Sources of heat

Heat Trust's customer protection standards for heat networks do not specify fuel source, so any heat network no matter the fuel type can register with us. To find out more about registering with Heat Trust please see our supplier pages, or for more information for customers please see here

Heat networks can source their heat from any fuel or generation process; this is sometimes known as being fuel agnostic.
Typical examples of heat sources for heat networks are: gas boilers, Combined Heat and Power (CHP) plants, wasted heat (from industrial processes, wastewater treatment etc.) and biomass fuelled boilers. More heat networks are now being heated by technologies such as large-scale heat pumps (usually water or ground), geothermal sources or even underground transport. We have highlighted some examples of these in the UK below. There are also projects in development in the UK and operational internationally using waste heat from mine water, deep geothermal, data centresgreenhouses and large-scale solar thermal (often with seasonal thermal stores) to power heat networks.

Heat networks can also make use of thermal stores (large insulated tanks of hot water). These can either provide heating temporarily if the primary source of heat fails, therefore increasing the reliability of supply for customers; or they can supply heat at a time of high demand on the fuel source to help balance out demand. The time these can supply heat for depends on the size of the store, ranging from a few hours with small tanks to between seasons with large ground pits.


Currently most heat networks (90%) use gas as their primary fuel source, typically through one or more gas-fired boilers. The gas is usually sourced from the national gas grid, and of the UK’s total gas demand in 2018, about 50% came from the UK’s contintental shelf and 50% was imported. However 'biogas' from anaerobic digesters, e.g. at sewage treatment works, can also provide the gas fuel for heat networks.

Some gas boilers produce only heat, like individual property boilers, however some produce electricity  (burning the gas to create steam which turns turbines) and capture the excess heat at the same time. This is known as a Combined Heat and Power (CHP) plant (which can also use fuels other than gas) and is often more efficient than generating electricity or heat independently of each other.

Name  Bicester Heat Network
Fuel Source  Gas CHP
Location  Elmsbrook, Oxfordshire
Size  800KWe CHP engine, 80m3 thermal store and back up gas boilers
Types of end users 393 zero carbon homes, a primary school, local shop, eco pub and community centre
Interesting facts Part of the UK’s first Eco-town, aiming to be zero carbon
Links to find out more


Name  Bristol Paintworks 
Fuel Source  Gas boilers
Location  Bristol
Size  8 x 250 kWe modular gas boilers
Types of end users  221 residential apartments and town houses, studios, offices, a café bar and exhibition venue
Interesting facts  It is a redeveloped paint and varnish factory
Links to find out more


Wasted heat

Many industrial processes generate heat as a by-product, such as incinerators, underground transport and sewage treatment works. Heat networks can make use of otherwise wasted heat by transporting it to an end user that requires heat. This is often limited by the end-users of heat not being close enough to the source of wasted heat.

Energy From Waste (incinerator)

Name SELCHP (South East London Combined Heat and Power)
Fuel Source
Waste heat from incinerator (combusts waste from households to create electricity)
Location Southwark, London
Size 5km heating network for heat and hot water
2,500 Southwark properties
Types of end users   Residential
Interesting facts            It came from a consortium of three London Boroughs trying to tackle environmental problems and issues of landfill space, using waste that cannot be recycled for electricity generation
Links to find out more         


Waste from transport

The London Underground produces waste heat, mostly from friction of the trains on the rails. Through adding a heat pump, the temperature of the heat captured can be raised to provide heating to a heat network.

Name Bunhill Heat Network
Fuel Source         Waste heat from London Underground (Northern Line)
Location Ventilation shaft of Northern Line of London Underground, Central Street
Size 1MW heat pump to heat an additional further 1,000 homes
Existing: 2MW CHP with large thermal store
Types of end users  Existing: 800 homes in Bunhill ward, as well as Finsbury Leisure Centre, Ironmonger Row Baths and offices on Old Street
Interesting facts Phase 1 has been in operation with a CHP since 2012. Phase 2 is to connect to the Underground in 2019.
During the summer months, the system will be reversed to inject cool air into the tube tunnels.
Links to find out more


Waste heat from sewage treatment works

Some of the processes used to treat wastewater, including sewage, involve anaerobic digestion of organic matter within the waste water, which generates heat as well as producing gas.

