If you're planning on making large-scale improvements or extensions to your home it is vital that you inform your insurer, according to one expert.

It's a surprisingly common mistake home improvers can make. A MoneySupermarket.com report published this week found that, while many householders were planning to upgrade or improve their home over the coming months, a quarter (26 per cent) would not update their insurer about their plans.

A further 21 per cent said they didn't think it was necessary, while two per cent would avoid making the call in case it caused their premiums to escalate.

But as Homebuilding & Renovation magazine editor Jason Orme notes, letting your insurance supplier know of any radical changes to your property is vital to both protecting your investment and ensuring you don't fall foul of any loopholes in the event of damage to your property.

"It is really critical," he says. "Without telling the insurer that you have actually made these changes and added value to a house, then you risk losing all of the value that you added and your initial investment as well."

As the expert notes, it's a step many people are put off from taking simply because they are unaware they have to let insurance companies know.

If you've decked out a conservatory with LED lighting or have a lodger staying in a freshly painted loft conversion, the value of your property will have increased - and your old premium may not offer sufficient cover.

And Mr Orme noted that, although it differs on a case-by-case basis, the changes won't necessarily lead to any drastic changes in your premium. "Certainly in the cases of smaller alterations and ones that don't add space, then there is no guarantee necessarily that it will add anything to the premium whatsoever."

Undertaking an extension or a conservatory project is a great opportunity to introduce eco-friendly measures such as LED light bulbs to your home.