While cheap energy remains scarce, many direct debit customers in the UK are in significant credit on their energy bills, according to a consumer organisation.
A Which? study revealed that 13 per cent of direct debit customers are in credit of £100 or more on their account, with the average figures being £84 for gas bills and £74 for electricity.
The build-up of credit on energy accounts is the subject on which customers were most vocal in the survey, with many homeowners unhappy that credit has been allowed to build up in such difficult economic times.
Martyn Hocking, editor of Which? Money, said: "It seems incredible that energy companies can take hundreds of pounds more than they need to from their customers and profit from the interest that this money will earn at our expense."
Energy companies have said they take measures to ensure accounts are kept as close to zero as possible, although the Energy Retail Association said figures will sometimes fluctuate.
Paying for energy bills by direct debit is one of the cheapest ways to settle gas and electricity accounts.
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