Energy suppliers have been urged to make bills clearer for their customers to understand.
According to consumers' association Which?, energy suppliers should make direct debit bills as transparent as possible to minimise confusion for energy consumers.
The organisation said energy suppliers should follow the lead of npower, which is revamping the format of its bills to incorporate a new "jargon buster" sector to explain unfamiliar terms.
The new format of bills will also include a clearer explanation of how the payable amount was calculated.
"Which? has complained for years that many consumers are left scratching their heads trying to work out how their energy bill was calculated," said Peter Vicary-Smith, chief executive of the association.
"We're delighted that npower has responded to our concerns by making its bills much clearer and we want other energy suppliers to follow suit."
The energy supplier's new bill will include a front page summary showing customer numbers, the amount owed by or to a customer and whether the bill is an estimate or a meter reading.
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