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5 things our cooling experts would never do with their air con

Our experts explain why they're big fans of the fan and how cleaning keeps things cool.

child cooling down in front of a pedestal fan
Last updated: 04 January 2024


Checked for accuracy by our qualified fact-checkers and verifiers. Find out more about fact-checking at CHOICE.

With concerns about electricity costs at an all-time high and most parts of Australia already enduring soaring temperatures, there's never been a better time to ensure you're cooling your home as efficiently as possible. 

We asked CHOICE director of reviews and testing Matthew Steen and  Digital Home team lead Denis Gallagher to share their top five air con no-nos.

If you're the type who uses your air con regularly, these tips will help you enjoy the cool without worrying more than you need to about the power bill.

1. They don't overdo it

When stepping outside reminds you of the sensation you get when you open the oven after cooking a roast, it can be tempting to push the air con to the lowest possible temp and luxuriate in the contrasting cold. But if you're making it so chilly that you now need to add a cardigan to your ensemble then you're probably doing it wrong.

"The bigger the difference between the outdoor and indoor temperature, the more it will cost you," says Denis. 

Every degree cooled by more than 8°C will add 10% to your running costs

CHOICE cooling expert Denis Gallagher

"For a reasonable balance of cost and comfort, you should try to keep the temperature difference to around 8°C, so if it's a 32°C day, set your air con to around 24°C " he says.

That doesn't mean you should be sweltering in 37°C when it hits the mid-40s outside, but you do need to consider the implications of that extra cooling on your energy bill and by extension, the environment.

"Every degree cooled by more than 8°C will add 10% to your running costs, which can really add up across the summer," he warns.

woman cleaning filter on air con

A clogged air con filter can increase energy consumption by 5-15%

2. They don't neglect the cleaning

Cleaning is one of those things that makes life easier in the long run if it's tackled in a timely fashion. Leaving the laundry until there are no clean socks is a mistake most of us only make once, but the repercussions of neglecting other types of cleaning can be less obvious. Air conditioners fall into that second category. 

"A lot of people are probably not even aware that they need to clean their air conditioner, and that doesn't simply mean wiping down the outside," says Matthew. 

A clogged filter can increase energy consumption by 5–15%

CHOICE cooling expert Matthew Steen

Opening up the unit to clean the filters and outlet will help your system run more efficiently.

"Regular cleaning and an occasional service will go a long way towards making sure your air con runs well and keeps you cool throughout the summer," he says. 

Staying on top of the cleaning will also help reduce your running costs. 

"It's estimated that a clogged filter can increase energy consumption by 5–15%, so staying on top of the cleaning will also save you money," Matthew says.

3. They don't forget the fans

On a hot day, it can be tempting to hit that air con control straight away, but you may be neglecting a simpler option: the humble fan. 

Fans are not only cheaper to buy they're also effective to run, costing as little as $11 for the whole year. On the other hand, an air conditioner will cost between $40 and $2760 a year to run, depending on the unit size. 

It's true that a tower or pedestal fan won't do as much as an air conditioner but it can help you feel cooler by encouraging the evaporation effect, whereby the movement of air removes sweat from your body, resulting in a drop in your body temperature. Ceiling fans can also help.

"While fans won't actually lower the temperature of the room on their own, they can help keep your body cool down," Denis says. In other words, a fan won't make the room cooler but it will make you feel more comfortable. 

Fans can also be used to enhance the efficacy of your air con.

"A ceiling fan can help move cool air from an air con (installed high) down to the living area (ground level), which can make your room feel cooler," he says.

4. They don't try to cool the whole neighbourhood

When my children were young I seemed to spend most of every hot day in summer reminding them to close doors to keep the cool air in. And we won't talk about the time I found my daughter's bedroom window wide open while the wall-mounted aircon unit struggled valiantly against the 40°C outdoor temperature. 

As a kid, you probably rolled your eyes when your parents nagged you to shut the window and close the door, but it turns out they were right.

You can even use towels to stop gaps under the door

"To keep the cool air in and the hot air out you need to make sure the house is sealed properly," says Matthew.

"Use insulation strips around windows and under doors. Keep unused pet doors shut and close off parts of the house you're not using," he says. 

You can even use towels to stop gaps under the door. When our UK sister organisation, Which? conducted an experiment to compare draught excluders, they found a simple towel outperformed the shop-bought options. Of course, it isn't the neatest solution and you will need to put it back into place each time you open the door but as a cheap and temporary solution, it's definitely effective.

home office with ceiling fan

Using ceiling fans can help move the cool air produced by air conditioner around the room.

5. They don't make the aircon battle the oven

Or the dishwasher, or any of the other home appliances that generate a lot of heat. 

Sometimes you can't avoid using them on a hot day, but there are ways to help reduce the effect they have on your air conditioner's efforts to cool things down.

As well as looking for more energy-efficient appliances when you're buying something new, you can also change the way you run them. 

"Running your dishwasher overnight by either switching it on as you go to bed or using the timer function to delay the cycle means you won't be adding extra heat to the kitchen while you're attempting to cool things down," says Denis. 

"You can also try using a slow cooker or air fryer rather than a conventional oven, as these sorts of appliances won't heat up your kitchen as much as an oven," he says. "Microwaves can be effective for things like steaming vegetables or cooking rice, so you won't have to switch on the cooktop."

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Stock images: Getty, unless otherwise stated.