Name Stirling heat network
Fuel Source    Waste heat from wastewater treatment works and biogas CHP from the anaerobic digesters on site
Location Stirling, Scotland
Types of end users                               Key public buildings, including The Peak Leisure Centre, Forthbank Stadium, St Modan’s High School, numerous commercial offices and new build homes
Interesting facts

First CHP in UK to be used with heat from waste water pump system to deliver heat for a heat network.
It is expected to save around 381 tonnes of carbon a year.

Links to find out more



Biomass usually comes in the form of wood pellets burned in a furnace. These wood pellets can come from waste/off-cuts from the wood industry or virgin woodland.

Name Queen Elizabeth Olympic Park
Fuel Source Woodchip fueled biomass boiler for heat generation and a combined cooling, heat and power (CCHP) plant using natural gas
Location London, converted Olympic Park (2012 games)
Size Initial capacity of 46.5 MW of heating and 16 MW of cooling in two energy centres
16km heating network and 2km cooling network
Types of end users                 Olympic Park, the Westfield shopping centre, residents of East Village and the neighbouring area
Interesting facts

It is the largest decentralised energy scheme in the UK
It heated the Olympic Park and Village during the 2012 Olympic and Paralympic Games

Links to find out more


Heat pumps

Heat pumps capture heat energy from either ground, water or air, and then through a pump powered by electricity increase the temperature to heat homes and buildings. This increase or ‘upgrade’ in temperature works in a similar way to how a fridge is cooled but in reverse. Heat is generated through rapidly increasing the pressure of refridgerant gasses in a contained space, this increases the temperature of the gases, which can pass to adjacent water or air, piped onwards. At the scale of heat networks, only water or ground source heat pumps tend to be used.

Water Source

Name Queen’s Quay
Fuel Source 2 x 2.6 MW water source heat pumps, from the River Clyde
Location                  Clydebank, Glasgow
Size 2.5km of heating network
Types of end users       Local homes, businesses and public buildings such as West Scotland College and Clydebank Library and over 1,000 new homes
Interesting facts          First heat network powered by a river-source heat pump in Scotland
Links to find out more


Ground Source

Name Enfield Council: Ground Loop Array Heat Pump
Fuel Source Ground source heat pump
Location Enfield, London
Size 4km heating network
Types of end users 402 flats in 8 tower blocks
Interesting facts

100 boreholes capture the heat at depths between 197 – 227m
It replaced electric heating which was expensive

Links to find out more



In the UK the top 10 - 15m of ground is heated by the sun and acts as a thermal store. By running pipes of water through the ground at these depths, the heat will be transferred to the water, which can then go on to heat people's homes. In some places, such as Iceland, the heat from volcanic activity (and heat conducted upwards from the Earth’s core and mantle) can be captured, which have much higher temperatures.

Geothermal is different to ground source heat pumps because electric pumps aren't used to raise the temperatures, and their pipes tend to go deeper into the ground.

Name            Southampton District Energy Scheme (SDES)
Fuel Source  Large-scale CHP plant, supplemented by geothermal energy and conventional boilers; also provides cooling
Location        Southampton
Size Over 40 GWh of heat p.a
Types of end users TV studios, a hospital, a university, a shopping centre, a civic centre, residential buildings and a hotel – as well as public and private-sector residential developments.
Interesting facts Currently saving around 10,000 tonnes of CO2 emissions p.a.
Links to find out more


If you know of an operational heat network in the UK heated by an innovative low carbon fuel source then please let us know via our contact page.

Heat Network related documents

Below is a list of some of the key reports about heat networks which you may have heard mentioned. It is not exhaustive, but might prove a good starting point if you want to learn more about the heat network market and the governments’ positions on heat networks.

They are ordered by release date, with most recent first.

Heat Trust Reports

Heat Trust Annual Report 2020 - Heat Trust (August 2021)

This is our fifth annual report. It presents complaints and interruptions statistics as well as other data from both Registered Participants and the Energy Ombudsman from 2020. In addition it sets out the importance of Heat Trust in the current stage of statutory regulation development, and an overview of our latest activity.  We are pleased to see membership increase but continue to work towards supporting more of the heat network industry to offer minimum protection standards to their customers.

Heat Trust Annual Report 2019 - Heat Trust (May 2020)

This is our fourth annual report. It presents analysis of data from both Registered Participants and the Ombudsman from 2019, as well as our reflections on the first four years of Heat Trust and recommendations for developing regulation which draw on this experience. We are pleased to see that the voluntary standards set by Heat Trust are having a positive impact on the market and delivering improvements to customer experience.

