Does wearing a jumper save money on energy bills… and how much?

As the UK goes through another cold spell, households are desperate for ways to cut their record heating costs.

When we reach for the thermostat dial, most of us will still hear the age-old money-saving advice of “Just put on another coat!” echoes in our ears.

But how much can the humble jumper actually save you?

This Is Money has found out how much you can save by putting on a sweater instead of reaching for the thermostat dial.

Based on our experiment, the average household could save £250 a year, rising to £300 when the government’s energy price guarantee is revised in April.

To work this out, we have set some parameters. First, we assume that someone feels warm at a room temperature of around 18C, and starts to feel cold slightly below that.

Of course, we all start to feel hot or cold at different temperatures and live in buildings with different degrees of insulation.

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But 18C is the recommended room temperature in winter by the World Health Organisation, while the Energy Saving Trust suggests rooms should ideally be 18C to 21C.

In cold weather, it has been government advice to heat rooms to at least 18°C ​​for health reasons, especially in the interests of elderly residents.

This is because cold weather can increase the risk of heart attacks, strokes, and respiratory infections.

Putting on a jumper before turning up your central heating temperature could save you £250 a year on energy costs

However, most Brits seem to prefer it to be slightly on the warmer side of the 18C to 21C range. A survey by Uswitch previously found that an estimated 17 million homes in the UK have their thermostats set above 20C – that’s about 70 per cent of all households.

To determine how much you save by wearing a sweater, we also assume that everyone in the property is willing and able to wear more layers and accept that the general room temperature is slightly lower.

How much money wearing a sweater really saves you

If you sit in a room with a temperature of 15°C and wear a t-shirt, the average person will probably get cold after a short time.

But if you add a light wool sweater to it, it traps extra warm air near your skin, making you feel warmer.

To find out how much heat is generated, we used a thermometer and found that a light sweater increased your temperature by 2C.

This means the room now feels like 17C, close to the target temperature of 18C.

However, wearing the same T-shirt with a thicker wool sweater on top added 4C to the wearer’s temperature and made them feel very warm indeed.

Wearing one of the above sweaters should mean that the wearer can afford to turn down their central heating slightly to compensate for feeling warmer.

Turning your thermostat down just 1C can save you around 10 percent on your annual energy bill, according to the charity Energy Saving Trust.

The energy bill for the average household with an average energy consumption is capped at £2,500 a year because of the government’s energy price guarantee, unveiled last year to help cover rising costs.

That will last until the end of March this year when it rises to £3,000 until April 2024.

Ten per cent of £2,500 equates to a saving of £250 a year for just a 1C drop in your thermostat’s temperature, rising to £300 a year from April 2023.

Lowering your thermostat by 2C won’t mean saving £500 a year, though, because the rule only works once – and after that the savings are smaller and harder to work out.

As mentioned earlier, there are also huge variables that affect how many layers you can save on energy bills.