The charity’s warning comes after Prime Minister Liz Truss said she was “completely committed” to the triple lock on state pensions after questions were raised over whether the UK Government would scrap the policy.
However, Age Scotland head of policy Adam Stachura said the organisation was still concerned rising bills could lead to increasing mortality rates this winter after hearing from pensioners “stripped to the bone”.
Although Age Scotland welcomed the move from the UK Government to commit to the triple lock, Mr Stachura said it was a “wholly unnecessary” period of anxiety for pensioners.
“Until this is signed, sealed and delivered we cannot be sure that it is safe.” Mr Stachura said.
Last month, National Records of Scotland published figures which showed life expectancy in Scotland had dropped for a second year running, with poverty labelled a ‘key factor’.
Mr Stachura said: "We are hearing of people skipping meals, living in one room of their own, not using their energy in the summer.
"In darker and colder months, people will have to use more energy to keep their home semi-manageable and it will cost 25 per cent more.
"In the summer, we identified 42 per cent of over-50s self-identified as being in fuel poverty and that’s higher than it’s ever been before.”
Asked if he was concerned mortality rates would rise amongst pensioners this winter in comparison to previous years, Mr Stachura said: “Absolutely.”
The charity calculated half of older people in Scotland live in the least energy efficient homes, leading to further costs to ensure a home is heated properly.
"We are very concerned that, on top of unmanageable debt, people won’t use heating or sparingly use their heating,” Mr Stachura said. “They are already stripped to the bone.”
Under pressure from backbench MPs, Ms Truss agreed to an inflation-proofed increase in pensions on Wednesday.
Triple lock means the state pension must rise each year in line with the highest of three possible figures – inflation, average earnings or 2.5 per cent.
Despite saying the commitment to triple lock offered a “glimmer of hope” for more stability in the future, Mr Stachura said it “would not make pensioners rich by getting to £10,00 a year”.
There are around 450,000 out of about one million pensioners in Scotland whose income is too low to qualify for paying for income tax, according to the charity.
Mr Stachura said: “That essentially means their annual income is around £12,500 and that’s been fixed while we’ve been meeting these surging costs. Essential items of food are up 30 per cent, energy bills are already twice as high as they were.”
Around 150,000 pensioners in Scotland rely solely on their state pension, affecting mainly women who are often on lower pensions, Age Scotland said.
The Liberal Democrats, which introduced the triple lock under the Conservative/Lib Dem coalition, are calling for an “immediate guarantee” both pensions and social security will rise in line with inflation.
Responding to Ms Truss’s commitment, Wendy Chamberlain, the Liberal Democrats work and pensions spokesperson, said: “This will bring cold comfort to pensioners across the country after a precarious wait.
“Once again, this Government has had to be dragged kicking and screaming by their own backbench’s backlash into doing the right thing, leaving yet more uncertainty for our most vulnerable.”
Ms Truss had faced a fresh wave of anger after No 10 said the policy was under review and her new Chancellor failed to commit to it as he seeks to plug a multibillion-pound black hole.
But she told Prime Minister’s Questions: “We’ve been clear in our manifesto that we will maintain the triple lock and I’m completely committed to it – so is the Chancellor.”
On Twitter later, Ms Truss said “protecting the triple lock” would “ensure pensioners get the most generous support”.
Downing Street said the decision was taken “jointly” by Ms Truss and Mr Hunt on Wednesday morning ahead of her appearance at the despatch box.
The Prime Minister’s official spokesman said it reflects the “unique position” of pensioners who are unable to increase their income through work.
“She and the Chancellor have discussed and agreed the position the Prime Minister set out this morning,” the spokesman said.
However, Ms Truss continues to face a rebellion on another front after she refused to give the same commitment to increasing benefits in line with inflation.
Tory John Baron urged her to show “compassion in politics” by maintaining the inflation link.
Ms Truss said: “We will always work to protect the most vulnerable”, but stopped short of using the same firm language she reserved for pensions.
Existing policy dictates that, from April next year, the state pension and benefits should increase by 10.1 per cent, the figure for Consumer Price Index inflation in September.
Tory critics have been threatening to rebel if Ms Truss backtracks on the commitment on welfare payments, which would hit claimants with real-terms cuts.
The Prime Minister declined to give a commitment to also increase benefits in line with inflation, while her spokesman said no decisions have been taken.
Ms Truss has faced pleas from the Tory benches to explain her policies on benefits and social care amid ongoing uncertainty.
Conservative MP Steve Double (St Austell and Newquay) told a Commons debate: “We really do need to know what the Prime Minister’s policies are.”
He said: “I think the one thing we should all be able to depend on is no matter how difficult times are, that the Government won’t make those decisions even harder and sadly that is what has happened as a result of the rushed mini-budget. The fallout from that has been a loss of confidence.”
Mr Double welcomed the commitment to the triple-lock on pensions, adding “we must do a similar thing for benefits now, it’s absolutely vital, I believe”.