Glossary
The language of heat network zoning
67 terms used on this site and in government documents, defined in plain English. Regulatory terms link to the source that defines them.
A
- Advanced Zoning ProgrammeAZP
- Government funding and support for a smaller set of places to develop heat network zones ahead of the regulations. The first places were named in October 2024. Abbreviated AZP.See also: Heat network zoning pilot, Development partner. Source: Six towns and cities to pilot clean heating innovation (GOV.UK)
- Agreement period
- The time after a connection notice, at least six months, in which a building owner either agrees a connection date with the zone developer or applies for a temporary exemption.See also: Connection notice, Temporary exemption. Source: Proposals for heat network zoning: government response (GOV.UK, Jan 2026)
B
- Boundary consultation
- A public consultation by a council on where a proposed zone's edges should fall. Those held before the regulations are in force are preparatory and do not designate a zone.See also: Designation, Candidate zone
C
- Campus network
- A heat network serving one organisation's site, such as a university, hospital or business park. Government intends to extend zoning requirements to buildings containing an energy centre that supplies such a network.See also: Energy centre, Required building. Source: Proposals for heat network zoning: government response (GOV.UK, Jan 2026)
- Candidate zone
- An area identified in a study as a possible heat network zone. Candidate zones have no legal status and their boundaries may change before any designation.See also: Zone opportunity report, Designation
- Citizens Advice
- The statutory advocate for heat network customers in England and Wales since April 2025, offering advice and representing consumers' interests.See also: Energy Ombudsman, Consumer Scotland. Source: If your home is on a heat network (Citizens Advice)
- Code Manager
- The body that will run the Heat Network Technical Assurance Scheme. Government has proposed that its own department takes the role at first.See also: Heat Network Technical Assurance Scheme. Source: Heat network technical standards consultation (GOV.UK)
- Combined heat and powerCHP
- Plant, often gas-fired, that generates electricity and captures the heat for a network. Many older networks rely on it; newer ones are moving to lower-carbon sources.See also: Energy centre
- Communal heating
- A heat network inside a single building or block, where one boiler room or plant room heats every flat or unit. Existing buildings with communal heating are one of the categories that could be required to connect in a zone.See also: Heat network, Required building. Source: Proposals for heat network zoning: government response (GOV.UK, Jan 2026)
- Connection notice
- A formal notice from the zone coordination body telling the owner of a building in a designated zone that it is required to connect. It starts an agreement period of at least six months.See also: Agreement period, Connection window. Source: Proposals for heat network zoning: government response (GOV.UK, Jan 2026)
- Connection window
- The period, at least 12 months long, within which a required building must be connected to the zone's network. It can overlap with the agreement period.See also: Agreement period, Connection notice. Source: Proposals for heat network zoning: government response (GOV.UK, Jan 2026)
- Consumer Scotland
- The statutory advocate for heat network customers in Scotland since April 2025.See also: Citizens Advice. Source: Greater protections for heat network customers in Scotland (Consumer Scotland)
- Crown body
- A body that acts on behalf of the Crown, such as many central government departments. Zoning law does not currently apply to them, though government is exploring changing that.See also: Required building. Source: Proposals for heat network zoning: government response (GOV.UK, Jan 2026)
D
- Department for Energy Security and Net ZeroDESNZ
- The UK government department responsible for energy policy, including heat networks and zoning. Abbreviated DESNZ.See also: Heat Network Zoning Authority
- Designation
- The formal legal act that creates a heat network zone. It can happen only once the zoning regulations are in force, and no zone in England has yet been designated.See also: Heat network zone, Zoning regulations. Source: Proposals for heat network zoning: government response (GOV.UK, Jan 2026)
- Development partner
- A company a council has appointed, outside the statutory zoning process, to develop and often finance and run local heat networks. Several places have appointed one ahead of the regulations. Also called a delivery or development and funding partner.See also: Zone developer, Advanced Zoning Programme
