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A hot summer puts real pressure on a household’s energy use, and the households that come out the other side with a manageable bill are usually the ones who did a little preparation before the heat properly set in. None of this requires expensive upgrades. It is mostly about getting your cooling system ready, stopping heat from building up inside the house in the first place, and using appliances a bit more sensibly once the temperature climbs.
Check your cooling system before the heat arrives
Whatever you rely on to stay cool, whether that is a split system air conditioner, ceiling fans, or a combination of both, it is worth giving it attention before the first real heatwave rather than during it.
- Clean or replace air conditioner filters. A clogged filter forces the unit to work harder and use more energy for less cooling.
- Check outdoor units are clear of leaves, dust and overgrown plants so air can flow properly.
- Give ceiling fans a wipe down. A dusty fan blade is less efficient and can also flick dust into the room once it is running at speed.
- If your system has felt weaker than usual over the past year, or is getting old, book a service call before summer rather than waiting until it fails on the hottest day.
Stop heat from building up inside the house
Keeping heat out is generally more effective, and cheaper, than trying to cool a house down once it has already heated up.
- Close curtains, blinds or shutters on the sun-facing side of the house during the day, especially on windows that get direct afternoon sun.
- Check for gaps around doors and windows. Draught seals that stop cold air escaping in winter also stop hot air pushing its way in during summer.
- Where you can, use external shading such as awnings, blinds or shade cloth. Blocking sun before it hits the glass is far more effective than trying to block it once it is already inside the room.
- Open windows for cross-ventilation in the cooler parts of the early morning or late evening, then close everything up again once the outside temperature climbs past the inside temperature.
Use fans and air conditioning together, not one or the other
Ceiling and pedestal fans do not lower the actual air temperature, but the airflow makes a room feel several degrees cooler, which means you can often run an air conditioner at a slightly higher, more efficient temperature setting while a fan does some of the work. It is generally more efficient to set an air conditioner to a reasonable temperature, such as the mid-twenties, and let it run steadily, rather than setting it very low and having it cycle on and off constantly.
Try to cool only the rooms you are actually using. Closing doors to unused bedrooms or spare rooms means the system is not working to cool space nobody is in.
Be mindful of hot water and appliance use
Hot water systems and major appliances also affect a summer power bill, just less obviously than air conditioning.
- Where your hot water system allows it, running it during off-peak periods can reduce cost, though this depends on your tariff and system type, so it is worth checking what applies to your household.
- On very hot days, using the oven adds heat to the kitchen that your cooling system then has to work to remove. Cooktop meals, the microwave, or an outdoor barbecue keep that heat outside where it belongs.
- Run dishwashers and washing machines with full loads rather than half loads, and where possible during the cooler parts of the day.
Small habits that add up over summer
A few consistent habits make a genuine difference over a whole season, even though none of them feel significant on their own:
- Turn off exhaust fans once they have done their job. Left running, they pull cooled air straight back outside.
- Keep fridge and freezer seals in good condition and avoid leaving doors open longer than necessary.
- Unplug or switch off appliances at the wall when they are not in use, particularly anything that runs warm even on standby.
- Keep an eye on your bill or usage app early in summer so you can spot a sharp increase and investigate it while it is still a small problem.
When it is worth calling in help
If your cooling system genuinely cannot keep up even after basic maintenance, or your bills jump sharply despite reasonable habits, it is worth getting a professional opinion rather than guessing. An inefficient or ageing system, poor insulation, or gaps you cannot easily find yourself are all things a qualified technician or energy assessor can identify properly.
For a deeper look at how a home’s orientation, ventilation and shading affect summer comfort and running costs, particularly relevant if you are in Queensland, see our related article on keeping a Queensland home cool.
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