UK households owe £1.3bn to their energy suppliers, two months before bills are set to soar by more than 80%.
The overall debt bill is already three times higher than it was a year ago, according to analysts at comparison site Uswitch, and it seems likely it will grow further over the winter.
Six million homes across the UK owe an average of £206 to their energy provider, according to a survey from the company. In April the same average debt was £188.
Normally at this time of year people have built up a small war chest to help even out the increased bills during the winter months.
Uswitch advises people falling into debt to speak to their provider to work out a more affordable payment plan.
Regulator Ofgem is expected to raise the price cap on energy bills to £3,582 per year for the average household the UK from the beginning of October, according to a new forecast.
Analysts at Cornwall Insight have predicted further rises, to £4,266 in January and then £4,427 from the start of April.
"Energy debt has hit an all-time high with the worst possible timing, turning this winter's energy price hike into a deeply precarious situation for many households," said Justina Miltienyte, head of policy at Uswitch.
"This is an alarming situation, as summer is traditionally a time when households are using less power for heating, which helps bill payers to build up energy credit ahead of the winter."
Uswitch's survey showed eight million households have no credit balances, meaning they have no cushion against the winter misery.
Nearly one in five people (18%) said they are worried about their supplier forcing them to take a prepayment meter if they fall behind on bills, although 38% said they did not know their supplier could do this.
Citizens Advice said it has helped more than 47,000 people with energy debts so far this year. The average debt amount was more than £650, the charity said.
Ministers are set to hold talks with energy giants on Thursday to discuss measures to ease the cost of living.
Chancellor Nadhim Zahawi and business secretary Kwasi Kwarteng will meet bosses to discuss rising prices and the sector's profits.
It comes as prime minister Boris Johnson faces growing criticism for not announcing further support beyond the £15bn package set out in May.
On Tuesday, Money Saving Expert's Martin Lewis called on Liz Truss and Rishi Sunak to set aside their differences to tackle the problem together, warning the country was facing a "national cataclysm".
He said the "zombie government needs to wake up sooner than 5 September", when the new Tory leader and prime minister will be announced, as the new bill predictions are "unaffordable for millions".
The leadership debate must not ignore this portentous national cataclysm any more.
-They can't say they weren't warned
-The excuse "we need to wait for Ofgem figure" doesn't wash. In May govt asked Ofgem for forward guidance & made plans based on that. It can do the same now..
— Martin Lewis (@MartinSLewis) August 9, 2022
On BBC's The Today Programme this Wednesday morning, he explained that for every £100 a month that people pay on direct debit for their energy bills now, that will go up to £181 probably at the end of August, before the new prime minister in place, and rise again to £215 in January.
"Sitting down with the energy companies is the right thing to do but ultimately it is government and government alone that can make the decision to stop the terrible cataclysmic risk millions of people in our nation face this winter and it needs to do it soon," he said.
Tony Danker, head of the CBI, also called for both to get in a room together to sort the issue out.
Derek Lickorish, chairman of the energy supplier Utilita Energy and former chair of the government’s committee on fuel poverty, is calling for a “social tariff” funded by the Treasury to help the poorest in society.
About 10.5 million households will be in fuel poverty for the first three months of next year, according to estimates from the End Fuel Poverty Coalition (EFPC) published on Tuesday – meaning that their income after paying for energy will fall below the poverty line.
That means that nearly one third of households in the United Kingdom will face poverty this winter after paying energy bills.
Greg Jackson, the founder of of Octopus Energy, said the government needs to improve its offer of a £400 discount to households.
“If the £16bn package was right previously then clearly it’s not sufficient now and we need to look at a similarly significant assistance from the government for this winter,” he told BBC's Today programme.
There are several ways for customers to save on bills. One of the simplest is to turn down the flow temperature on your condensing combi boiler.
Doing this will allow the boiler to run more efficiently and could save around £200 off an average energy bill.
Another easy saving is to turn off the pre-heat mode on the boiler, which could mean hot water taps taking longer to heat up, but could save hundreds of pounds a year.
Experts also advise households to check if they are eligible for extra support.
Watch: Why are gas prices rising