As temperatures rise across the UK, motorists are being warned that a widespread summer habit could be putting windscreens at risk of cracking. New research from Autoglass® highlights a significant “summer blind spot” among UK drivers, with millions unaware that extreme heat combined with sudden cooling can turn a small chip into a costly crack.
With a heatwave pushing temperatures above 30°C in parts of the country, experts say that everyday actions inside a hot vehicle may be unintentionally increasing the risk of windscreen damage through a process known as thermal shock.
New data from Autoglass® reveals that over half of UK drivers (52%) admit their first instinct when entering a hot car is to switch the air conditioning straight to its coldest setting. While this may feel like the quickest way to cool down, experts warn it can rapidly cool the windscreen surface while the rest of the glass remains hot, increasing stress within the material and potentially worsening existing chips.
Despite this risk, more than 60% of drivers surveyed were unaware that blasting cold air conditioning in a hot vehicle could damage a windscreen. The findings highlight a clear knowledge gap, particularly at a time when millions are expected to travel during peak summer conditions.
The research also suggests that many motorists are delaying or avoiding essential repairs. Nearly a third (32%) of drivers said they would simply “hope for the best” and continue a summer journey even if they noticed a small chip before setting off. A further 15% admitted they would not take action because a minor chip does not concern them, while 9% said they would attempt DIY fixes such as PVC glue, plasters, or tape rather than seeking professional repair.
Debra Christoforou, Marketing Manager at Autoglass®, said: “Our research shows a worrying gap in driver awareness, with over 60% of motorists not realising that blasting cold air-conditioning on a hot day can cause damage to their windscreen. Sudden changes in temperature cause the glass to expand and contract rapidly, and this ‘thermal shock’ can cause a small chip to turn into a crack.
“With temperatures set to soar over 30 degrees this week, and the Met Office warning of more heatwaves over the next three months, millions of these drivers will be hitting the UK roads. Every driver should take just a couple of minutes to check their windscreen before setting off on any summer journeys to prevent an unnecessary, heat-related repair headache.
“What many people don’t realise is that a windscreen chip repair can cost as little as ten pounds, and is sometimes even free, depending on their insurance company and glass cover. Repairing a chip is a quicker, more cost-effective, and sustainable option than a full replacement, so acting early can help save both time and money.”
Experts also point to basic preventative steps that can reduce the risk of thermal shock and windscreen damage. One of the simplest methods is to avoid immediately switching air conditioning to its coldest setting when entering a hot car. Instead, drivers are advised to open windows first to allow trapped hot air to escape naturally, then gradually introduce cooler air, ensuring vents are not directed straight at the windscreen.
Parking habits can also make a significant difference. Leaving a vehicle in shaded areas or using a windscreen sunshade helps reduce internal temperatures and limits sudden stress on the glass surface, particularly where small chips already exist.
Drivers are also being urged to avoid makeshift DIY repairs. Quick fixes such as tape, plasters, or PVC glue do not properly seal windscreen damage and may reduce the effectiveness of later professional repairs, potentially leading to more expensive work in the long run.
Ultimately, professionals emphasise that early intervention is the most effective approach. A small chip repair is typically quick, affordable, and far more sustainable than a full windscreen replacement, which takes longer and costs significantly more. Motorists are encouraged to check their windscreens before any journey, however short, to avoid preventable summer damage.
