Motorists across the UK are being cautioned against a hazardous and potentially costly method of de-icing their car windscreens this winter, with experts highlighting a far safer and cheaper alternative using a common household item.
The Dangerous Habit and the Simple Hack
As temperatures plummet, drivers are often tempted to find the quickest way to clear their windscreens. The RAC has issued a stark warning about a dangerous practice from the past. "In the past, people used to boil water in the kettle and then throw it on the frozen car to quickly melt the ice," a spokesperson explained. However, this action can cause 'thermal shock', which will likely crack the glass or, at the very least, weaken it over time, leading to a hefty bill for a replacement windscreen.
In contrast, a savvy motorist named Adrian Garner has shared his effective and economical life hack. Instead of spending around £3 per bottle on commercial de-icer, he recommends using an old spray bottle filled with warm water. "Bit of warm water - not boiling water - in an old bottle. Drip round your car. So much cheaper," he advised on December 28, 2025. The RAC confirms that using lukewarm water can be a viable option when proper de-icer is not available.
How to Use Your Car's Built-in Defrost Systems
After starting your engine, your vehicle offers several powerful tools specifically designed to clear ice safely and effectively. The primary tool is the defrost setting, usually marked with a distinctive symbol and located within easy reach of the driver.
Activating this setting, along with turning the fan to its highest temperature and directing the airflow towards the windscreen and side windows, will systematically melt the ice. It is crucial to clear both the front and rear screens for maximum visibility. Many modern cars also feature:
- Heated rear windows with thin mesh wires that heat up rapidly.
- Heated wing mirrors to clear crucial reflective surfaces.
- Heated front windscreens on some higher-spec models.
Key Takeaways for Frosty Mornings
The consensus from motoring experts is clear: patience and the correct methods are vital. While pouring boiling water is a fast option, the risk of thermal shock and a cracked windscreen makes it a terrible habit. A simple bottle of warm water provides a safer, low-cost stopgap.
Ultimately, the built-in defrost and heating systems in your car are designed for this exact purpose and will not damage the glass. Taking an extra minute to use these systems properly is a small price to pay compared to the cost and inconvenience of a windscreen replacement.
