British Gas has announced increases to the gas and electricity prices it charges customers.
It has raised its charges for both types of fuel by about 6%, adding £80 a year to the average dual fuel bill.
Britain's biggest energy supplier said the "unwelcome" increase would come into effect on 16 November.
Its rival SSE, which trades as Scottish Hydro, Swalec and Southern Electric, has already said it will raise its prices by an average of 9% from Monday.
"We know that household budgets are under pressure and this £1.50 per week rise will be unwelcome," said managing director Phil Bentley.
"However, we simply cannot ignore the rising costs that are largely outside our control, but which make up most of the bill."
British Gas also warned that the rising cost of government energy policies was likely to add even more to household bills next year.
Rising costsSpeaking to the BBC, Richard Lloyd of consumer group Which? criticised the opacity and lack of competition in the energy market.
"What we need to see is action from the government and more pressure on... these very big lazy companies who think it's OK to clobber people with above-inflation price rises at the very time when they can least afford it," he said.
"Everybody knows that this is a market that is not competitive, not properly working for consumers.There is very little pressure on British gas to be efficient and to keep these price rises to a minimum."
Over six million households in England already plan to cut back on their heating this winter because they are worried about affording their bills, according to Audrey Gallagher of the government-sponsored watchdog Consumer Focus.
"Today's price rise will leave customers even more worried about the cost of heating their homes," she said.
British Gas last raised its tariffs in August 2011, when gas prices went up by 18% and electricity prices by 16%.