Heat network technical regulation is coming. Are developers and building operators ready?

Another significant regulatory change is set to reshape the heat network sector and, compared with the Building Safety Act, remarkably little attention is being paid to it by many developers and building operators.

The Heat Network Technical Assurance Scheme (HNTAS), together with its accompanying Technical Standard, TS1, will fundamentally change the way both new and existing heat networks are designed, constructed, commissioned, assessed and operated.

This technical regime also sits within a much wider change in the regulatory landscape. Ofgem became the regulator for heat networks in Great Britain in January 2026, introducing authorisation conditions and consumer protection requirements for operators and suppliers. At the same time, heat network zoning is developing in England, with particular significance for London and other dense urban areas.

This is not just another technical standard – we are moving from a system based largely on voluntary good practice to one in which performance and compliance will increasingly need to be demonstrated, independently assessed and evidenced.

That changes the risk considerably, and it applies to existing operational networks as well as projects still on the drawing board.

The industry is underestimating this. I have seen the scale of the problem firsthand, and developers and building operators would be making a mistake if they treated 2027 as the point at which they need to start addressing it.

Whether you are delivering a new development containing a heat network or responsible for an existing portfolio, now is the time to understand what you have, what the emerging requirements mean and where the gaps are likely to be.

Until now, the industry benchmark for technical performance has been CIBSE’s CP1 Code of Practice for heat networks. Good consultants and operators have already been designing and managing networks around many of its principles.

TS1 builds on much of that engineering thinking. The significant change is not necessarily what engineers are being asked to achieve. It is how developers and operators will have to demonstrate that they have achieved it – and continue to achieve it during operation.

Under HNTAS, technical assurance is intended to be independently assessed, with defined evidence requirements. For new networks, that means assurance through design, construction and commissioning. For existing networks, the draft framework takes a milestone-based approach, recognising that operational systems start from very different positions and may need time and planned interventions to reach the required level of performance.

That distinction matters. Under the existing approach, an experienced engineer might be able to confirm that a system has been designed or is operating appropriately. Under the emerging regime, organisations will need a much more structured evidence trail to demonstrate conformity with the relevant requirements. This is no longer solely a maintenance issue: it is part of a formal regulatory and asset-management responsibility.

The obvious concern is programme and operational risk. Independent assessment capacity will be needed, evidence must be assembled, and shortcomings may have to be addressed. As with any new regulatory system, there are likely to be teething problems.

The answer is to build HNTAS into project programmes for new schemes while, in parallel, auditing existing networks and planning the route to compliance. Treating either as something to be dealt with at the end is likely to create unnecessary cost and risk.

New development and existing stock face different technical challenges, but neither should be treated as secondary.

For a new network, the advantage is that the emerging requirements can be considered from the outset. There will inevitably be additional costs. More extensive metering, consultancy, assessment and evidence requirements all have implications for project budgets. But designing for compliance is invariably easier than trying to retrofit it later.

Metering is a good example. If I were advising on a new system being designed today, I would be looking very closely at the metering and monitoring requirements. Installing the right infrastructure during construction is relatively straightforward.

The same principle applies to equipment selection, insulation, commissioning and testing. TS1 moves towards more performance-based requirements in areas such as heat loss, while commissioning, monitoring and witnessed testing become increasingly important. Product choices that might previously have been regarded as standard need to be reviewed against the emerging requirements.

Waiting until commissioning to discover that a heat interface unit, pipework specification or another part of the system does not deliver the required performance is an expensive way to find out.

Existing networks present a different challenge. In London alone networks vary enormously in age, design, condition, metering and efficiency. Some are relatively modern; others have been operating for many years.

The draft HNTAS approach for existing networks reflects that reality. Some systems may require relatively modest interventions to improve monitoring, evidence or controls. Others could need significant physical improvement and a longer-term performance improvement plan.

In my previous role, I managed a portfolio of 14 London-based heat networks, some of which may require work under the emerging regulatory regime

Multiply that across London’s residential, commercial and mixed-use stock – and across the UK’s larger portfolios – and the scale of the asset-management task becomes apparent.

