It’s become the go-to advice for dealing with a heatwave: shut your windows and blinds on the hottest days, to avoid heating up your home with hot air coming in from outside.
But energy firm OVO Energy has set out that there’s a lot more nuance to the tip than you might realise, including a strategy for exactly which windows and doors to open and when.
This weekend, many of us will definitely be looking for the best ways to keep a house cool, or how to cool down your house, as the Met Office has forecast a truly sweltering 36C for parts of the UK on Monday, followed by 32C conditions on Tuesday, and the UKHSA has issued heat health alerts for several areas, with humidity also being high, especially in the south of England and London.
One way you can try to cool down your house involves ‘strategic windows and curtains’, closing windows, curtains and blinds that face the sunlight, but opening windows that are still in shade.
In this way, you block hot air from entering, but you let in cooler air at the other end of the house at the same time.
OVO Energy explains: “Creating a cross-breeze through your home on hot, sticky days will help cool things down.
“Choose which windows to open, and when, carefully. Opening windows on opposite walls, or at opposite ends of your home allows air to flow.
“And by opening windows at night and closing them during the day, you’ll trap the cooler air in to circulate. It might seem counter-intuitive, but you can point a fan at an open window, so it pushes the hot air outside.”
But it cautions against opening all the windows, and stresses that south-facing windows in particular should be shut up tight.
OVO adds: “Tempting as it is to fling open the windows at the first sign of summer, it’s not actually the best idea. To keep your house cool, you need to keep the hot air out. This means keeping windows closed during the day – particularly south-facing windows.
“Keep curtains, blinds and windows shut when the sun is shining directly on them, and when you’re out. Try opening windows on the most shaded side of your home, to avoid sunlight and hot air getting in.”
The Met Office said in its latest heatwave forecasts: “The hottest day of the current spell is expected on Monday, with temperatures widely exceeding 30°C in central and eastern England, possibly reaching 34°C in London and towards Cambridge.”