‘Hidden’ window method cools a boiling car in seconds

Getting into a car that’s been sitting in the scorching sunshine all day can be one of the worst parts of a heatwave. But many drivers are unaware their car key may already have a built-in feature that can help cool the vehicle before they get behind the wheel.

It comes after the Met Office issued a red weather warning for heat affecting various parts of the UK over the last week, with the mercury rising as high as 38C. Motorists have been on the lookout for ways to best prepare for their travels, and it turns out it isn’t all too complicated.

Holding down the unlock button on many car keys automatically lowers all of the windows at once. By letting the hot air escape before you even open the door, the inside of the vehicle can begin cooling almost immediately.

The function, also known as ‘global opening’ or ‘convenience opening’, is available on many modern vehicles, although it isn’t fitted to every make or model. Drivers are advised to check their owners’ manuel as some manufacturers require the feature to be activated through the motor’s settings.

It proves particularly useful during periods of hot weather, when the temperature inside a parked vehicle can rise must faster than the air outside. According to the RAC, opening windows and doors before setting off is one of the quickest ways to release built-up heat and improve airflow.

The AA also recommends ventilating a hot vehicle before driving away, rather than relying solely on air conditioning. It says allowing trapped hot air to escape first can make the cooling system more effective, and improve comfort behind the wheel.

Advice comes as parts of the UK continue to experience exceptionally high temperatures. The Met Office says heatwaves can create dangerous conditions inside parked vehicles, where temperatures can become significantly higher than those recorded outside.

While the hidden window feature can help make the car interior more comfortable, it should never be seen as a substitute for proper heat safety. The NHS advises avoiding prolonged periods in hot, enclosed spaces where possible and stresses the importance of staying cool and well hydrated during periods of extreme heat.

Experts also remind motorists never to leave children, older adults or pets inside a parked vehicle, even for a short time. According to the RSPCA, temperatures inside a car can become fatal within minutes, even if a window has been left slightly open.