Almost 13 million households in the UK are owed a total of £1.7 billion by their energy suppliers, up 13.5% compared to last year.

That’s according to new research from Uswitch, which notes as winter ends, 46% of households are due a refund from their energy provider, with the average amount of £136, £10 more than last year, bringing the total owed up to £230 million – it highlights a tenth of billpayers are owed a rebate of more than £200.

Some energy providers do not automatically issue refunds to customers whose accounts are in credit and 57% of customers surveyed suggested their supplier has never automatically credited their account in the past.

Conversely, as the winter period comes to an end, 3.9 million households are in debt to their provider, owing a total of £548 million, an average of £142 each – this is up 16% on last year.

More than a quarter of households told Uswitch their debt is higher than it was last year and many stated they had taken measures to reduce their energy use over the winter period, such as turning down the thermostat (30%), only using the heating on certain days (24%) and turning down each radiator individually (23%).

Sarah Broomfield, Energy Expert at Uswitch, said: “Energy firms owe £1.7 billion to families across the UK. At a time when many people are finding their finances squeezed as well as using extra gas and electricity because they have to stay at home, this will be welcome news for anyone sitting on unclaimed credit from their energy supplier.

“More than a fifth of households say that the amount of credit or debt they’re in has increased in the last year and we hope that providers will act quickly to make sure that direct debit payments accurately reflect energy use.”