• For the first day of Christmas, homeowners could see greater energy efficiency
• A direct energy transfer of the energy saved through a heat pump over Christmas would be enough to cook 2,900 turkeys or 5 tonnes of brussels sprouts
• Instead of 11 pipers piping, families might want to look into their home’s pipework this winter

As families look ahead to warming their homes over the 12 days of Christmas, the innovation charity Nesta has calculated that every household could roast around 2,900 turkeys with the energy savings they’d achieve over the festive period if they swapped their gas boiler for a heat pump.

Heat pumps are low-carbon heating systems that use electricity to draw naturally occurring heat from the air, ground or water outside and transfer it inside to heat people’s homes. Heat pumps are highly efficient, typically producing three to four units of heat for every unit of electricity they consume. That’s also three to five times less energy consumed compared with a gas boiler.

Over the 12 days of Christmas (from December 25th to January 5th), Nesta has calculated using a heat pump instead of a gas boiler would save an average home 409 kWh through greater efficiency. This is equivalent to:

• Roasting 2,900 turkeys;
• Cooking over 5 tonnes of brussels sprouts;
• Warming 1,500 gallons of custard.

Nesta is encouraging anyone who is interested in cutting their energy usage over the festive period and beyond, while keeping their home warm, to check out getaheatpump.org.uk for more information about the efficiency of heat pumps. Homeowners could also arrange a visit to one in the New Year through visitaheatpump.com.

Daniel Lewis, principal researcher for sustainable future at Nesta, said: “For homeowners looking to be more energy efficient and reduce their Christmas carbon footprint, heat pumps should be their holiday hero.

“Heat pumps are around three times more efficient than gas boilers at heating people’s homes, so anyone using a heat pump to keep warm over the 12 days of Christmas could be saving ovenloads of electricity. Forget two French hens, the home heating energy savings compared to using a gas boiler would be enough to cook almost 3,000 turkeys!

“Anyone interested in getting a heat pump should check out getaheatpump.org.uk.”

A crucial factor holding back heat pump adoption is that electricity in the UK is expensive relative to gas, with the worst price ratio in Europe. Ofgem’s energy price cap puts electricity (at 24.5p/kWh) at 3.9 times the price of gas (at 6.24p/kWh). This means that despite the greater energy efficiency of heat pumps and all the energy that would be saved over the 12 days of Christmas, it will still cost £40 in electricity to run a heat pump and £36 in gas to run a gas boiler over that period.

Some heat pump owners can make savings by pairing their appliance with a special tariff that offers lower rates for heat pump use or rewards them for shifting their energy use away from peak times. For example, one tariff currently on the market offers heat pump users rates of around 15p per kWh, which would make the heating bill in the above example just £25 over the Christmas period.

However, the higher costs of electricity means that for homeowners on standard energy tariffs, Christmas with a heat pump or a gas boiler costs about the same. Nesta is calling for the Government to take steps to ensure the price of electricity comes down both in absolute terms and relative to the price of gas.

Daniel Lewis added: “Nesta’s Christmas wish is for cheaper electricity to make the energy savings of heat pumps add up to equivalent savings on energy bills for people using electricity to heat their homes.”

Notes to editors

1. The numbers of Christmas food items that could be cooked here with 409 kWh reflect how much energy is needed just to heat the Christmas food to the temperature needed to cook it. Nesta is citing this to convey how much more energy efficient heat pumps are than gas boilers. In reality, an oven is needed to actually cook the food - and in practice all cooking appliances lose energy in the process of cooking food. Nevertheless, an electric oven could be run for 102 hours (about 4 and a quarter days) with the energy saved from using a heat pump over the 12 days of Christmas. This would be enough to cook 47 turkeys.
2. Nesta’s calculations are based on Ofgem expecting a typical house to use 11.5MWh of gas annually and to use 75.3% of that in the winter period from October to March. For a gas boiler that is 85% efficient, that satisfies a heat demand of 7,359 kWh and over the 12 days of Christmas this equates to 485 kWh of heat demand to satisfy. A heat pump operating with a Coefficient of Performance of 3.0 would require 162 kWh of electricity to meet this heat demand, while a gas boiler would require 571 kWh of gas to meet this heat demand. This is a difference of 409 kWh of energy, equivalent to 1,472,000 kJ.
3. A typical house as identified by Ofgem is a 2-3 bedroom house, home to 2-3 people.
4. ‘Specific heat capacity’ is the amount of heat required to change the temperature of a mass unit of a substance by one degree.
5. The specific heat capacity of a turkey is 2.81 kJ/kg C and a small 3kg turkey that starts at 15 degrees C and needs to be 75 degrees C to be considered cooked would therefore need ~506kJ of energy to cook.
6. The specific heat capacity of brussel sprouts is 3.68 kJ/kg C. If the sprouts are 15 degrees C and are heated to 88 degrees C, 269kJ per kilo is needed. That’s 5,472 kg of sprouts, or just under five and a half tonnes.
7. The specific heat capacity of pasteurised whole cows milk is 3.77 kJ/kg C, which can be assumed to be a decent approximation for custard. To get custard to 70 degrees C, 207 kJ/kg is needed, so this would mean 7 tonnes of custard could be warmed. This is about 1,514 gallons (1 imperial gallon is ~4.55 litres).
8. An electric oven typically needs 2kWh of electricity for 30 minutes of use.
9. Nesta used the Ofgem energy price cap for 1 October to 31 December 2024 for cost calculations.
10. For more information on the analysis or to speak to one of the experts involved, please contact Kieran Lowe, Media Manager, on 020 7438 2576 or [email protected]. Spokespeople are available for broadcast interviews.

About Nesta

We are Nesta. The UK’s innovation agency for social good. We design, test and scale solutions to society’s biggest problems. Our three missions are to give every child a fair start, help people live healthy lives and create a sustainable future where the economy works for both people and the planet.

For over 20 years, we have worked to support, encourage and inspire innovation.

We work in three roles: as an innovation partner working with frontline organisations to design and test new solutions, as a venture builder supporting new and early-stage businesses and as a system shaper creating the conditions for innovation. Harnessing the rigour of science and the creativity of design, we work relentlessly to change millions of lives for the better.

Find out more at nesta.org.uk.