- Distribution network
- The local part of the electricity grid that carries power to homes and businesses. Government modelling suggests more heat networks would reduce the cost of upgrading it as heating electrifies.See also: Heat pump. Source: Warm Homes Plan (GOV.UK)
- District heating
- A heat network serving many separate buildings across an area, such as a town centre or estate. In this site's usage it means the same as a heat network at area scale; district heating zones is a common synonym for heat network zones.See also: Heat network, Heat network zone
E
- Energy Act 2023
- The Act of Parliament that created the legal power for heat network zoning in England (Part 8, Chapter 2) and for Ofgem to regulate heat networks. It received Royal Assent on 26 October 2023.See also: Heat network zoning, Zoning regulations. Source: Energy Act 2023, Part 8, Chapter 2 (legislation.gov.uk)
- Energy centre
- The building that houses a heat network's main plant, such as heat pumps, boilers or heat exchangers drawing on waste heat, and pumps that push hot water round the pipes.See also: Heat network, Campus network
- Energy from wasteEfW
- Burning non-recyclable rubbish to generate electricity and heat. Several existing English networks, including in Sheffield, Nottingham, Coventry and south London, use heat from these plants.See also: Waste heat
- Energy Ombudsman
- The free, independent service that resolves complaints between energy customers and suppliers. It has taken heat network complaints since April 2025, usually once a complaint has been open for eight weeks.See also: Citizens Advice. Source: Heat networks (Energy Ombudsman)
- Exemption
- Permission for a building that would otherwise be required to connect not to do so, on grounds such as an existing low-carbon system, legal or physical barriers, safety remediation or conservation constraints.See also: Temporary exemption, Required building. Source: Proposals for heat network zoning: government response (GOV.UK, Jan 2026)
G
- Government response
- The document government publishes after a consultation, setting out what it heard and what it has decided. The January 2026 response sets out the final policy design for zoning.See also: Zoning regulations. Source: Proposals for heat network zoning: government response (GOV.UK, Jan 2026)
- Green Heat Network FundGHNF
- A government capital grant scheme for new and expanding low-carbon heat networks, covering less than half of eligible costs. Abbreviated GHNF.See also: Heat Network Efficiency Scheme, Heat Networks Investment Project. Source: Green Heat Network Fund guidance (GOV.UK)
- Guaranteed standards of performance
- Service standards with automatic compensation when a supplier misses them, as already exist for gas and electricity. Ofgem is developing them for heat networks; no start date is confirmed.See also: Ofgem
H
- Heat cost allocator
- A small device on a radiator used to share a building's heating bill between flats where each flat does not have its own heat meter.See also: Heat meter, Metering and billing regulations
- Heat demand
- The amount of heat a building uses over a year, measured in megawatt-hours. Large existing non-domestic buildings are expected to be required to connect only above a set threshold of heat demand.See also: Megawatt-hour, Required building. Source: Proposals for heat network zoning: government response (GOV.UK, Jan 2026)
- Heat interface unitHIU
- A compact unit in each flat or building that transfers heat from the network to the property's own radiators and hot water, and usually holds the heat meter.See also: Heat network, Heat meter
- Heat meter
- A device that measures how much heat a property takes from a network, so it can be billed for what it uses.See also: Heat interface unit, Metering and billing regulations
- Heat network
- A system of insulated pipes that carries hot water from one or more central heat sources to several buildings, instead of each building having its own boiler. Also called district heating when it serves a neighbourhood or town.See also: District heating, Communal heating, Energy centre
- Heat Network Efficiency SchemeHNES
- Government grants to improve the performance of existing heat networks, for example with better controls, insulation or heat interface units. Abbreviated HNES.See also: Green Heat Network Fund. Source: Heat Network Efficiency Scheme overview (GOV.UK)
- Heat Network Technical Assurance SchemeHNTAS
