Energy bills could soar by £1,645 within five months to hit £3,616, power experts at Cornwall Insight said.
UK households have already been struggling with the cost of soaring energy bills - but further increases are coming.
Energy bills for more than 80% of UK homes are limited by a price cap set by regulator Ofgem.
This price cap rose on April 1, 2022, from £1,277 to £1,971 per year on average.
But the price cap is being reviewed again in October. Cornwall Insight thinks this could rise by £1,388 to hit £3,359 in October.
It could then rise by another £257 to reach £3,616 in January 2023 - £1,645 more than it is now.
A statement from Cornwall Insight said: "Our predictions for the price cap have continued to rise amid wholesale market volatility.
"Due to uncertainty over Russian gas supplies ahead of winter, these latest forecasts indicate the potential longevity of high household energy costs."
This is worse than the analysis firm's earlier predictions, which put the October price cap at £2,879 and then £2,907 in January 2023.
But the highest predictions for energy prices have come from analysts at BFY, who said these could hit £3,420 in October - then £3,850 when the price cap is reviewed again in January 2023.
The most positive predictions for energy price rises in October are from regulator Ofgem.
Ofgem chief executive Jonathan Brearley has said the October price cap will be "in the region of £2,800" - although this comment was made back in May.
Cornwall Insight also thinks energy prices will stay "significantly above £3,000 a year until at least 2024".
Dr Craig Lowrey, principal consultant at Cornwall Insight, said: "Customers will be sadly used to these ever-increasing price cap forecasts.
"We have less than a month until the new price cap is announced and given the trends in the wholesale market and the concerns over Russian supply, unfortunately the only change to the prediction is likely to be up."
What is the Ofgem energy price cap?
Despite what its name suggests, the price cap isn't really a limit on how much you pay for energy - but it does work a bit like that.
Instead, it sets a limit on the rates a supplier can charge for each unit of gas and electricity you use and is reviewed twice a year.
The price cap is altered every six months, in April and October but Ofgem has proposed to change this to every three months instead.
This means it would be reviewed again in January.
Ofgem first introduced the price cap in 2019 and it is based on a number of factors including the wholesale cost of power in the previous six months.
