Energy debts have fallen by £126 million since last year but more than 2 million households still owe £267 million to suppliers before winter, research has suggested.
The figures were extrapolated from an online survey of around 2,000 people conducted on behalf of price comparison website Uswitch.
The responses indicate the number of households in arrears has fallen by 610,000 – or 21 per cent to 2.3 million. They on average owe £115.
The research also found that more than a third (36 per cent) have concerns about paying their energy bills this winter.
According to the survey, four in ten will wear extra layers to keep costs down and three in ten will turn the thermostat down. Almost one in five (17 per cent) will not put their heating on, even in cold weather – the equivalent of 4.6 million households.
More than half of those in debt (56 per cent) said they had not been contacted by their supplier about the debt or offered advice about repaying the outstanding amount.
Richard Neudegg, head of regulation at Uswitch.com, said: “Thankfully, the number of people in energy debt this year has fallen as more and more people take control of their energy bills and shop around for savings.
“But sadly, the good news doesn’t extend to everyone. Over 1.5 million households still say they will have to choose between heating and eating in order to pay their energy bills this winter. That’s a terrifying prospect for anyone to have to face.
“Energy companies need to do more to make customers aware if they’re falling behind, and what their options for paying off the debt are, before people have to start making drastic decisions which could affect their health and wellbeing.
“Likewise, more needs to be done to reform government support so that it’s targeted at the most vulnerable households, where it will have the most benefit.
“Anyone worried about debt should speak with their energy supplier to set up a repayment plan, get energy saving advice, and check if they are eligible for free insulation or grants to help keep costs down.”