- A planned scheme setting minimum technical standards for heat networks, checked at stages from design to operation. Launch is planned for 2027.See also: Code Manager. Source: Heat Network Technical Assurance Scheme (GOV.UK)
- Heat network zone
- An area in England where government has decided a heat network is the lowest-cost way to provide low-carbon heat. Once the zoning regulations are in force and a zone is designated, certain buildings inside it can be required to connect.See also: Designation, Heat network zoning, Zone delivery area. Source: Energy Act 2023, Part 8, Chapter 2 (legislation.gov.uk)
- Heat network zoning
- The policy of identifying and designating heat network zones in England, created by the Energy Act 2023. It aims to give investors enough certainty about demand to build large networks.See also: Heat network zone, Energy Act 2023. Source: Energy Act 2023, Part 8, Chapter 2 (legislation.gov.uk)
- Heat network zoning pilot
- The programme in which the government worked with 28 local authority partners to test how zones would be identified, producing a zone opportunity report for each place. It is separate from the Advanced Zoning Programme.See also: Zone opportunity report, Advanced Zoning Programme. Source: Heat networks zoning pilot (GOV.UK)
- Heat Networks (Scotland) Act 2021
- Scotland's own heat network law, which lets councils or Scottish Ministers designate heat network zones and sets statutory targets for heat supplied by networks.See also: Local Heat and Energy Efficiency Strategy. Source: Heat Networks (Scotland) Act 2021 (legislation.gov.uk)
- Heat Networks Delivery UnitHNDU
- A government team that gives councils grants and technical help for early-stage heat network studies, and now helps identify future zones. Abbreviated HNDU.See also: Green Heat Network Fund. Source: Heat Networks Delivery Unit (GOV.UK)
- Heat Networks Investment ProjectHNIP
- An earlier government capital programme of £320m for heat networks, now closed and succeeded by the Green Heat Network Fund. Abbreviated HNIP.See also: Green Heat Network Fund. Source: Heat Networks Investment Project (GOV.UK)
- Heat pump
- A machine that uses electricity to move heat from a cooler source, such as air, ground, rivers or sewers, to a warmer one. Large heat pumps are a common source for new networks.See also: Water-source heat pump, Low-carbon heat
- Heat Supply Act (Denmark)
- Denmark's 1979 law requiring municipalities to plan heat supply, allocating areas to district heating or gas. It is often cited as the model for zoning.See also: Heat network zoning. Source: Regulation and planning of district heating in Denmark (Danish Energy Agency)
L
- Laid before Parliament
- The formal step of presenting a draft or made statutory instrument to Parliament. Some instruments must then be approved by both Houses before they can be made.See also: Statutory instrument
- Local Area Energy PlanLAEP
- A council-level plan for an area's energy system. In Wales these plans are expected to identify where zoning-style approaches could work.See also: Local Heat and Energy Efficiency Strategy. Source: Heat Strategy for Wales: action plan (Welsh Government)
- Local Heat and Energy Efficiency StrategyLHEES
- A strategy every Scottish council had to publish by the end of 2023, setting out how buildings in its area will decarbonise heat and where heat networks may fit. Abbreviated LHEES.See also: Heat Networks (Scotland) Act 2021. Source: LHEES guidance (Scottish Government)
- Low-carbon heat
- Heat produced with little or no fossil fuel, for example from heat pumps, recovered waste heat or geothermal sources. Zoning is designed to bring low-carbon heat networks to the places where they are cheapest.See also: Heat pump, Waste heat
M
- Market framework regulations
- The Heat Networks (Market Framework) (Great Britain) Regulations 2025, which made Ofgem the regulator and set up consumer protection for heat network customers.See also: Ofgem, Authorisation. Source: Heat Networks (Market Framework) (Great Britain) Regulations 2025 (legislation.gov.uk)
- Megawatt-hourMWh
- A unit of energy equal to 1,000 kilowatt-hours. Heat demand for buildings is usually measured in megawatt-hours a year, and the threshold for large non-domestic buildings in zoning policy is expressed in this unit.See also: Terawatt-hour, Heat demand
- Metering and billing regulations
- The Heat Network (Metering and Billing) Regulations 2014, which set rules on meters and bills for heat network customers. Several requirements were removed from 27 January 2026.See also: Heat meter, Heat cost allocator. Source: SI 2026/7 (legislation.gov.uk)
O
- Ofgem
