With another UK heatwave on the horizon, millions of motorists around the country will be getting familiar with the AC button in their cars again – but it could be costly
03:17, 13 Aug 2025

Brits are set for another heatwave this week as weather maps show temperatures will jump to 34 degrees for parts of the UK. The hot weather will mark the fourth heatwave of the summer so far.
So with the country melting as a result of the heat, it’s a given most motorists will have their air conditioning unit on full blast in the car. With AC on constantly, it can get rather expensive but surely cranking it on high is a no-brainer during a heatwave. Now luckily for you, there is a way to save money as there’s a ‘magic’ air conditioning button you’ll need to familiarise yourself with.
In fact, not only can you benefit during the summer but even use the chilly function all year round.
TikTok user @master_driver666, with a following of 1.4million fans, revealed the secret function for all seasons that you might have missed.
In a video, she demonstrated how this feature comes in handy for winter, wet weather, and even when stuck in traffic. The driver explained how to operate the AC without wasting your fuel.
The clip, captioned “How to use the car’s air conditioning buttons?” went viral, revealing four key functions, including the go-to summer setting which involves engaging the recirculation option to conserve fuel.
When it’s nippy outside, the technique is pretty much the opposite of the summer approach.
During damp, foggy spells, you can run the AC without the recirculation, while hitting the rear de-mister button to swiftly clear any misting.
The TikTok user also highlighted a less obvious tip about using air conditioning during traffic jams, when most motorists would typically wind down their windows.
But with this nifty trick, there’s no need to keep your windows down while stuck in slow-moving traffic.
The post quickly gained traction, amassing roughly 1,200 likes and hundreds of shares. The comments varied from the stunned “Nah this is crazy,” to the curious “Don’t you have to turn off the AC?”