The UK is currently being gripped by an intense heatwave, with a red alert for hot weather in place for over 50 areas this week. When the temperatures are this high, the inside of your car can get extremely hot, which is never pleasant when you first enter.
The first thing people often do when they get into their cars on a hot day is crank up the aircon. However, this might not actually be the quickest or the most efficient way to stay cool. An even better tip was recently shared by the Capital FM presenters as they were discussing heatwave hacks, and there’s even a science behind it.
Presenter Sian Welby brought up the tip which she’d originally seen shared by Professor Hannah Fry on social media, and explained exactly how it worked.
She said: “So you’re in the driver’s seat. You’re going to wind down the window of the back left seat. Then you’re going to get out of your driver’s seat and just open and close the door [four times.]
“You get back in the car, it’s cool.”
It might sound bizarre, but there’s a scientific principle behind this trick called fluid dynamics, according to Hannah. In her own YouTube video, she urged Brits to ditch the car aircon altogether, in favour of this more effective method.
She joked that you may look like ‘a bit of an idiot’ if you start swinging the door open and closed, but it’s worth it in the end.
Hannah explained: “The reason why it works is that when you open and close the door – especially if you do it quickly – the door sweeps out all of the air that’s in its way, creating this area of low pressure that you get here.
“And then that sets up something called bulk flow which is where all the hot, sweaty, horrible air inside the car is drawn outwards.”
Pointing to the open window, she added: “The only way to refill it is with nice, fresh, easy air from over that side.
“It only takes about two or three goes, and suddenly it’s actually beautifully temperate.”
In the video’s comments, people thanked Hannah for her advice with many confirming that it actually did work. One person wrote: “I used to do this without knowing the science behind it– it just seemed like the thing to do and it helps.”
Another said: “Been doing this for 20 years with the blind belief that it’s better than just opening all the windows. Thanks for the scientific pardon.”
And another commented: “This is a top tip, I’ve been doing this for years and can absolutely confirm it works as described.”