Expert settles debate over whether you keep windows open or closed during heatwave

Although summer was a bit of a wash out, the UK is currently experiencing a bit of late season sunshine with the warmer temperatures set to stick around for a few days.

And with the country in the midst of a mini-heatwave, you may be wondering how to keep your house cool and whether popping open a window will help bring in a breeze or simply allow warmer air inside.

But wonder no longer because a couple of experts have answered the age-old question once and for all.

Doctor Andrew Shea, a senior lecturer in building physics in the University of Bath’s department of architecture and civil engineering, told the Guardian that despite what you may think, it’s actually a bad idea to open your windows if you’re hoping to cool things down.

“If it’s cooler inside than outside, you should keep your windows closed,” he said.

Opening up the window will just allow for warm air to enter, in most cases, meaning your home will actually heat up - not cool down.

He added: “If you have a shaded area at the back of the house, for example, you might be able to open a window there – but generally, you don’t want to open the windows. Just grab on to that last bit of cool air inside.”

Pexels/Thirdman

Doctor Ana Souto, a principal lecturer at Nottingham Trent University’s school of architecture, design and built environment, agreed.

She told the Guardian: “Close everything. You can open the windows late in the evening and early in the morning – until 9am or so – when it’s cool, but otherwise keep them closed. My place is like a cave, but it works.”

For anyone who is struggling with the heat, there’s a simple trick you can do with a fan that will help.

All it involves is spinning your fan around 180 degrees to face into an open window.

So the fan should face outwards and shouldn't be blowing directly at you.

Pexels/Samson Katt

The idea is championed by New Zealand-based eco-design adviser Nelson Lebo, who apparently became aware of the trick when his grandmother would do it in the 1970s.

He explained: "Everyone knows about cross-ventilation, but it only works when the wind is blowing and then it works best when there is a direct route for the wind to blow through a home.

"What the fan does is, it forces cross ventilation, even when the wind is not blowing. A fan will also pull air around corners, as in our home.

"The overall goal is to pull the warm air out while drawing cool air in once the outdoor temperature drops below the indoor temperature. Fans use hardly any power compared to AC."

So there you go.