Typical domestic energy bills could hit more than £3,300 a year this winter, according to the latest forecasts.
Consultancy Cornwall Insight said the typical gas and electricity bill in England, Wales and Scotland could reach £3,363 in the new year.
The prediction comes as suppliers and consumer groups agreed a plan that could lead to a dedicated hotline and debt support for struggling households.
A set of government payments to help with bills starts to be paid next week.
However, there were calls for the government to do more to support families during the coming winter.
Cornwall Insight said that the typical domestic customer was likely to pay £3,244 a year from October, then £3,363 a year from January. The typical bill at present is about £2,000 a year.