With the winter in full swing, most people are now using their heating, but a simple mistake could lead to costing them a lot of money. It’s reported UK households are being hit with eye-watering repair bills over winter and, according to insurance expert Matt Durrant from i4me, a surprisingly common heating mistake is behind the worst of the damage, and you’ll want to avoid it in January. 

Matt says loft water tanks often freeze or overflow during cold snaps. “It’s a perfect storm,” Matt explained. “When a ballcock valve in a loft tank fails, water can flow continuously. If the tank freezes, it can split or overflow, and the water doesn’t trickle. It cascades through the house.”

In older or period properties with decorative ceilings, it’s not uncommon for claims from these incidents to exceed £75,000, making them some of the costliest winter insurance cases in the UK. It’s not the only heating mistake that can lead to wasting a lot of money either. 

Why loft insulation makes the problem worse

Although homeowners are encouraged to insulate their lofts, it unintentionally increases risk. The warmth stays in the living areas, but the loft itself becomes even colder.

“People think insulation protects everything,” Matt said. “But it actually traps heat below, so the tank is sitting in a freezing cold space. In the north of the UK, loft temperatures can plummet quickly.”

The heating mistake behind the biggest losses

Matt says there’s one error behind the most extreme claims, and this it turning the heating too low, or off completely, while the home is empty. Older storage heaters make things worse.

“Many can’t maintain a minimum temperature in very cold spells,” Matt warned. “That’s when pipes freeze.”

For holiday homes and holiday lets, the risk multiplies. Properties can be empty for days before anyone notices a leak, which is why insurance for holiday homes or holiday lets often includes specific winter conditions and checks that owners must follow.

Empty homes can also be the most vulnerable. “If no one is there to catch a leak early, the damage is massive”, Matt added. “We’ve seen significant structural damage in cases like this.” 

He also warned that some claims have been declined where owners didn’t keep heating at the minimum temperature required by their policy.

Key tips to prevent the problem 

• Test the ballcock valve – a sticking or faulty valve is one of the most common causes of major overflows.

• Look for signs of previous leaks – damp patches or wet insulation in the loft can indicate a problem that will worsen in freezing weather.

• Check lagging on pipes and the tank – thin or missing insulation is a major freeze risk in cold snaps.

• Keep loft temperatures safe – heating set too low (or switched off) leaves the loft at freezing point.

Get someone to look in if you’re away. A quick loft check can catch problems days before water shows downstairs. With temperatures dropping, Matt said this is the number-one winter risk for UK homeowners.

“A small heating tweak can save tens of thousands of pounds,” he added. “It’s the easiest decision you’ll make all winter.”