UK publishes draft TS1 technical standard ahead of heat network regulation
19 November 2025
The UK government has published its draft TS1 Heat Network Technical Standard, setting out the minimum technical requirements that will underpin the forthcoming regulation of heat networks across Great Britain.
The new standard replaces the voluntary CP1 Code of Practice (2020), transitioning the sector toward a formalised regime that will be overseen by Ofgem from 2026. DESNZ says CP1 provided a strong foundation but was applied inconsistently, leading to wide variations in build quality, consumer outcomes and network performance. TS1 aims to close that gap by establishing mandatory baseline requirements for design, installation and operation.
TS1 will act as the principal reference for the Heat Network Technical Assurance Scheme (HNTAS), created under the Energy Act 2023. HNTAS will assess networks against statutory technical standards, KPIs and verification procedures, with compliant schemes eligible for certification.
Heat networks currently meet around 2–3% of UK heat demand, supplying roughly 500,000 homes through around 12,000 schemes. But growth is accelerating: more than 50,000 heat interface units (HIUs) are installed annually, equating to around 500 new networks coming online each year. With government financial backing and regulation on the way, DESNZ expects that number to rise significantly as the UK pushes toward its ambition for heat networks to supply 20% of national heat demand by 2050.
The department warns that while many new-build networks already follow CP1, implementation is mixed, and too many systems still fail to deliver reliable, low-cost, low-carbon heat. Oversizing, poor design and operational inefficiencies continue to undermine both consumer outcomes and investor confidence – issues TS1 is designed to fix.
Tom Burton, principal engineer at FairHeat, welcomes the new draft, calling its publication “a landmark moment in the regulatory evolution of heat networks in Britain.” He says:
“Heating the nation’s 28 million homes is one of the largest sources of carbon emissions in the UK. Putting in place robust technical specifications will help unlock billions in private investment and support good consumer outcomes for millions of households decarbonising their heat supply.
“The development of the new TS1 framework has been made possible by the collective expertise of around 40 organisations and technical specialists, including social landlords and local authorities, who invested their time in workshops, roundtables and industry discussions.
“The new TS1 standards will work hand in glove with the upcoming Heat Network Technical Assurance Scheme (HNTAS) to deliver a well-regulated and highly investable heat network sector which will provide reliable, efficient and affordable decarbonised heat for consumers.”
