooms much cooler by simply closing their curtains and blinds, which blocks some of the energy and keeps it outside.
4. Install whirlybirds and eave vents
Whirlybirds are an excellent way to ventilate your roof and keep fresh air flowing through, which cools it down in the process. Eave vents work in a similar way, and either are a good option for reducing your AC energy bills. Plus, seeing a pigeon spin around on a whirlybird is hilarious.
5. Set a timer on your AC
You can set a timer on your AC so that it automatically shuts off at a certain point. Once a room is cool, it can stay that way for hours (depending on the outside temperature), so this is a fantastic way to reduce your running costs. All modern air conditioners should have this timer function.
6. Get the heat out of the house prior to using the air conditioner
Before you turn on your AC, open all of your windows and doors to let the heat out and let in fresh air. You can turn ceiling fans on too, to speed up the process. Once the hot air is removed, then turn on the air conditioner. It won’t have to work anywhere near as hard to bring the temperature down.
7. Turn on the AC early
If the forecast is for a very hot day and the house is going to be occupied during the day, turn on the air conditioning early and set the temperature one degree higher than normal (say 25 degrees). The air conditioner will easily reach the set temperature and maintain it during the day.
8. Clean your air filters
Your air conditioner’s filters can quickly become clogged with dust and dirt, and the system needs to work harder to push air through them. Be sure to regularly clean the filters to prevent this from happening. You can find instructions in our article on how to clean your air conditioner.
9. Connect your air conditioner to Tariff 33
Tariff 33 is an economy tariff that has reduced energy costs (approximately 30% less). You can ask your energy supplier whether they offer this tariff, and then connect your air conditioner to it. This can be done in rooms that are not being used at times of peak electricity demand (approx. 5.30pm to 8.30pm) e.g. bedrooms.
10. Turn off unused zones
If you have a ducted air conditioner, be sure to turn off any zones that you aren’t using. The more zones that are active, the more space is being cooled, and the higher your electricity costs will be.
Note: these recommendations are guidelines only. The above running costs are only guidelines. Each house will vary due to many factors, some of which are:
- Type of ceiling insulation
- Size of windows facing west
- Size of eaves and awnings
- Prevailing breezes
- Pitch of the roof
- Whirly birds and eave vents fitted
- Natalie Silver, 2019, Best Temperature to Sleep: Research and Sleep Tips, Healthline