The average UK gas boiler emits more CO2-equivalent emissions in a year than taking seven transatlantic flights, according to analysis from the charity Nesta. However, new polling shows that 88% of UK adults significantly underestimate the carbon emissions from our boilers.

Home heating accounts for 38% of all UK gas use, and an average household gas boiler emits greenhouse gases equivalent to approximately 2.2 tonnes of CO2 per year. This is roughly equivalent to:

• Taking seven flights between London and New York
• Driving from Land’s End to John O’Groats (1,347km) 13 times in a new petrol or diesel car
• Streaming TV content 24/7 for four years, enough time to watch every episode of Coronation Street back-to-back eight times (10,543 episodes)
• Eating 1,263 quarter-pounders made with British beef
• An average household binning all recyclable packaging for 14 years
• Leaving a 10W lightbulb on for 139 years

A representative poll of 2,000 UK adults, conducted by Opinium for Nesta, asked respondents to estimate the carbon emissions associated with a range of activities. 50% of respondents accurately estimated that taking 6 transatlantic return flights would emit ‘very high’ annual emissions (more than 1.5 tonnes of CO2), whereas only 12% correctly put heating their home with a gas boiler in this category.

Overall, people estimated the carbon emissions from a gas boiler to be broadly the same as driving 30km per day in a new petrol or diesel car or eating 40kg of British beef. These represent the average annual car use and meat consumption in the UK respectively. In reality, an average boiler generates 3 times more carbon than the beef and 1.7 times more than the car. Key gaps between people’s perceptions and reality included:

• 88% of respondents underestimated annual gas boiler emissions
• 83% overestimated emissions from binning a year’s worth of recyclable waste
• 55% overestimated emissions from leaving ten 10-watt light bulbs on all year

When respondents were shown the true emissions associated with each activity, two thirds of people said that it wouldn’t change how much they would prioritise taking action to reduce their emissions in that area. This was consistent across all activities, despite boiler emissions being significantly higher than people’s expectations and many other activities being lower.

“For most people, your boiler is probably the most environmentally damaging thing that you own.” explains Andrew Sissons, Deputy Director of Nesta’s Sustainable Future team. “People significantly underestimate the emissions caused by their boilers, which holds us back in tackling one of the most important sources of carbon emissions. But knowing how much carbon a boiler emits is only half of the battle. Most people in the UK still aren’t in a position to consider installing an alternative to a boiler, such as a heat pump, often for financial reasons.

“Heat pumps are a much more efficient and environmentally friendly alternative to boilers. While they are expensive at present, we expect their price to fall over time, particularly if the government follows through on its plans to make electricity cheaper by shifting environmental levies.

“We want to encourage more people to think about their next heating system when their boiler comes to the end of its lifetime. In the meantime, there are steps that people can take to reduce their boiler emissions and gas bills in the short term, such as improving home insulation and reducing the flow temperature of their boiler.”

Nesta has developed a carbon calculator where people can quantify the environmental impact of their own boiler. They can input their own gas readings, or get estimates based on their home type, and see how their emissions compare to other activities.

Respondents were told that the average person in the UK generates approximately 8,340kg of CO2 per year. They were then asked to rank several activities by their emissions, in the following categories:

• Low impact (0-250kg of CO2, 0-3% of average annual emissions)
• Medium impact (250-500kg of CO2, 3-6% of average annual emissions)
• High impact (500-1,500kg of CO2, 6-18% of average annual emissions)
• Very high impact (1,500+ kg of CO2, more than 18% of average annual emissions)

The full report and data tables from the Opinium polling are available for download.

Excluding ‘don’t know’, the respondents gave the following estimates for each activity: