Energy regulator Ofgem has ordered utility firms to repay hundreds of customers who have been overcharged up to three times too much for their gas.
The problem came to light when E.on, one of the Big Six energy firms, revealed that 350 households and small businesses had been affected by the problem which was the result of a mix up with older imperial and more modern metric meters. One customer has been overpaying for 15 years, E.On admitted.
Ofgem has given other suppliers until Friday to identify how many of their customers are also affected.
Craig Salter, energy spokesman for Citizens Advice Scotland, said: “Energy customers should never have to pay for the mistakes of suppliers, and it is right that these customers will now be refunded.
“Accurate billing is essential to ensure customers don’t pay over the odds for their energy.
“The move from Ofgem to order suppliers to refund customers is welcome, but energy companies must take action to ensure that mistakes like this are not repeated in the future.”
A number of customers have also underpaid over the same period. They will not be expected to pay back the money.
Ofgem said the issue has been caused by suppliers mixing up the unit - metric or imperial - that the meter is measuring gas consumption in, and the unit recorded in their back office systems.
E.On said: “In the rare cases where an issue has been identified amongst the company’s current customers it was generally because customers with a metric meter had been registered as having an imperial meter or vice versa, resulting in customers either being overcharged or undercharged.”
Ofgem said that after a “reaonsable period of time”, firms should calculate the amount of credit they have been unable to return to affected customers and contribute “an equivalent amount” to a charity.
A spokesman saide: “Ofgem is aware that a very small number of gas customers are being incorrectly charged for their energy use and has taken fast action. Working with Energy UK, we’re ensuring suppliers take immediate and decisive action to identify affected customers.
“E.on has done the right thing in coming forward.”
Ofgem said that affected customers will be contacted by their supplier.