Crucially, works to existing systems must often take place in occupied buildings. That raises questions about access, disruption, budgets, consultation with residents and, potentially, recovery of costs. This is why owners and operators need to establish their exposure now, rather than waiting for technical compliance deadlines to arrive.

HNTAS should not be viewed in isolation. Ofgem is now the regulator for heat networks in Great Britain, and the consumer protection regime is already live. Operation of heat networks requires authorisation, and relevant operators and suppliers must register their networks with Ofgem by January 2027.

That matters because it reinforces the direction of travel: heat networks are becoming regulated utilities rather than relatively lightly governed building services. For building operators in particular, technical performance, reliability, customer service, pricing and regulatory accountability increasingly sit within the same overall picture.

The consumer is at the heart of the change. Unlike most domestic gas or electricity customers, somebody living in an apartment connected to a communal heat network generally cannot simply change supplier if they are unhappy with the service or price. The efficiency and reliability of the network therefore have a direct effect on the service residents receive and what they pay.

Poorly designed or poorly operated systems can waste significant amounts of energy. Historically, engineers might have built additional capacity into systems as a safety margin. The tendency now is to design and operate networks more closely around actual demand, demonstrable efficiency and measurable performance.

And crucially, that efficiency needs to last. The proposed technical assurance regime is not simply concerned with how a network performs on the day it is commissioned. Ongoing monitoring and later assessment mean that operation is just as important as design.

Networks therefore increasingly need to be managed by organisations with the specialist knowledge, information and governance required to keep them performing efficiently throughout their lives.

Heat network zoning is the other important piece of the puzzle, particularly for London.

The Energy Act 2023 provides the powers to designate heat network zones in England: areas where they are expected to provide the lowest-cost, low-carbon option for heating buildings. The government is developing the implementation framework, and London is already deeply engaged in the process through the GLA, London boroughs and early zoning work.

Zoning is intended to create greater certainty around heat demand and network development. Within designated zones, certain new buildings, existing communally heated buildings and qualifying non-domestic buildings may be required to connect, subject to the final regulations and exemptions.

For developers, this can affect the heating strategy for future schemes. For owners and operators of existing buildings, it means the question may not simply be whether an existing communal network can meet HNTAS requirements, but how that asset fits into a wider zonal network over time.

In London, where existing networks range enormously in age and condition while major new district networks are also being planned, technical assurance, Ofgem regulation and zoning need to be considered together rather than as separate policy initiatives.

There is still some uncertainty around the final form and implementation of HNTAS and TS1, and the detailed zoning framework is continuing to develop. But that is not a reason to do nothing.

We know enough to begin preparing. The underlying principles are clear: greater accountability, independent technical assurance, better metering and monitoring, demonstrable performance, stronger evidence and much closer scrutiny of how networks perform throughout their lives.

For developers, owners and operators, I would start by reviewing both the existing estate and the development pipeline.

Which buildings contain heat networks? Who is legally and operationally responsible for them? What condition are they in? What information exists on their performance? Is appropriate metering and monitoring already installed? What stage are pipeline projects at? Could any assets or proposed developments fall within emerging heat network zones? Where are the obvious gaps between current arrangements and the new requirements?

A desktop gap analysis can identify where the greatest risks lie and distinguish between relatively inexpensive early interventions and networks that could require substantial redesign, refurbishment or a longer-term improvement plan.

Organisations should also decide who has responsibility internally. Leaving individual project teams, facilities managers or managing agents to interpret the requirements independently risks inconsistent approaches across the same portfolio. A coordinated strategy covering development, operation and asset management is far more sensible.

The precise shape of HNTAS, TS1 and zoning will continue to develop. But the fundamental direction is not going to change.

Heat networks are moving into a much more formal regulatory environment. Ofgem regulation is already in place, mandatory technical assurance is approaching, and zoning will shape where and how networks expand.

For developers and building operators alike, that means additional responsibility, additional evidence and a need to incorporate heat network compliance into both project delivery and long-term asset-management programmes.