Heat networks and district heating

Communal heat, district heat, HIUs and heat-pump network designs.

A heat network uses shared infrastructure to provide heating, cooling or hot water to more than one property. A communal network serves multiple occupiers within one building or site. A district network connects more than one building and may extend across a neighbourhood.

The network operator controls and maintains the physical assets. The heat supplier provides heat to customers and is normally their main commercial contact. They may be the same organisation, a landlord or separate companies. A gas or electricity company supplying fuel to the energy centre is not necessarily the heat supplier.

Not every network distributes hot water at the same temperature

In a conventional network, an energy centre heats water and pumps it through insulated mains. A building substation or heat interface unit transfers heat into the customer’s heating and hot-water system. Sources can include boilers, combined heat and power, large heat pumps, recovered waste heat, geothermal heat or a mixture.

In a shared ground loop or ambient network, the common pipe carries low-temperature source fluid and each property has its own heat pump. The resident may buy electricity for that heat pump while paying a separate loop charge. This is still a heat network for current Great Britain regulation, but its metering and costs differ from buying finished heat from a hot network.

The physical architecture should be established before comparing tariffs or efficiency. “District heating” is not enough description.

Heat interface units

An HIU is the boundary between a conventional network and a dwelling. An indirect HIU uses heat exchangers to separate network water from the dwelling’s heating and hot-water circuits. A direct arrangement may connect network water to part of the internal system. The right arrangement depends on pressure, water quality, ownership and building design.

HIU performance affects the whole network. Poor control, fouled strainers, oversized bypasses or a high return temperature can increase pumping and generation losses for everyone. Domestic hot-water output depends on incoming network temperature and flow, mains-water conditions and the selected unit. A headline kW rating does not prove satisfactory tap performance.

Residents need to know which side of the HIU they must maintain and who attends a fault. A cold radiator can arise in the dwelling circuit, the HIU, the building network or the energy centre, so clear boundaries matter.

Heat pumps in heat networks

Large heat pumps can feed a central hot-water network from air, water, ground or recovered heat. Their efficiency depends strongly on source and network temperatures. Lower return temperatures can improve heat-pump and distribution performance, while an old network designed for high temperatures may require building and HIU upgrades before temperatures can be reduced.

An ambient loop moves the temperature lift into each building. This can reduce standing heat loss and allow heat to be exchanged between buildings, but it adds individual compressors and depends on a well-controlled common source circuit.

Neither design is automatically low carbon. Electricity use, backup or peak boilers, pump energy, distribution loss and refrigerant leakage all belong in the assessment.

What appears on the bill

A bill may include a unit charge for measured heat, a standing charge, maintenance or asset charges, and other contractually defined costs. Some landlords recover elements through a service charge. On a shared ground loop, the largest heating energy cost may instead appear on the resident’s electricity bill.

Heat-network customers often cannot switch the physical network supplier because only one set of pipes reaches the property. That makes the tariff formula, cost allocation, contract term and complaints route especially important. Ofgem’s fair-pricing framework is not the domestic gas and electricity price cap, and a connection should not be described as price-capped unless a specific rule or contract supports that claim.

Recent bills for a comparable dwelling need occupancy and heat-use context before they can inform a forecast. The current tariff, standing charges, indexation, planned capital works and any arrears or sinking-fund treatment complete the cost position.

Current regulation in Great Britain

As at 22 July 2026, Ofgem regulates heat networks in England, Scotland and Wales. Operating networks received deemed authorisation when the regime began, and operators and suppliers must follow the authorisation conditions relevant to them and register through Ofgem’s process.

The consumer-protection rules cover standards of conduct, service quality, billing and transparency, back-billing, contracts, vulnerable consumers and security of supply. Heat-network consumers can use Citizens Advice or Consumer Scotland for support and the Energy Ombudsman for eligible unresolved disputes.

Shared ground loops are in scope but have fewer obligations in some circumstances. Self-supply and industrial networks can also have different obligations. The current Ofgem scope guidance should be used to identify the operator, supplier and rules for a particular network.

Northern Ireland is outside Ofgem’s Great Britain heat-network regime and retains separate arrangements.

Metering and technical standards

Metering obligations depend on the network and current rules. Where heat is billed from a meter, the meter, data and bill calculation need to be accurate and maintained. A meter does not by itself prove fair cost allocation: the standing charge and division of communal losses still matter.

As at 22 July 2026, the government is developing regulatory technical requirements and the Heat Network Technical Assurance Scheme. Draft specifications and assurance material exist, but the staged technical regime should not be described as if every existing network is already certified to it. Operators should use the live government and Ofgem pages for implementation status.

Good practice already requires design and commissioning evidence: source efficiency, pipe heat loss, return temperatures, pumping energy, water quality, metering, controls and an operating strategy. Regulation is a floor, not a substitute for that evidence.

Tariff, contract and service information

The available information should identify:

the operator and supplier, with current Ofgem details
the heat source and backup plant
whether the dwelling buys heat, electricity for its own heat pump or both
metered, fixed, indexed and service-charge costs
ownership and maintenance of the HIU or in-home heat pump
fault response, outage support and complaints routes
published efficiency, network-loss and return-temperature data
planned plant, pipe or decarbonisation work and its funding

A network can use efficient low-carbon heat and remove individual combustion appliances from homes. It can also lock residents into poorly explained charges or ageing communal assets. The contract, operating data and regulatory identity are as important as the technology in the energy centre.

Applies to

Heat

Last reviewed

22 Jul 2026