The energy industry has proven unpredictable over the past few months, with challenges ranging from rapid weather changes to gas supply shortages. One of the most pressing issues for many UK households and businesses is the continually rising energy costs that seem unlikely to come down any time soon.

While tackling this pressing concern, the government needs to look towards greener, more sustainable heating systems that will contribute towards the UK’s goal to achieve net zero by 2050.

One such solution lies in heat pumps which, when combined with low-global-warming-potential (GWP) refrigerants such as hydrofluoroolefins (HFOs) for example, will provide much-needed cost savings during this energy crisis, as well as offer an eco-alternative to the gas boilers predominantly in use today. As a reliable method to heat households and buildings, heat pumps are rightfully seen to be vital to a sustainable future and to reduce overall costs.

Energy used by heat pumps can be between 50% and 80% renewable, since they reuse energy from external environments to produce heat. These percentages become more significant when we compare them with a more commonly used direct electrification system, such as boiling an electric kettle. This action generates slightly less than one unit of heat for every unit of electricity put into it, whereas a heat pump generates between three and five units of heat for every unit of input electricity.

Another opportunity lies in scaling the process to provide heating to a neighbourhood of homes and buildings through district heating networks. Using a central heat source, such as heat pumps, district heating networks produce and deliver hot water or steam to provide heating for a number of building types. This method delivers reduced costs for users as well as the same energy efficiency seen in single-building heat pumps.

A tried and trusted solution  
District heating is far from new, having been in use around the world for the past 150 years. However, its popularity in the UK has only recently risen, with 17,000 heat networks, according to the Association for Decentralised Energy, connecting half a million consumers to a heat source in recent years. This number shows a great increase in interest in the system, as figures from 2013 found that only 2,000 networks had been installed.  

Studies estimate that district heating usage will grow by around 6% per year in Europe between now and 2027 which, if true, will be positive news in helping governments achieve their environmental goals. Using less energy than seen in other common building-heating methods, such as gas boilers, a rise in district heating networks will bring a lower carbon footprint and energy savings. These savings are multiplied when combined with high-efficiency electric heat pumps powered by low-GWP HFO refrigerants.

Using a central heat source, such as heat pumps, district heating networks produce and deliver hot water or steam to provide heating for a number of building types.

Heating the nation for less  
One of the main stumbling blocks we have seen in transitioning to heat pumps is the initial installation costs. However, with strong commitments made to achieve net zero in the UK, support from the government to further encourage the rollout of heat pumps will be vital.

Recent government initiatives include a plan to fund district heating network projects across south England. With this fund, £54mn has been awarded to four heat network projects, allowing around 28,000 homes and businesses to benefit from lowered energy bills while also reducing their dependence on fossil fuels. Based on the government’s findings, these four projects will result in annual carbon savings equivalent to taking more than 5,500 cars off the road.

To continue the momentum of government support, ‘money talks’ has to ring true where the return on investment for the everyday consumer must be measured and publicised. Once homeowners and businesses can better understand the end result, this will bring confidence and, in turn, increase the uptake of heat pumps and further district heating projects.

Along with a fund for district heating, the government has committed £450mn to encourage homeowners to install electric heat pumps to replace their current heating systems over the next three years. However, when we break this down, this would offer a grant of £5,000 to just 90,000 households over three years, which only equates to 30,000 homes a year. To meet the climate goals set, this is not enough.

Where funding may lack, however, education of the positive impact and returns of heat pumps will also play an important role in encouraging further adoption of heat pumps.

The success of district heating   
There are several examples currently showcasing the positive impacts seen from transitioning to heat pump technology in the UK. One is the London Borough of Southwark which, after declaring a climate emergency in March 2019, embarked on a district heating network project to achieve its goal of becoming carbon neutral by 2030. To meet this pledge, the Council sought to decarbonise its gas-powered heat networks that supply 17,000 council homes in the area and replace them with high efficiency electric heat pumps.

Plans for decarbonisation involved adding more insulation to the homes, using more energy from waste via the nearby South East London Combined Heat and Power (SELCHP) plant in Lewisham, and installing heat pumps as an alternative to gas boilers.

However, the challenge here was to ensure the cost associated with heat pumps did not fall on residents who would be unable to support the increased price. A solution was found in public funds provided to the Council, such as the Mayor’s Energy Efficiency Fund (an EU-backed low interest loan) and the UK government’s Renewable Heat Incentive, which helped to cover costs.

Tower Bridge connects the London Borough of Southwark with the Tower Hamlets.

Photo: Getty Images

Leading on the project, Vital Energi and its partners ICAX and J&E Hall collaborated to design and install four bespoke 600 kW heat pumps and one 1 MW heat pump in three existing plant rooms. Ensuring energy efficiency for the heat pumps, Honeywell supplied its own low-GWP Solstice N15 (R-515B) refrigerant, meeting regulations and requirements for cost, safety and efficiency.

Solstice N15 is capable of supporting temperatures up to 100°C – well above the Council’s regular operational temperatures of 75–80°C – while providing assurance for safe usage. The HFO-based refrigerant also offers low complexity and high efficiency with its lower-GWP, helping to decrease both overall costs, as well as CO₂ emissions typically seen from the network – providing a viable return on investment.

The refrigerant allows for flexibility throughout the installation of the project, with the heat pumps being situated close to the gas boilers. As it was compatible with existing pipework, this limited the need for reconstruction of the heating network which would disturb the day-to-day life of residents.

This project has resulted in reduced carbon emissions for over 2,000 council homes which, while helping to lower the heating bills of the residents, is also beneficial to our planet.

The secret lies in the refrigerant  
Heat pumps are beginning to become the preferred choice for the UK’s heating infrastructure, with upcoming government legislation including a ban on new gas boilers in newly built homes after 2025.

As used in the Southwark heating network, Solstice N15 is an example of an HFO technology that is part of Honeywell’s response to legislative demands to phase out hydrofluorocarbons (HFCs), as well as to accelerate the use of heat pumps.

Compliant with Europe’s Fluorinated Greenhouse Gases Regulations (EU F-Gas Regulation/GB F-Gas Regulation), refrigerants such as Solstice N15 play an important part in helping the UK and European Union to achieve their climate goals. They help reduce fossil-fuel use and electricity grid demand because they have higher energy efficiency, lower carbon emissions, lower total cost of ownership and are safer for use in heat pumps, including in densely urbanised areas or large-scale district heating networks.

Honeywell has invested more than $1bn in research, development and new capacity for its Solstice HFO technology, which is helping to avoid the potential release of the equivalent of more than 295mn tonnes of CO₂ into the atmosphere.

A promising start to a positive change  
Reflecting on the progress seen in district heating projects thus far in the UK, there is every sign that home and building heating will experience a large shift towards safer and more sustainable heating systems. With an increase in testimonies to its benefits, the uptake of heat pumps is indeed on the rise; however, we are still only at the start of a long journey that is needed to achieve carbon neutral goals. 

With support from the government and local councils to offset the initial cost – a critical factor commonly dissuading adoption – the incentive for heat pumps only becomes clearer and what may seem like a drastic change to a long-standing system is the innovation needed to unlock a dependable and affordable future in heating.