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The science of keeping warm by putting on a jumper

  • by JW

“Save a shepherd: put on a woolly jumper!”

Wearing multiple thin layers will keep you warmer than a single thicker layer, because warm air gets trapped between each piece of fabric. But there’s a knack to nailing it.


It might be considered rather callous of a politician to suggest we ‘wear a jumper to keep warm’ – as was indeed suggested a decade ago:

The UK prime minister’s office has been forced to row back from comments advising people who are cold but worried about fuel bills to wear a jumper. Number 10 said on Friday that wearing a jumper during the cold months was “something people may wish to consider”, prompting accusations of callousness the day after British Gas said it would raise energy prices by 9 per cent... Downing Street later rowed back from its statement, saying: “The prime minister would point people to a range of things being done to help people with their fuel bills, such as legislating to put everyone on the best tariff.” Downing St rows back from ‘wear a jumper’ comment | Financial Times

During the energy crisis of 1973, similar things were suggested – as we were reminded last year:

But there are cautionary tales for politicians, from the explosion of popular rage in France at fuel price increases that sparked the Yellow Jacket movement in 2018, to the PR disaster that followed former U.S. President Carter’s call for Americans to pull on their sweaters to cut energy use during the 1970s oil crisis. “The disagreement and resistance comes really from a deep, underlying sense of: ‘I don’t want other people to interfere with how I live my life,’” said Jan Rosenow, the director of European programs at the Regulatory Assistance Project, an NGO. It’s politically safer, he said, for politicians to challenge Russia by building wind farms and boosting solar panels — measures that many EU governments have backed. Why leaders won’t tell Europeans to put on a sweater to beat Putin – POLITICO

We don’t like to be told what to do – especially by politicians.

But what if your newspaper made the suggestion – as the Mail did last week?

When we reach for the thermostat dial, most of us will still hear the age-old money-saving advice of ‘Just put another layer on!’ echoing in our ears. But how much can the humble jumper actually save you? This Is Money has worked out how much you could save by putting on a jumper rather than reaching for the thermostat dial. Does wearing a jumper save money on energy bills… and how much? | This is Money

Young woman holding knitted woolen pullovers | 🇩🇪 Professi… | Flickr

Not everyone’s impressed though: To wish people would stop saying “just put a jumper on”? | Mumsnet

Unsurprisingly that includes the Guardian: Digested week: ‘put a jumper on’ is warm-housed people’s answer to energy costs | Joel Golby | The Guardian

Although the Mirror thinks it does indeed make good (economic) sense: Wearing a jumper could actually knock £320 off your winter heating bill – Mirror Online

Finally, though, beyond the politics, what about the science?

Wearing multiple thin layers will keep you warmer than a single thicker layer, because warm air gets trapped between each piece of fabric. But there’s a knack to nailing it... The Science Of Layering Your Clothes To Stay Warm This Winter | HuffPost UK Life

Save a shepherd: put on a woolly jumper! Why we must buy wool this winter and beyond | London Evening Standard | Evening Standard and Farm of the Week: Sheep farmer on a mission to bring back woollen blankets to solve heating bills crisis | Yorkshire Post