Ofgem regulation, HNTAS and what operators must do by 2027

Most of this site is about heat network zoning, which is still on its way. This guide is about something different that is already law. Since January 2026, Ofgem has regulated heat networks, and that applies to many organisations that have never thought of themselves as heat suppliers: housing associations, landlords of blocks with a shared boiler, universities and hospitals running site networks, and the operators of district heating schemes. If that might be you, there is a deadline in January 2027 you need to know about.

Regulation and zoning are separate things

It's easy to blur the two, so here is the distinction.

Zoning is about where heat networks get built and which buildings must connect. It applies to England only[source], and the regulations to make it work are not yet laid before Parliament[source].

Regulation is about how heat networks are run once they exist: how customers are treated, billed and protected, and in time how well the networks are built and maintained. It applies across Great Britain, so a communal heating system in Glasgow or Cardiff is covered as well as one in Manchester. And it is in force now.

You can be affected by one without the other. A landlord of a single block with a communal boiler in a town with no zoning plans is regulated today, with no zoning in sight.

What changed in January 2026

Before this date, heat network customers had no dedicated regulator. Gas and electricity customers have long had Ofgem and a set of supply rules behind them. People whose heat came from a communal or district system mostly did not, which left them reliant on their lease or contract when things went wrong.

The regulations that set up the new framework are the Heat Networks (Market Framework) (Great Britain) Regulations 2025. Under them, Ofgem sets authorisation conditions that operators must follow. We don't summarise the conditions here, because the detail matters and Ofgem publishes them in full. Read them on Ofgem's heat networks pages, or ask a specialist to check your arrangements against them.

The registration deadline

The date that most operators need to plan around is this one:

Registration means telling Ofgem who you are and which networks you run. That sounds simple, but for a large landlord it can mean a real piece of work: finding every building with shared heating, working out who actually runs each system, and gathering basic information about each one. Leaving it until January is a bad idea, particularly for organisations with lots of buildings or messy records.

What happens if you miss the deadline isn't something we have set out here. Ofgem's own guidance is the place to check, and it's far easier to register on time than to find out.

Who counts as an operator

This is the question that catches people out. The likely answer is broader than many expect.

A heat network, in the regulatory sense, is broadly a system where a central source supplies heat or hot water to more than one building or to more than one customer in a building. That covers large district heating schemes, but it also covers a block of flats with a single plant room feeding every flat.

So landlords and managing agents who run a communal system are likely to count as operators, even if heat is recovered through a service charge rather than a separate bill. The same goes for housing associations, councils, universities with halls of residence, and NHS trusts with site networks serving third parties. Where a system is run by a contractor or energy services company on your behalf, the question of who holds the regulatory responsibility depends on the arrangements, and contracts may need looking at.

We'd frame all of this as "likely". Ofgem decides who is in scope, and its guidance sets out the tests and any exceptions. If you aren't sure, read it carefully, and take legal advice where leases or contracts are involved.

Consumer protection: Citizens Advice and the Energy Ombudsman

Consumer protection for heat network customers actually started before Ofgem took over.

The consumer advocate is Citizens Advice, for heat network consumers in England and Wales[source]. That means residents who are unhappy with their heat supply can get free, independent advice. Customers in Scotland should check Ofgem's site for the advice routes that apply to them.

For disputes, the Energy Ombudsman accepts heat network disputes, usually after 8 weeks with the supplier[source]. In practice, that means a customer who complains to you and isn't satisfied can take the complaint further. Your own complaints process should be clear, quick and well recorded, and it should tell people where they can go next.

For operators, this changes the dynamic. A dispute about heat charges that might once have stayed between landlord and tenant can now go to an independent body. Good records of how charges are calculated, and good metering, are your best defence.

Metering and billing rules got simpler

Alongside the start of regulation, the older metering and billing rules were trimmed.

These are the Heat Network (Metering and Billing) Regulations 2014, which many operators have struggled with for years. The changes take away some duties, but they don't remove the rules entirely. If you previously planned work purely to meet a requirement that has since gone, such as fitting heat cost allocators, check whether it is still needed before you spend money. If you bill customers on actual use, meters still need to be accurate, read and maintained.

Our directory lists specialists in metering and billing who can check your current arrangements.

HNTAS: technical standards on the way

The third part of the picture is the Heat Network Technical Assurance Scheme, usually shortened to HNTAS.

As the name suggests, HNTAS is about technical assurance: checking that heat networks are designed, built and run to minimum technical standards. Poor design and maintenance are often blamed for some of the worst customer outcomes on older networks, such as high bills, frequent outages and overheated corridors. HNTAS is the government's answer to that.

The details of which networks are assessed first, what the assessment involves and how much it costs are set out, as they firm up, on the GOV.UK HNTAS page. Because the scheme is phased in, the date it starts to apply to your network may not be the launch date. For now, the useful thing to do is understand your network's condition. Do you have as-built drawings, operating and maintenance manuals, commissioning records and performance data? If not, gathering them now will help whenever HNTAS reaches you. Specialists in HNTAS readiness can help.

A checklist to January 2027 and beyond

Here's a practical plan, working back from the registration deadline and forward to HNTAS.

This quarter (November and December 2026). Build a list of every system you own or manage that might be a heat network. For each, note the address, the number of homes or units it serves, who runs it day to day, and how customers are charged. Read Ofgem's guidance on scope and registration. Decide who in your organisation owns the job. If your portfolio is large or complicated, appoint help now, because specialists will be busy in the run-up to the deadline. Our directory lists firms offering Ofgem authorisation support.

January 2027 (before the 26th). Complete registration for every network in scope. Keep a record of what you submitted and when. Don't leave the last network until the last week.

First half of 2027. Check your day-to-day practice against the authorisation conditions, which have applied since January 2026. Review your complaints process, including signposting to Citizens Advice and the Energy Ombudsman. Look at how heat charges are calculated and explained to customers, and whether your metering supports that.

Second half of 2027. Track HNTAS as it launches and find out when your networks come into scope. Pull together technical records and consider a condition survey of older systems, which also informs any capital plan.

Getting help

For a small landlord with one block, much of this can be done in-house with care. For a larger portfolio, or where contracts and leases are tangled, heat network consultants with regulatory experience can save a lot of time. Our guide to choosing a consultant explains what to look for, and our operator listings show who runs networks. If you are also in an area where zoning is coming, our zoning explainer covers that separate regime.