Regulations: heat networks (metering and billing)
Guidance for heat suppliers.
Heat networks are systems in which heating, cooling or hot water is generated at a central source. The central heat source can use any type of technology and is supplied by the operator to third party customers through a pipe network.
Update February 2026: New Regulations for Heat Networks in Great Britain
The Heat Networks (Market Framework) (Great Britain) Regulations 2026 were introduced on 27 January 2026.
To prevent duplicate obligations on heat suppliers, this included a partial revocation of the Heat Network (Metering and Billing) Regulations (HNMB Regulations) in Great Britain.
Under the new Regulations, Ofgem have assumed their role as the regulator for heat networks, which provides protection for heat network consumers.
Heat networks are required to:
- meet the authorisation conditions
- register with Ofgem via a new digital service launching in spring 2026
For information on how the regulations apply, visit the Ofgem Heat Networks webpages.
Role of the Energy Ombudsman
Since 27 January 2026, all heat networks in Great Britain are subject to Ofgem regulation and must register with the Energy Ombudsman Redress scheme.
For more information and to register, visit the Energy Ombudsman site:
Through the Energy Ombudsman scheme, heat network consumers in Great Britain can access a free and independent dispute resolution service, if complaints are not satisfactorily resolved with a supplier, including complaints about unplanned outages which may lead to consumer compensation.
The Heat Network (Metering and Billing) Regulations
The HNMB Regulations, which initially came into force in 2014, aim to:
- provide consumer protections through requirements on heat network performance and consumer information
- improve energy efficiency through the installation of metering devices and billing based on consumption
- support fair and transparent billing for customers on heat networks
- support decreased use of energy, resulting in associated carbon emission savings*
*Note: EC commissioned research indicates the potential for savings of up to 20% of energy used by installing heat meters and other control devices.
The HNMB Regulations led to the creation of the first database of UK heat networks.
Under the HNMB Regulations, heat suppliers of heat networks must submit notifications for the heat networks they operate. They must install metering devices on those networks, unless it is not technically or financially feasible.
Heat suppliers whose networks are fitted with metering devices must meet ongoing obligations including using these devices to bill customers based on their consumption of heating, cooling or hot water, and ensure they are accurate and continue to operate efficiently.
What the Regulations cover
The HNMB Regulations describe 4 main components of a heat network:
- it must provide a shared source of heat for multiple users
- the heat transfer medium must be water, steam or chilled liquids
- the heat must be used for heating, cooling hot water or processes
- the heat must be sold to final customers by heat suppliers
Extent of obligation
The HNMB Regulations place obligations on heat suppliers.
A heat supplier is defined as any person or organisation that supplies and charges for the supply of heating, cooling or hot water to customers through a heat network or communal heating.
It is important to note that a heat supplier is a different concept from a fuel supplier.
A fuel supplier provides a source of fuel (such as gas or electricity) into a heat network’s energy centre but may not be involved in using that fuel to generate heating, cooling or hot water, or providing the heat generated to final customers.
A heat supplier has responsibility for operating a network to generate heating, cooling or hot water, and distribute this supply to customers.
Where multiple parties are involved in running a network, the heat supplier is the beneficiary of the customers’ payments. Typically, this is the party using customers’ payments to keep the network running.
See:
How to comply in Great Britain (England, Wales and Scotland)
The changes introduced by the 2026 amendment to the regulations mean that for heat suppliers in Great Britain:
- the duty to notify and the use of the cost-effectiveness tool* have been revoked
- there is no longer a requirement to send notifications to the HNMB Regulations Authority
*Note: The HNMBR cost-effectiveness tool is no longer applicable in Great Britain. In Northern Ireland, the tool is required to determine meter installation is cost-effective and whether a heat supplier has an obligation to install heat metering.
Heat suppliers in Great Britain should now comply with Ofgem’s Authorisation regime set out in the Heat Networks (Market Framework) (Great Britain) (Amendment) Regulations 2026.
