The price cap for the annual gas and electricity costs for private households in Great Britain will rise to £3,549 (the equivalent of more than €4,200) in October.
This was announced by the energy regulator Ofgem on Friday.
The price cap currently stands at £1971, having already made a significant jump from £1277 at the time since last autumn.
The costs are based on the consumption of an average UK household of two to three people using 2,900 kilowatt hours of electricity and 12,000 kilowatt hours of gas per year.
If you consume more, the price cap does not protect you from an even higher bill.
With the increase in the price cap, the pressure on the government to announce measures to relieve households increases.
However, a concrete plan is not expected before September 6th, when the successor to outgoing Prime Minister Boris Johnson will be decided.
Secretary of State Liz Truss, who is considered the favourite, only announced "immediate help".
Ofgem boss Jonathan Brearley described the increase as "devastating news" for families already living on the poverty line.
Addressing the new government, which is due to start work in early September, he said: "We are working closely with you.
But we must all act with urgency and determination to resolve this issue," he said.
Interim Finance Minister Nadhim Zahawi admitted the announcement caused "stress and anxiety" among people.
But help is on the way, he assured.
So there should be a one-time aid of 400 pounds for all households.
Welfare recipients will receive an additional £650 and pensioners an additional £300.
The cap is expected to be raised sharply again in January and April to reflect the high market prices for electricity and gas and to protect providers from collapsing.
It is projected that this could increase the annual energy bill for the average household to as much as £7,000.