Heat Trust reports record customer debt as voluntary scheme passes 93,000 consumers

Heat Trust, the voluntary consumer-protection scheme for communal and district heat networks, said on 5 November that the share of its customers more than two months in debt reached a record high of over 25% by September 2025.

The figure comes in the scheme's report on its ninth and tenth years of operation, covering October 2023 to September 2025. Heat Trust said 93,637 consumers were protected at the end of September 2025, 18,400 more than in October 2023, and that the total is now close to 100,000.

The report also records what Heat Trust called "far too frequent" supply interruptions, with average performance across the scheme appearing to worsen over time and a wide gap between the best and worst sites.

Stephen Knight, Chief Executive of Heat Trust, said: "Our unique monitoring data shows that heat network customers continue to experience far too many supply outages". He added that, after years of high gas prices pushing heat prices up, a larger proportion of heat customers are in debt than ever before.

Growth ahead of regulation

Heat Trust said 28 new heat networks were registered across 12 heat suppliers during the period, five of them joining the scheme for the first time. Sector coverage has also spread geographically, with 34 registered sites now outside London.

The scheme attributed the growth to operators preparing for statutory regulation. According to the Department for Energy Security and Net Zero (DESNZ), the Heat Networks (Market Framework) (Great Britain) Regulations 2026 came into force on 27 January 2026, making Ofgem the regulator of all heat networks in Great Britain. Operators must register with the Energy Ombudsman Redress scheme and with Ofgem through a new digital service launching in spring 2026, DESNZ said.

Heat Trust said both Ofgem and DESNZ had encouraged suppliers to "follow existing good practice, such as that set out by the Heat Trust", and that registration with the scheme remains the best way for suppliers to demonstrate compliance and good practice.

Reliability and standards

For building services engineers and operators, the reliability findings carry a regulatory message. Heat Trust said the site-by-site range in performance underlines the case for including Guaranteed Standards of Performance (GSOPs) and a technical assurance scheme in the incoming framework, and that both remain work in progress.

Other findings in the report, according to Heat Trust:

• Winter 2023-24 saw the highest rate of winter supply disconnections, mainly used for debt, since before Covid-19. The rate of suspensions rose to a high of six in every 1,000 customers over the period.
• More vulnerable customers are being identified. The proportion on Priority Service Registers rose to 11.7% by September 2025, compared with 4% in 2021.

Customers on Priority Service Registers	Share
2021	4%
September 2025	11.7%

Context

Heat Trust, operated by Heat Customer Protection Ltd, describes itself as independent and not for profit and has run its voluntary scheme since 2015, overseen by a non-executive board and an independent stakeholder committee. The scheme said it was set up to fill the gap left by the absence of statutory consumer protections for heat networks.

Heat Trust estimates that about 500,000 homes in the UK are currently on heat networks and that over five million could be served by 2050, with a third of new-build homes already connected. When the government announced the new regime on 26 January 2026, it said more than 500,000 heat network customers would be shielded from unfair price spikes. Martin McCluskey, Minister for Energy Consumers, said at the time that customers on heat networks had been unprotected for too long.

Anna Eagar, Heat Trust Board member and Non-Executive Director of Aberdeen Heat and Power, said the scheme had changed how government and industry think about customer protection.

Knight said Heat Trust would continue to maintain consumer protections while full statutory protections are phased in over the coming year or so.