• Real-world trial demonstrates that homeowners are comfortable with remote automation of heat pumps to reduce electricity use during peak times, allowing them to maximise savings while staying warm

Remote control operation of heat pumps to avoid expensive electricity peak demand periods can save households money and reduce carbon emissions while keeping their home warm, new research finds today.

The innovation foundation Nesta partnered with research institute Centre for Net Zero (CNZ) to conduct a randomised control trial to find out how much remotely operated automation of heat pumps can reduce household electricity consumption by shifting usage during times of peak demand.

Half of the 43 volunteer homeowners recruited for the trial then had their heat pumps remotely controlled for four hour periods. For the first two hours, the heat pumps were used to ‘preheat’ homes, raising the internal temperature. For the second two hours, the heat pumps were turned down - aiming to reduce household electricity consumption from the grid at a time of peak demand.

The trial found that remotely controlling participants’ heat pumps to flex consumption around peak demand led to:

• An average 74% reduction of typical heat pump electricity consumption (0.382 kWh per half-hour across a two-hour window).
• An average 32% reduction of typical household electricity consumption (0.123 kWh per half-hour across a two-hour window). This figure is lower partly because many participants have solar panels and batteries; for households without these, overall demand reduction will likely be closer to the above figure.

The real-world trial’s findings show that remotely controlled automation of heat pumps could help people make savings. Through electricity tariffs that offer energy cost reductions for usage during off-peak times - known as “time-of-use tariffs” - users can save without having to manually manage their electricity usage themselves.

The average internal temperature in the homes of those who took part in the four-hour ‘events’ increased by 0.85oC during the two hours when the homes were preheated before the heat pumps were turned down for two hours. The internal temperature was still on average 0.16oC higher at the end of that second two-hour period, compared to the start of the preheating period. This suggests that preheating helped maintain the internal temperatures of homes.

The majority of participants were happy with the internal temperature of their home, with 8 in 10 of participants (81%) surveyed afterwards saying that they were either “Satisfied” or “Very satisfied” with the temperature in their home.

Participants also had the option to opt out of having their heat pumps remotely operated before the four-hour ‘events’ and the trial also found that participants were broadly happy having their heat pump remotely automated - only 9% opted out, which was typically because they were not going to be at home.

Shifting the times people use their heat pumps - or “flexing” them - will also bring direct savings to households through their energy bills. Recent empirical analysis by CNZ based on over 6500 households found that even without third-party automation, a simple time-of-use tariff for heat pumps currently on the market is reducing annual energy bills by 18% (or £318) compared to a standard tariff.

A separate report released today from Cornwall Insight and commissioned by Nesta finds that the same kind of flexing - preheating before a time of peak demand, and then reducing consumption during the peak - has the potential for even bigger savings for heat pump users. The modelling finds households can make savings of up to £650 a year on the average annual electricity bill, when switching from a fixed heat pump tariff to a time-of-use tariff and flexing heat demand. These savings are largely achieved by shifting demand into periods when wholesale costs are lower.

Decarbonising domestic heating is critical if the UK is to reach net zero by 2050. The Government's plan to decarbonise heat is based on installing 600,000 heat pumps per year by 2028, rising to as many as 1.9 million per year from 2035. But replacing gas boilers with heat pumps powered by electricity will require a greater supply of electricity. Electricity demand is expected to more than double by 2050, and this rise will increasingly be met by variable renewable generation.

Lowering the demand for electricity at peak times can help reduce the pressures on the electricity grid, such as on high-demand cold days, bringing system costs down for everyone and reducing the cost of upgrading and reinforcing the grid to meet demand.

Lowering electricity consumption also reduces the electricity bills of consumers and can lower carbon emissions, because fossil fuel generation is often currently used alongside renewable generation to meet peak demand.

Andy Regan, senior mission manager for sustainable future at Nesta, said: “Heat pumps are the most efficient low-carbon alternative to fossil fuel boilers for keeping people’s homes warm. Our experiment shows heat pumps could play a positive role in managing the energy system as more people use electricity for green heating, while also cutting people’s electricity bills.

“Time-of-use tariffs already exist to encourage people to switch around their electricity usage, allowing savvy consumers to make real savings. But we have found that remote control automation of heat pumps can help even more people shift their consumption while staying warm. Participants were comfortable with these tweaks being made and this shows how heat pump technology can reduce the burden on consumers to make these kinds of savings.

“Crucially, remote control automation could be scaled up to reduce the cost of upgrading the electricity grid to meet higher electricity demand as people switch away from fossil fuel heating.”

Andy Hackett, Senior Policy Adviser at Centre for Net Zero, said:

“Heat pumps will be a central technology in decarbonising Britain’s homes, which are responsible for about a fifth of its emissions. We need to develop ways to optimise this future electricity demand in a way that works for the grid and consumers.

“CNZ’s prior research has shown that time-of-use pricing for heat pumps is very effective at shifting demand. This latest trial shows how we could scale heat flexibility with a broadly acceptable form of automation - remote-controlling smart thermostats while maintaining comfort. Without any ongoing effort, households with heat pumps can seamlessly shift demand to support the grid and cut their own bills.”

Notes to editors

1. Nesta contacted Octopus Energy customers in three geographical areas in which Octopus Energy Services could install the necessary equipment to participate in our trial. Participants were offered a £100 gift card as an incentive to participate, alongside a free smart thermostat and a heat pump monitor to any households that needed them. Nesta used a two-armed randomised controlled trial to estimate the impact of our intervention on household consumption. Nesta used stratified randomisation (stratifying on estimated annual consumption quintiles) to allocate customers to Treatment or Control groups. The Treatment group took part in the HeatFlex events, with their heat pumps remotely controlled; the Control group only had their household and heat pump consumption measured without taking part in events.
2. Nesta ran 30 events from February 2024 to April 2024, typically comprising a two-hour preheating period and a two-hour flexibility window. HeatFlex events typically occurred between 16:00 and 20:00 on weekday evenings, with the first two hours for preheating, and the second two hours for the flexibility window. Participants were notified by email 24 hours before an event took place, and were able to opt out of an event if they were not going to be at home, or for any other reason.
3. In a separate report, Cornwall Insight, commissioned by Nesta, modelled electricity wholesale, network, and policy costs associated with operating a heat pump flexibly in response to price signals through a range of tariff structures over a ten year period from 2024. In the modelling, when electricity prices are higher, the heat pump responds by pre-heating the home at cheaper rates earlier in the day and maintaining a comfortable temperature, but avoiding running when electricity costs are higher. Alternatively, high costs are avoided through the use of self-generated and self-stored energy using installed solar PV and battery storage. The modelling assumes the heat pump consistently avoided expensive peak periods.
4. For more information on the analysis or to speak to one of the case studies or 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

About the Centre for Net Zero

Founded in 2021 by renewable energy group Octopus Energy, the London-headquartered Centre for Net Zero is a non-profit, impact-driven energy research institute providing policymakers with innovative data analysis and research to propel the energy transition into reality. The Centre’s team of 20 academics and policy experts operates autonomously and is led by computational chemist-turned-Whitehall policymaker Lucy Yu.