Some 12,000 lives a year have been saved since the introduction of the winter fuel payment, according to a leading OAP charity.
Age UK published research in the Journal of Public Health which it said showed the number of excess winter deaths - defined as deaths which would not have happened anyway - among people over 65 had fallen by 50% as a result of the energy benefit.
It comes after official figures showed the death rate in England and Wales was around a third higher than normal for this time of year, with 28,800 deaths registered in the fortnight ending January 23.
Millions of people born before July 1952 are entitled to between £100 and £300 tax-free to help pay heating bills during winter and the charity said it had made a "significant impact" since it was introduced in 1997.
"It really does help"
Professor James Goodwin, head of research at Age UK, said: "This new research provides us with the strongest indicator yet that the winter fuel payment really does help to reduce excess winter deaths among older people.
"We have always known that the winter fuel payment provides a vital cash boost to help people meet these increased heating costs - we now have evidence that suggests it can literally make the difference between life and death."
The majority of excess winter deaths are among older people the research also revealed that over the last 60 years 2.6 million people - the majority aged over 65 - have died unnecessarily because of the cold.
The charity estimates that the cost of cold homes to the NHS is around £1.36bn every year.
Earlier this month, the Office for National Statistics revealed the death rate in the middle two weeks in January had been 32% higher than the average for that period over the previous five years (21,859).
The ONS suggested that the flu virus and the cold snap could be to blame for the increased death rate.
10 simple ways to keep your house warm this winter
Winter fuel cash 'saving OAP lives'
Of course you should make sure the doors and windows are shut properly, but you should also check each one for draughts too. A good old fashioned draught-excluder will stop the wind whipping under the doors, and draught-proofing strips around doors and windows should see off the worst of the chills.
It's not the kind of DIY job that anyone loves, but a quarter of the heat in your home is lost through the roof, so it makes a big difference. Once you've insulated the loft, the roof space will be colder, so make sure you have insulated any water pipes and tanks, and draught-proofed the loft hatch.
If you have thicker curtains, ideally with a thermal lining, you're likely to lose 25% less heat through the window. It's also worth considering curtains over external doors, to prevent heat from escaping. However, make sure you draw them back during the day to make use of any glimmers of sunshine we get.
If you don't have a working chimney but you do have an open fire, then you'll be losing heat through the chimney. If you place a chimney balloon in the chimney and inflate it, it will trap the warm air in.
If you stick the sofa in front of the radiator you'll waste a fortune keeping the back of the sofa warm.
Many people will remember elderly relatives applying tinfoil in a hap-hazard manner years ago, but it doesn't have to be noticeable, and will reflect half the heat back into the room.
Bare, varnished floorboards have been popular for a while, but unless they are carefully filled and draught-proofed, you can lose 10% of your heat through the floor. If filling the floorboards is impractical, a carpet may be a simple solution.
There's no point in heating any rooms you don't use, so turn off radiators in unused rooms, and heat the rooms you tend to occupy instead. Once the spare room gets chilly, you'll need to keep the door closed, and use a draught-excluder to stop the chill spreading.
If your kitchen is the heart of the home you don't need the house so warm during dinner time, because you can use the warmth of the oven to keep you all toasty. Get some baked potatoes in the oven, some soup on the hob, and no-one will notice the rest of the house has grown a little cooler.
It may seem a bit Victorian, but having a woodburner in the fireplace allows you to burn a cheap fuel, and enjoy the heat without the smoke. Burning wood costs less than gas and two thirds less than electricity, so you can stay toasty for less.