How to keep cooler for less by using fans with air con

Whether you use a split system, portable or ducted air conditioning to cool a room, the air naturally forms layers at different temperatures. The coolest air sinks to floor level, while warm air rises to the ceiling. Without proper air circulation, this can leave you with uneven temperatures throughout the room, making your air con work harder than necessary.

But surely, air conditioners incorporate fans into them to blow cold air into the room? True. But these in-built fans are designed to direct cooled air into the room rather than to mix the layers of air.

First things first: fans do not cool the air temperature.

Wait, what?! That’s right. You may think you've used fans all your life to lower the air temperature on hot days, but you'd be wrong. What they do, though, is have a cooling effect, which is just as useful in terms of personal comfort.

A ceiling fan set to summer mode (spinning counterclockwise) creates a helpful air movement pattern that:

Running both appliances in tandem has the potential to reduce your energy use and power bills because ceiling fans are significantly cheaper to run than air conditioning systems - especially air con set to more powerful cooling.

Energy costs can vary across Australia and at different times of day, but based on an average energy cost of around 30 cents per kWh, it can cost just a couple of cents per hour to run a 50-75 watt ceiling fan, compared to around 60 cents per hour to run a 2000 watt air conditioner.

Now, consider that every one degree cooler you set your air con can increase the cost of using it by around 5%, according to the CSIRO. Setting it for 23°C at a cost of 60 cents per hour would therefore be more expensive than setting it for 26°C and using the wind-chill effect of a ceiling fan to achieve the additional cooling effect.

Of course, you may be unable to use ceiling fans in the area you want to cool, for a range of reasons. Whether you rent or don’t want to permanently change the look of the room, you might find a portable fan can help achieve a similar, though more targeted, cooling effect to a ceiling fan when used in conjunction with air con.

Pedestal fans are the most common type of traditional freestanding fan and can be good for targeting specific areas, like a home office desk. Likewise, tower fans are easy to move to different spots around your home to boost cooling wherever you may be. Good for narrow spaces, tower fans are often quieter than the fast-moving blades of pedestal fans.