HOUNSLOW npower customers could claim up to £100 as a refund to gas bill overpayments three years ago.

Consumer Focus, an independent organisation for consumers across the UK, are putting out the appeal to npower customers in the borough who may not realise they are owed money.

Spokesman John Cottrill said: "It will be affecting people in Hounslow. It would be great to remind people to get the cash if they are entitled to it".

Consumer Focus announced in October last year that npower were offering £70m of refunds to customers across the country.

But so far in greater London, less than half of the company's customers have claimed their money back.

The refunds have been offered by npower after it emerged that customers were likely to have paid for more higher priced gas units than they expected to in 2007 after the company changed how it charged for these units but "did not communicate the changes effectively".

A spokesman for Consumer Focus said: "npower has worked closely with Consumer Focus to ensure a fair amount is paid back to the customers affected.

" npower have written to all existing customers and to the last known address for all former customers. They have offered payment through a bar-coded letter that can be cashed at any Post Office.

"Consumer Focus is urging anyone who has been contacted by npower to make sure they cash in their payment at the Post Office as soon as possible, as the payment letters are only valid for six months from the date of issue".

Volker Beckers, npower CEO, said: "We are working closely with Consumer Focus to maximise the number of eligible customers and former customers who claim their payment. We are still seeing redemptions running at more than £1 million per week and we hope that those who have unredeemed letters will redeem them soon".

Npower is offering repayments to 1.89 million households in total.

The watchdog is urging people who were customers of npower in 2007, but have since left the supplier or moved house, to call npower’s helpline on 0800 975 7938 or visit npower’s (www.npower.com) to find out if they are entitled to a refund.