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Air conditioning units on a wall

Are our heating and air con habits too selfish?

When you’re feeling the heat at home during a scorching summer, or trying to ward off the winter shivers, it makes perfect sense to crank up the air conditioner or heater.

If you do make a conscious effort to limit your usage, it’s likely your number one priority will be avoiding an expensive energy bill.

But as we become more reliant than ever on air conditioners and heating systems to keep comfortable year-round, it’s worth considering how our habits are harming the environment.

Dr Shama Islam, a lecturer in electrical engineering at Deakin, says when we overdo it on heating and cooling, we increase our carbon dioxide emissions – one of the key factors contributing to global warming.

The higher your carbon footprint, ‘the more it is increasing the temperature of the entire world, increasing the sea levels and also causing very chilly winters in some parts of the world’, Dr Islam says.

So in what is a vicious cycle, the more you use your heating or air conditioning, the cooler or hotter the world will eventually get – leading you to crank up that dial even more.

How your house or apartment affects your energy usage

Anyone who’s ever lived in an old, draughty house will know that some properties require more heating or cooling than others.

Dr Islam says the type of insulation in your home has a huge effect.

‘This is not just for heating; this will also impact your cooling,’ she says.

‘The better insulated it is, the less heat exchange between the outside and inside of the house. So during winter your house is warmer, whereas in summer your house will be cooler because you’re not getting that external heat if you have a good amount of insulation.’

If you’re building a house any time soon, Dr Islam suggests spending a little more on a higher grade of insulation.

But if you’re renting?

In an older house, Dr Islam recommends trying to seal any cracks, especially near windows. ‘Sometimes if you can place your furniture in such a way that it can close those gaps or those cracks, then it might also help you,’ she says.

If possible, Dr Islam suggests opting for a newer house that meets more modern building requirements.

'It is increasing the temperature of the entire world, increasing the sea levels and also causing very chilly winters in some parts of the world.'

Dr Shama Islam,
School of Engineering, Deakin University

Types of heating and cooling

Gas heaters are usually more energy efficient than electric heaters, Dr Islam says.

But if you’re buying a heater, take a close look at the energy star rating first.

Dr Islam says you should also take into account the predicted annual energy consumption, which will be mentioned on the rating sticker.

If you want a single system that can both heat and cool your house, a reverse cycle system is more energy efficient than a constant air volume conditioner that is set to keep your rooms at a certain temperature, Dr Islam says.

‘Why it’s better is that it takes the outside air and uses that to set the temperature to the desired level,’ she says. ‘If you are using the constant air volume conditioners, then they have to always maintain the same temperature, using the air within the house, so it is not as efficient as the reverse cycle system.’

How to use your air conditioner more efficiently

On a hot summer’s day, you might switch on your air conditioner to a low temperature to try and cool things down as quickly as possible.

But Dr Islam says this creates stress on the system.

‘When you suddenly change the temperature set point, the equipment has to work a lot more and has to consume a lot more energy, and thus it creates a greater impact,’ she says.

So you’re better off pre-setting your air conditioner to say, 21 degrees, a few hours earlier in the day, rather than switching it to a lower temperature as you arrive in order to cool things down quickly.

While it may seem counterintuitive to leave your air conditioner on for longer, you’ll actually be using less energy overall with this strategy, Dr Islam says.

Other ideas to lower your energy usage

If you want to save money and energy, take full advantage of the practical methods at your disposal.

For example, rug up in warmer clothing during winter, or only heat or cool the areas of the home you’re using. Think about whether you really need that heater on all night when you’re tucked up warmly in bed.

In summer, close the curtains or blinds early in the day and at night, open all the windows and doors to let the cooler air in. Fans, preferably with a good energy rating, can also help shift the air around.

Of course, if you need to study for long periods, you could also take yourself to the comfort of a local library or café.

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Dr Shama Islam
Dr Shama Islam

Lecturer in Electrical Engineering, School of Engineering, Deakin University

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