- The energy regulator for Great Britain. It has regulated heat networks since 27 January 2026, under rules separate from zoning.See also: Authorisation, Market framework regulations. Source: Heat Networks (Market Framework) (Great Britain) Regulations 2025 (legislation.gov.uk)
R
- Registration
- The process by which existing heat networks must record themselves with Ofgem, by 26 January 2027.See also: Authorisation, Ofgem. Source: Who should register a heat network with Ofgem (Ofgem)
- Required building
- A building in a designated zone that falls into a category the regulations require to connect: new buildings granted planning permission after designation, existing communally heated buildings, and large existing non-domestic buildings with wet heating.See also: Communal heating, Wet heating system, Exemption. Source: Proposals for heat network zoning: government response (GOV.UK, Jan 2026)
S
- Standstill period
- A short pause after a public contract award is announced and before the contract is signed, during which losing bidders can challenge the decision.See also: Development partner
- Statutory instrumentSI
- A piece of secondary legislation made by a minister under powers in an Act. The zoning regulations will be a statutory instrument made under the Energy Act 2023.See also: Laid before Parliament, Zoning regulations
T
- Temporary exemption
- A deferral of the requirement to connect, lasting up to two years from the end of the connection window. It must be sought during the agreement period.See also: Exemption, Agreement period. Source: Proposals for heat network zoning: government response (GOV.UK, Jan 2026)
- Terawatt-hourTWh
- A unit of energy equal to one million megawatt-hours, used for national totals. Government's 2035 ambition for heat networks in England is expressed in terawatt-hours.See also: Megawatt-hour
W
- Warm Homes Agency
- A new public body created under the Warm Homes Plan. The Heat Network Zoning Authority is due to move into it once it is established.See also: Heat Network Zoning Authority, Warm Homes Plan. Source: Warm Homes Plan (GOV.UK)
- Warm Homes Plan
- The government's plan for home energy, published in January 2026. It commits about £1.1bn to heat networks over five years and to introducing zoning.See also: Warm Homes Agency, Green Heat Network Fund. Source: Warm Homes Plan (GOV.UK)
- Waste heat
- Heat produced as a by-product of another process, such as a data centre, factory, power station or the London Underground, that would otherwise be lost. Recovering it is a key opportunity for heat networks.See also: Energy from waste, Low-carbon heat
- Water-source heat pump
- A heat pump that draws heat from a river, the sea, a lake, a mine or a sewer. Several planned networks, including in central London, propose using them.See also: Heat pump
- Wet heating system
- A heating system that circulates hot water through radiators or underfloor pipes, such as a gas boiler system. Buildings heated only by direct electric heaters do not have one.See also: Required building
Z
- Zone coordination bodyZCB
- The local body, usually a council or combined authority, that will run a designated zone day to day: issuing connection notices, handling local exemptions and enforcing requirements. Not yet formally established anywhere.See also: Heat Network Zoning Authority, Connection notice. Source: Proposals for heat network zoning: government response (GOV.UK, Jan 2026)
- Zone delivery area
- The part of a designated zone in which a particular zone developer holds exclusive rights to build the heat network.See also: Zone developer, Heat network zone. Source: Proposals for heat network zoning: government response (GOV.UK, Jan 2026)
- Zone developer
- The company appointed through competition to design, build and run the heat network in a designated zone, with exclusive rights to do so in its delivery area. No statutory zone developer has yet been appointed.See also: Development partner, Zone delivery area. Source: Proposals for heat network zoning: government response (GOV.UK, Jan 2026)
- Zone opportunity report
- A study published by the Department for Energy Security and Net Zero for each of the 28 pilot places, mapping candidate zones, heat sources and likely costs. Publication of a report does not mean a zone exists.See also: Heat network zoning pilot, Candidate zone. Source: Heat network zone opportunity reports (GOV.UK)
- Zoning regulations
- The secondary legislation that will make heat network zoning work in practice, setting out designation, which buildings must connect, exemptions and penalties. Not yet laid before Parliament at our last check.See also: Statutory instrument, Energy Act 2023, Laid before Parliament