Energy suppliers have been named and shamed by consumers for inaccurate billing, according to uSwitch.

A survey carried out by the financial comparison site showed one in three households have had to deal with at least one inaccurate energy bill over the last two years. Such mistakes took an average of two months to sort out, although 13% were dealt with successfully in a day.

Due to the estimated billing system the energy industry uses, payments currently match usage on 26% of energy bills, with 40% of customers owed money and 26% in debt to their supplier. More than 11 million energy customers (43%) have unexpectedly owed money to their supplier at some point, after a discrepancy between estimated and actual readings. The average amount owed was £137.

Ann Robinson, director of consumer policy at uSwitch.com, said: “I suspect that suppliers will continue to be haunted by this reputation for inaccurate bills until smart meters finally lay that ghost to rest – unfortunately that won’t be for many years. In the meantime suppliers are trying to work with their customers to resolve the issues and tackle the root cause – discrepancies between estimated and actual readings – which can often leave households unexpectedly out of pocket.

“Suppliers are making it easier than ever for customers to read and supply their own meter readings and in some cases are even rewarding those who do so. But whether there is a reward or not, I would still urge consumers to respond to meter reading requests or to supply their own readings.”