When the Ofgem digital platform is launched in Spring 2026, Authorisation Conditions will require heat suppliers in Great Britain to provide information on the status of their networks to Ofgem:
- Ofgem will publish further information on this in due course
- draft guidance is available in this Ofgem consultation: Heat networks regulation: registration guidance
Changes to building classifications and the cost-effectiveness tool
The building classes defined under the HNMB Regulations have changed for heat suppliers in Great Britain. The classes are:
- Viable – meters must be installed
- Open – meters must be installed if the result of a cost-effectiveness assessment was positive before the 2026 amendment
- Exempt – meters do not have to be installed
From January 2026 the “Open” classification has been revoked, which simplifies the requirement to install a meter to only those that:
- are viable
- were already required to install as an outcome of a former assessment in the open class
This removed the requirement to use the cost-effectiveness tool, and prioritises meters as we transition to technical standards.
Heat suppliers in Great Britain with buildings in the open class, where a cost-effectiveness assessment determined that it was not cost effective to install meters, are no longer required to repeat that assessment within 4 years of the assessment having been carried out.
For not yet operational networks that:
- completed a cost-effectiveness assessment before 27 January 2026
- identified that they are required to install metering
- have not yet carried out installation
the obligation to install heat meters remains.
This does not extend to Heat Cost Allocators (HCAs) which can no longer be used to demonstrate compliance with the obligation to install meters under HNMB Regulations in Great Britain.
Heat suppliers in Great Britain with operational networks which were already supplying customers before 27 January 2026, are required to:
- maintain meters where they are already present on networks supplying heating, cooling or hot water to customers
- register with the Ofgem digital service when it is launched in Spring 2026
New networks should be ready to register with Ofgem before commencing supply of heating, cooling and hot water to customers.
Until the launch of the Ofgem digital service, we will continue to set out how non-compliance will be addressed.
Enquiries on forthcoming registration can be sent to Ofgem via: heatnetworksregulation@ofgem.gov.uk
Heat suppliers, network operators and industry professionals should:
- stay informed about the development of heat network technical standards regulations
- provide feedback as these evolve
- be aware of the regulatory direction of travel: Heat Network Technical Assurance Scheme (HNTAS)
How to comply in Northern Ireland
Heat Network (Metering & Billing) Regulations 2014 and 2020 obligations are unaffected, and will remain in force in Northern Ireland.
Heat suppliers in Northern Ireland should:
- continue using the cost-effectiveness tool
- provide notice to the Department for Energy Security and Net Zero (DESNZ)
Heat suppliers that are ready or due to submit a notification must email the DESNZ team at HN.Meters@energysecurity.gov.uk.
DESNZ will respond to your email with a link to a secure zone for you to upload your notification.
You should read the user guide before completing the notification template:
The HNMB Regulations continue to have effect in Northern Ireland until they are repealed, replaced or amended. The Northern Ireland Department for the Economy (DfE) is developing proposals for a future regulatory framework. Further details will be announced in due course.
DESNZ involvement
The Department for Energy Security and Net Zero has assumed responsibility for receiving and processing heat network notifications in Northern Ireland. This includes (where relevant):
- pursuing notification submissions
- verifying that metering devices are installed, accurate and operating correctly
- verifying that billing requirements are met
The Department also assumed responsibility for enforcement of HNMB Regulations across Great Britain (for remaining regulations) and Northern Ireland on behalf of the Secretary of State.
We will continue assess and address non-compliance by those we regulate under the HNMB regulations.
Find out more
- Heat Network (Metering and Billing) Regulations 2014
- Heat Network (Metering and Billing) (Amendment) Regulations 2015
- Heat Network (Metering and Billing) (Amendment) Regulations 2020
- The Heat Networks (Market Framework) (Great Britain) (Amendment) Regulations 2026
Contact us
If you have a specific enquiry about compliance or wish to contact us regarding suspected non-compliance:
- Email: HN.Meters@energysecurity.gov.uk
- Write to:
3–8 Whitehall Place
London
SW1A 2EG