Heat zoning in the City of London

As the UK intensifies its climate efforts, heat networks are emerging as a cornerstone solution for decarbonising urban heating, addressing the 37% of national carbon emissions generated by building heating.

These systems distribute heating and sometimes cooling from a central source to multiple buildings via insulated pipes and can integrate diverse low-carbon heat sources, offering a scalable approach to reducing emissions.

Currently supplying just 3% of the UK’s heating demand, the government aims to expand this to 20% by 2050, requiring a £100 billion investment. Half of this growth could occur in London, serving 5 million customers nationwide and creating circa 300,000 jobs.

According to the Heat Network Industry Council, heat networks could deliver annual CO2 savings of 15 million tonnes by 2050—equivalent to a 9% reduction in the UK’s total heating emissions—while also improving air quality and resource efficiency.

Upcoming heat zone regulations will play a pivotal role in achieving this growth, in high-density urban areas. These regulations, expected in early 2026, will designate zones where district heating is the most cost-effective decarbonisation solution, mandating its adoption.

This approach addresses challenges like high upfront costs and fragmented markets. UK cities could follow the example of Malmö, where 95% of its 350,000 residents benefit from a low-carbon heat network managed by E.ON in co-operation with the municipality.

This system integrates energy-from-waste, biogas, and heat pump technology linked to sewage treatment, showcasing the transformative potential of heat networks for sustainable urban living.

The Department for Energy Security and Net Zero’s (DESNZ) Advanced Zoning Program (AZP) seeks to accelerate the adoption of zoning through pilot schemes, with construction targeted to begin in 2026.

A typical zone is expected to represent an investment opportunity of approximately £1 billion. One such pilot includes the City of London, with the potential to connect around 1,000 buildings. To align with forthcoming regulations, building energy strategies should prioritise assessing heat zone connections and the advantages of low-carbon heat supply that operators will be required to deliver.

E.ON operates the Citigen heating and cooling network in the City of London situated in the former Port of London Authority building. The network serves 28 buildings via an 11-kilometre insulated pipe network, recent expansions include the New Museum of London in Farringdon.

Citigen’s development has offered valuable insights into the unique challenges of implementing and expanding heat networks in one of the world’s most densely developed areas. Congested streets make installing miles of pipework over the next 15 years a significant logistical challenge, emphasising the need for collaboration with local authorities, utility providers, Transport for London (TfL), Network Rail, and the Greater London Authority (GLA).

To minimise disruption, construction efforts should align with Public Realm projects, such as pedestrian and cycle lane improvements, sustainable drainage systems, and London’s Healthy Streets program. This integrated approach maximises infrastructure benefits while reducing impacts on residents and businesses.

Zoning for heat networks also presents an opportunity to address London’s £40 billion investment potential while creating thousands of skilled local jobs. By collaborating with local authorities, schools, colleges, and initiatives like Skills for a Sustainable Skyline, the industry can build a pipeline of talent to meet future demands.

At the building level, connecting to a heat network involves installing heat exchanger infrastructure, typically in the building plant room where the existing gas boilers are found. This setup requires less space than traditional gas boilers, freeing up valuable commercial or operational areas. Additionally, reducing reliance on rooftop air source heat pumps creates opportunities for green roofs, solar panels, or recreational spaces.

Heat networks are pivotal to decarbonising urban heating, offering solutions to significant building emissions while delivering economic, environmental, and social benefits.

Achieving this vision requires overcoming logistical, regulatory, and workforce challenges through strategic collaboration, innovative zoning regulations, and substantial investment in skills and infrastructure. With heat zone regulations approaching, stakeholders must proactively prepare for the opportunities and challenges ahead.

This article was originally published in New London Quarterly - New London Architecture