Hot tips to reduce the cost of electricity bills over summer
Hot tips to reduce the cost of electricity bills over summer
28 February, 2022
Summer in Australia is about children running through sprinklers, blocking your ears from the cacophony of cicadas, and flipping to the cool side of your pillow on a hot night.
But with above-average temperatures expected through the season, it's also becoming a time to sweat over the power bill that comes after keeping the house cool.
Electricity costs have skyrocketed in recent years and although they may have stabilised for the moment, "we're not foreseeing energy prices to fall anytime soon", says Ian Swain, Energy Efficiency Council acting head of projects.
Want to avoid the post-summer bill shock? Here are some hot tips from cooling and sustainability experts to help reduce your electricity during the heat.
1. Avoid setting your air conditioner too cool
very degree lower you set your air conditioner could be adding 10 per cent more to your power bills, says Mr Swain, who specialises in environmental science and sustainability.
He says setting the thermostat to 25 degrees Celsius is the optimal temperature to balance comfort and cost.
"Twenty-six degrees is really the limit of thermal comfort for most people," he says.
He also reminds people of the importance of dressing sensibly in air-conditioned environments.
"What you want to avoid is running your air conditioner down low, like 20 or 21 degrees, and getting around the house in tracksuit pants."
In some locations electricity peak usage rates are getting up around 50 cents per kilowatt hour (kWh).
So using a 5kW air conditioner will cost around $2.50 to run each hour, says Jianlei Niu, a professor of building, environment and energy at the University of Sydney.
An air conditioning engineer by training, Professor Niu says our increasing reliance on the appliances brings more than just financial costs.
"Here in Australia we have witnessed several outages of electricity supply due to the concentrated use of air conditioning."
2. Close your windows and doors during the hottest hours
If your first thought on a hot day is to open up the house for some ventilation, you may want to first check the outside air temperature.
"The temperature on an extreme day … heats up your walls and furniture," Professor Niu says.
"So the idea is to circulate the air when the air is cool outside. When it is really getting hot you try to avoid this."
He advises using fans and air conditioning to cool yourself first.
In areas of relatively low humidity, this could be combined with using spray water bottles or placing damp towels on your skin.
"The water evaporation cools down the air because it changes into a vapour," Professor Niu explains.
Once the outside temperature is lower than inside, opening the windows and doors and cross-ventilating the house becomes a sensible option.
For two-storey buildings, Professor Niu says it's important to open both the downstairs and upstairs areas.
"The cold air will get in from the ground floor, while the warm will get out from the upper floor," he says. "That is the natural way of air circulation when there is no wind."
3. Give the fans a good spin
Turning on an upright or ceiling fan can use less than 10 per cent of the energy needed for air conditioning, says human thermal comfort specialist Dr Richard Aynsley of the Sunshine Coast.
"If your main intention is to economise on cooling, you've got serious problems in Australia because we've got the largest homes in the world," Dr Aynsley says.
"Cooling the person is a fraction of what it would cost to cool the entire house or even one room."
He suggests we look back to a time when individual desk fans were common in office environments before the widespread use of air conditioning.
"In the tropics the fans are put under the desks, so it won't disturb the loose paper on top," he says.
"But they must have fine control of the speed of air, because people are very sensitive of the airflow across their bodies."
4. Block out the sunlight and insulate
Drawing blinds and curtains are obvious ways for keeping the sun out from a room.
But if the sun is striking directly on your windows, you get a lot of short-wave radiation that enters the house and becomes heat, explains Dr Swain.
"From the inside you'll reflect a bit of sun back out through the window, but you've already let a lot of it in," he says.
"So a golden rule is to try to stop the sun striking any windows — so it's always better to shade from the outside than from the inside."
He advises installing adjustable awning blinds and shade sails that will also allow you to control the direct light entering the home during the colder months.
Mr Swain says that most Australian homes could probably do with more ceiling insulation, and a viable option for renters could be to draught-proof the gaps between window and door openings.
"For $100 spent down at your local hardware store, it can yield a lot of useful improvements and they're not difficult to do."
He also says roof ventilators are useful for drawing hot air out of attic spaces, which can easily exceed 50 degrees on warmer days.
"In winter that warmth could actually be valuable, so it's a bit of a trade-off depending on where you live."
5. Make the switch to LED lighting
LED (light-emitting diode) lights use about 75 per cent less energy than halogen light bulbs.
They also last 5-10 times longer, according to the Department of Environment and Energy.
"If you've got a house with a lot of halogen downlights, you can actually feel the heat from those and it's not what you need on a hot summer's night," Mr Swain says.
"You get a double benefit with LED lights: not only do they use much less energy but they're a lot cooler."
The Australian Government's Energy Rating lighting app can help you choose the right type of light globes to use around your home.
6. Check your plumbing and pooling
Hot water heaters consume a fifth of household energy, and older electrical systems may also be running at peak times of the day when power costs the most.
"Licensed electricians can install timers which will turn off your hot water system so it's not drawing power at the most expensive time of the day," Mr Swain says.
The backyard pool can also be a major drain on a home's energy use.
"You might want to talk to your local swimming pool shop about ways you can optimise your energy use, particularly if you're using older pumps — you can save energy by putting timers on," he says.
"You've just got to be careful to balance that with the health requirements."