As the UK braces for a chilly blast, many are turning to trusty hot water bottles for comfort. With temperatures plummeting to a bone-chilling -20C in some areas, staying warm is a top priority.

Echoing Money Saving Expert Martin Lewis’ cost-effective tip to ‘heat the human, not the home’, hot water bottles have become a popular choice. They’re not only budget-friendly but also an efficient way to keep cosy, whether you’re working with one on your lap or snuggling up with it in bed.

However, safety should never be compromised for warmth. A lesser-known fact about hot water bottles that has come to light is the presence of a hidden symbol indicating their safety for use.

Over time, hot water bottles can deteriorate; they may crack, leak, or even burst, leading to serious injuries or burns. Generally, these bottles are safe to use for around two years before they start posing risks.

Consumer experts at Which? took to TikTok to issue an warning urging users to regularly check their hot water bottles. A consumer expert said: “According to The Children’s Burns Trust, if yours is more than two years old, then it’s too old. To make sure, you can check your bottle’s date of manufacture. Just look out for this handy daisy wheel symbol.”

The expert highlighted the importance of the daisy wheel symbol, often found on the neck or body of your bottle, which you might need to uncover by removing any sleeve. “The central number is the year the bottle was made, and if you want to be more specific, the petals represent the 12 months of the year, and the dots are the weeks in those months,” he explained.

Before using your water bottle, it’s crucial to check for any signs of wear and tear. “And if you’re buying a replacement, look out for the symbol to make sure you really are getting something brand new,” he advised.

The Children’s Burns Trust also recommends that only adults should fill bottles, holding them upright by the neck and using cooled boiled water from the kettle, suggesting a five-minute wait before filling. Bottles should be filled to a maximum of two-thirds and the stopper must be tightly secured.

To avoid burns, never place a hot water bottle directly against your skin and always use a cover.