Older people have seen their energy bills more than double since 2005, research from over-50s specialist Saga has found.
The average annual spend on energy bills for the over-65s soared to £1,356 last year, more than twice as much as the 2005's average of £669.
Across the UK, 12.9 million pensioners spent an estimated £17.4 billion on energy bills in 2012. However, the figures don't take into account the effects of a recent string of price hikes announced by energy companies, pushing costs up further this winter.
Saga argues older people are disproportionately affected by increases to living costs, as they are often trying to live off a fixed income or savings.
Ros Altmann, director-general of Saga, says its research found 29% of older people are raiding their savings every month to make ends meet.
She says: "We are still to feel the full effects of the latest price rises so energy costs are likely to put even more of a financial strain on households in 2013.
"While incomes have increased in the last seven years, they have not kept pace with the rate energy and fuel costs have risen, meaning people are spending more of their income on fuel."
The findings come in the same week as Prudential said people planning to retire this year expect to be living off the lowest average incomes recorded in six years (see the Retirees face 'lowest incomes in six years' MSE News story).
Financial information website Moneyfacts also reported this week that annuity rates, which set the size of someone's retirement income, plunged at their steepest rate in 14 years for men in 2012.