25-07-2025
Expert reveals the best temperature to set your AC during a heatwave — and it might surprise you
With another heatwave predicted for the weekend, things are hotting up. While it's tempting to escape inside and crank up your AC to stay cool, it's neither energy-efficient nor cost-effective.
To save you from losing your cool and facing a rocketing energy bill, we asked HVAC experts what the ideal temperature is to set your AC during a heatwave.
Your first instinct might be to turn down the thermostat to pump out more cold air, but this is the wrong approach. Not only does it send your energy bill skyrocketing, but it's also not energy-efficient.
Rather than constantly yo-yoing with your thermostat, a consistent temperature is the best approach. The U.S. Department of Energy suggests setting your AC to 78°F (26°C) when you're at home during the day and to 74°F (23°C) while you're asleep.
While you may want to bring your indoor temperature down further, to say, 72°F, Tara Energy explains what impact this will have on your energy consumption and bill, 'Because AC units require so much energy, and outdoor summer temperatures tend to be much hotter than 72°F, it takes a lot of energy to bring indoor temperatures down to this level.'
The Energy Protection Agency's ENERGY STAR program recommends using a programmable thermostat to adjust your home's temperature at times when you're regularly away or sleeping. Apart from saving you from constantly changing the setting, it will ensure you are not using energy unnecessarily.
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There are also other measures you can take to prepare your AC for a heatwave and keep it in good working order, ensuring it remains efficient. The EPA recommends changing the AC's air filter regularly to prevent dust and dirt from accumulating in the system. It suggests replacing the filter every month, especially during the winter and summer months when use tends to be heavier.
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It also recommends maintaining proper upkeep with a qualified HVAC technician to prevent future problems.
Another option to stay cool in a heatwave is to use the 'dry'mode on your AC unit, if it offers this feature. Day says, 'Humid conditions can make the air feel heavier and more uncomfortable than the temperature alone would suggest. Dry mode doesn't cool as aggressively as standard cooling, but by removing excess moisture from the air, it can significantly enhance comfort levels while using less energy.'
And he concludes, 'Air conditioning should be about creating comfort, not a freezer-like environment, and striking that balance will keep your home pleasant without pushing the unit (or your electricity bill) to breaking point.'
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