As the UK braces itself for a heatwave, many people will be wondering whether they should keep their windows open or closed to stay cool
The Met Office has warned a return to heatwave conditions is “increasingly likely” with temperature set to soar into the 30s this week. After last month’s record-breaking hot weather which saw temperatures peak at a sweltering 37.7C, conditions have quickly settled and returned to normal.
But forecasters say this respite may be brief, with high pressure from the Azores poised to push temperatures up again as early as this weekend.
As many people will be struggling with the heat our thought turns to opening windows.
The trusty fan remains a dependable option, although it does have certain limitations. But what about fresh air? When it’s sweltering outside, should you leave your windows open or closed?
To clarify this timeless debate, we spoke with seven specialists. And while their answers differed marginally, they all reached essentially the same verdict.
What the specialists said
The overall agreement was that windows shouldn’t remain open constantly. Interior trends specialist at Tapi Carpets and Floors, Johanna Constantinou, described leaving them open as a major mistake.
Johanna explained: “During a heatwave, one of the biggest mistakes people make is having all the windows open during the hottest part of the day.
“In most homes, it’s actually far more effective to keep windows, curtains and blinds closed from late morning through to early evening to stop warm air and direct sunlight building up indoors. Then, once temperatures drop in the evening, open windows strategically on opposite sides of the home to create cross ventilation and let cooler air circulate naturally.”
This guidance was supported by Martyn Bridges, Director of External Affairs at Worcester Bosch, who said: “During a heatwave, people should generally keep windows closed during the hottest parts of the day, particularly in rooms exposed to direct sunlight.
“Blinds or curtains should also be kept closed during the day to help block out direct sunlight and prevent rooms from becoming too hot. This helps reduce solar gain, where the sun warms the home and causes indoor temperatures to rise.”
Determining whether to keep windows open or shut is essential, particularly for those trying to get some kip at night or working from home during daylight hours.
On this subject, Vitality Health’s Dr Katie Tryon explained: “There are several things you can do to help yourself stay cool at night. Firstly, it’s important to keep your bedroom cool. Drawing curtains and blinds during the day and keeping windows closed if in direct sunlight to stop hot air getting in can help. When night comes and the air gets cooler, leaving the window ajar to let a cool breeze in can also make it easier to sleep.”
When it comes to getting proper rest, though, it’s critical not to depend entirely on fans or open windows, with Dr Punam Krishnan, working alongside Stannah, warning that physical preparation was just as important as ventilation.
She said: “While methods such as opening windows and using electric fans to cool your room’s temperature are widely recognised, it’s important to also focus on cooling down your body, as well as your surroundings, to maintain a high sleep quality during the summer months.”
This guidance against leaving windows open continuously was supported by Hillarys product expert Victoria Robinson, who stated: “There are several things you can do to help yourself stay cool at night. Firstly, it’s important to keep your bedroom cool.
“Drawing curtains and blinds during the day and keeping windows closed if in direct sunlight to stop hot air getting in can help. When night comes and the air gets cooler, leaving the window ajar to let a cool breeze in can also make it easier to sleep.”
Victoria suggested opening windows on opposing sides of your property during the evening instead of throughout the day, which generates what is referred to as a cross-breeze, permitting air to circulate freely through the space.
She said: “Once temperatures start to drop in the evening, that’s the best time to open windows and allow cooler air to circulate through your home. Creating a cross-breeze by opening windows on opposite sides of the house can help cool rooms down more quickly.”
Reach Plc also approached the University of Derby to secure their opinion on the subject. Professor Chris Sansom, an authority in renewable energy storage, advised that adopting a strategic approach was one solution.
He explained: “Give thought to the windows in your house that you’re opening. For example, opening windows on the opposite sides of your home can create a much-needed, cooling cross-breeze.
“For even better results, try opening your windows at night-time and closing them during the day to trap cooler air inside and keep it circulating. During daylight hours, open windows on the shaded side of your home to reduce the amount of heat and sunlight entering your home.”
There’s also another compelling reason to avoid leaving all your windows wide open — security. The Perspicacity Life’s Craig Andres warned: “Temperatures are set to soar over the bank holiday weekend and while it’s tempting for households to leave windows open, it’s important not to overlook home security.
“Simple security mistakes such as leaving keys in locks or within reach of open windows, leaving doors unlocked, or windows ajar create easy opportunities for burglars, and more than a quarter of summer burglaries are linked to these oversights.”
Verdict
So, whether it’s boosting your quality of sleep, keeping a comfortable temperature, or simply safeguarding your home, it’s arguably wiser to avoid leaving windows open round the clock. Come nightfall, though, opening windows on both sides of your property to generate a cross-breeze can prove a highly effective method of cooling things down.