Metering and billing terms Heat network glossary.

Authorisation conditions

The conditions that relevant heat network suppliers and operators must comply with.

Ofgem's guidance says: “Since regulatory commencement on 27 January 2026, relevant heat network suppliers and operators have been required to comply with the recently published suite of authorisation conditions.” (Ofgem, Heat networks: regular data reporting, published 10 March 2026, Introduction.) Ofgem's guidance says: “These conditions include key areas of consumer protection such as billing, complaints, vulnerability and debt as well as the financial resilience of authorised persons.” (Ofgem, Heat networks: regular data reporting, published 10 March 2026, Introduction.)

Authorised person

Ofgem's guidance says: “An authorised person is an entity that is authorised to undertake one or both regulated activities in relation to a heat network under regulation 16 or regulation 27 of the regulations.” (Ofgem, Heat networks registration, version 1.0, published 23 January 2026, paragraph 2.5.)

Automatic meter readingAMR

Collecting meter readings remotely and automatically, without visiting the meter.

Back-billing

Billing a customer for heating, cooling or hot water used in the past.

Ofgem's guidance says: “Ofgem regulation aims to prevent suppliers from back-billing heat network consumers for heating, cooling or hot water consumed more than 12 months prior to the date of the bill, in circumstances where the customer is not at fault.” (Ofgem, Heat networks regulation: consumer protection guidance, published 13 January 2026, paragraph 5.4.)

Building management systemBMS

The control system that monitors and runs a building's plant, such as boilers, pumps and valves.

Bulk meter

A heat meter that measures the heat supplied to a whole building or block, rather than to one home.

Deemed authorisation

Ofgem's guidance says: “Authorised persons that began operating or supplying a heat network before 1 April 2025 are automatically authorised under the regulations, referred to as ‘deemed authorisation’, and may continue these activities.” (Ofgem, Heat networks registration, version 1.0, published 23 January 2026, paragraph 3.6.)

Energy centre

The plant room where heat for the network is generated before it is pumped to the buildings it serves.

Energy service companyESCO

A company that runs or supplies a heat network on someone else's behalf.

Exception

A meter reading that fails a check, for example a missing, zero or implausible reading, and needs someone to look at it.

Heat interface unitHIU

The unit inside a home that transfers heat from the network to the home's own heating and hot water.

Heat loss

Heat that is generated but never reaches a customer's meter, for example heat lost from pipework.

Heat meter

A device that measures the heat energy delivered to a home or building, in units such as kilowatt hours (kWh).

Heat network

Ofgem's guidance says: “A heat network is a network that, by distributing a liquid or a gas, enables the transfer of thermal energy for the purpose of supplying heating, cooling or hot water to a building or persons in that building, and includes any appliance the main purpose of which is to heat or cool the liquid or gas.” (Ofgem, Heat networks registration, version 1.0, published 23 January 2026, paragraph 2.16.)

Heat Network (Metering and Billing) Regulations

The regulations under which heat network metering is currently regulated.

Ofgem's guidance says: “Currently, metering is regulated under the Heat Network (Metering and Billing) Regulations. New metering requirements will be set out in the Heat Network Technical Assurance Scheme (HNTAS).” (Ofgem, Heat networks fair pricing and cost allocation guidance, published 13 January 2026, paragraph 1.31.)

Heat Network Efficiency SchemeHNES

A grant scheme in England and Wales. See the scheme details on GOV.UK.

Ofgem's guidance says: “In England and Wales, the Heat Network Efficiency Scheme (HNES) funds the improvement of district and communal heating projects with particular focus on how funded projects reduce detriment for residential "customers in need".” (Ofgem, Heat networks regulation: consumer protection guidance, published 13 January 2026, paragraph 1.51.)

Heat network operator

The organisation that operates a heat network.

Ofgem's guidance says: “Operating a relevant heat network means controlling the transfer of thermal energy on that heat network for the purposes of supplying heating, cooling or hot water.” (Ofgem, Heat networks registration, version 1.0, published 23 January 2026, paragraph 2.6.)

Heat network supplier

The organisation that supplies heating, cooling or hot water to customers through a heat network.

Ofgem's guidance says: “An entity is undertaking the regulated activity of supply where they are responsible for the commercial arrangements with customers associated with the supply of heating, cooling, or hot water via a relevant heat network.” (Ofgem, Heat networks registration, version 1.0, published 23 January 2026, paragraph 2.11.) Ofgem's guidance says: “Commercial arrangements include setting charges, issuing bills, providing customer service and handling complaints.” (Ofgem, Heat networks registration, version 1.0, published 23 January 2026, paragraph 2.12.)

Heat Network Technical Assurance SchemeHNTAS

The scheme through which new heat network metering requirements will be set. It is being developed by the Department for Energy Security and Net Zero (DESNZ) and the Scottish government.

Ofgem's guidance says: “Currently, metering is regulated under the Heat Network (Metering and Billing) Regulations. New metering requirements will be set out in the Heat Network Technical Assurance Scheme (HNTAS).” (Ofgem, Heat networks fair pricing and cost allocation guidance, published 13 January 2026, paragraph 1.31.) Ofgem's guidance says: “For detailed technical standards and best practices, please refer to the forthcoming Heat Network Technical Assurance Scheme (HNTAS), which is being jointly developed by the DESNZ and the Scottish government.” (Ofgem, Heat networks fair pricing and cost allocation guidance, published 13 January 2026, paragraph 1.38.)

Non-disclosure agreementNDA

A contract in which the parties agree to keep shared information confidential.

OfgemOffice of Gas and Electricity Markets

The regulator for heat networks in Great Britain.

Ofgem's guidance says: “Ofgem is the designated regulator for heat networks in England, Scotland, and Wales (Great Britain).” (Ofgem, Heat networks registration, version 1.0, published 23 January 2026, Introduction.)

Outlier

A property whose heat consumption is unusually high, unusually low or zero compared with similar properties.

Standing charge

Ofgem's guidance says: “Standing Charge - means a monetary amount that is chargeable to a Consumer on a daily or other periodic basis and which is chargeable in addition to charges arising on the basis of a Unit Rate” (Ofgem, Heat networks: regular data reporting, published 10 March 2026, Appendix 2, A2.27.)

Supply meter

Ofgem's guidance says: “Supply Meter - means a meter used or to be used for measuring the quantity of heating, cooling or hot water supplied to a Consumer” (Ofgem, Heat networks: regular data reporting, published 10 March 2026, Appendix 2, A2.28.)

Tariff

The prices charged for heat. A heat tariff can include a unit rate and a standing charge.

Unit rate

Ofgem's guidance says: “Unit rate - means the price charged per unit of heating, cooling or hot water supplied to a Consumer” (Ofgem, Heat networks: regular data reporting, published 10 March 2026, Appendix 2, A2.29.)

Quoted Ofgem text is Crown copyright and contains public sector information licensed under the Open Government Licence v3.0. For the wider picture, see heat network regulation in plain English.