Heat Trust Annual Report 2018 - Heat Trust (November 2019)

This is our third annual report. Heat Trust now provides protection to 10% of the market. Reflecting on the experience gained over three years, the report sets out the key principles to consider as regulation of the market is developed. The report also provides a summary of performance of heat networks registered with Heat Trust over the previous three years, including complaints from the Energy Ombudsman, interruptions and debt and disconnection.

Heat Trust Annual Report 2017 - Heat Trust (November 2018)

This is our second annual report. The report provides a summary of the performance of heat networks that are registered with Heat Trust, and an update on Heat Trust developments and activities. It also provides greater detail on interruptions and complaints data, and case studies from complaints that went to the Energy Ombudsman, the independent dispute resolution service.

Heat Trust First Annual Report 2016 - Heat Trust (October 2017)

This is the first annual report from Heat Trust. It summarises the performance of heat networks that are registered with Heat Trust, and draws out key findings from the first year of operation.


Other Reports

Spotlight on complaints about heating, hot water and energy in social housing - Housing Ombudsman (February 2021)
The Housing Ombudsman makes the final decision on disputes between residents and member landlords. Membership is compulsory for social landlords, primarily local authority landlords and housing associations, and some private landlords are voluntary members.The report focuses on complaints about heating and hot water – including heat networks and gas servicing. These are issues where maladministration is often found in complaints brought to the Housing Ombudsman. Complaints about heating and hot water systems are more common in the winter months and can have a serious impact on residents – particularly those who are older, or have disabilities or other vulnerabilities.

Bringing heat networks up to standard: How heat networks can start delivering better customer service outcomes - Citizens Advice (January 2021)
To find out what heat network suppliers still need to fix ahead of upcoming regulation, Citizens Advice analysed the information given to customers by 20 heat network suppliers. They reviewed the information on their websites and also mystery shopped their customer service phone lines. This report shows the results of these exercises.

CP1: Heat Networks: Code of Practice For The UK (2020) – CIBSE – Chartered Institution of Building Services Engineers (January 2021)
This second edition of the Code of Practice: Heat networks provides a very significant update to the 2015 version. The previous edition had been highly successful in establishing minimum standards to improve the quality of district heating projects from concept through to operation. A series of fully integrated checklists now presents a more structured and robust toolkit for checking compliance with the Code of Practice, among other updates.

Heat networks: building a market framework Consultation – BEIS - Department for Business, Energy and Industrial Strategy (February 2020)
In this consultation, BEIS sought views on policy options for regulating heat networks to protect consumers and ensure fair pricing, while supporting market growth and the development of low-carbon networks.

This consultation set out:

  • measures to increase levels of investment in the sector, such as provision of market information and support for strengthening local approaches that will help generate additional demand certainty on projects
  • policy options for establishing a market framework to deliver important consumer protections, equivalent to those offered to gas and electricity customers, as the market expands
  • proposals relating to the choice of regulator, the regulatory approach, enforcement powers and step-in arrangements
  • proposals for protecting consumers including on transparency, pricing and quality of service standards
  • proposals for developing technical standards and certification and accreditation processes to improve the quality, cost and reliability of heat networks
  • proposals for giving heat networks equivalent rights and powers (such as undertaker or statutory access rights) compared with other utilities
  • proposals to drive decarbonisation of heat networks and use of waste-heat sources

Pre-payment meters and heat networks: learning the lessons - Citizens Advice (July 2019)
This research explores the experiences of those on heat networks that also use prepayment meters. The report makes recommendations to improve the experiences of these consumers and help prevent people being disconnected from their heating and hot water.

Net Zero – The UK’s contribution to stopping global warming – CCC – Committee on Climate Change (May 2019)
This report reassesses the UK’s long-term emissions targets, i.e. how we can achieve ‘net zero’ by 2050. The conclusions are supported by detailed analysis published in the Net Zero Technical Report that has been carried out for each sector of the economy.
Heat networks are identified as part of the solution to decarbonise the UK’s heating sector, with 5 million homes anticipated to be on heat networks by 2050.

UK housing: Fit for the future? – CCC – Committee on Climate Change (February 2019)
This report assesses whether the UK’s housing stock is adequately prepared for the challenges of climate change; both in terms of reducing emissions from UK homes and ensuring homes are prepared for the impacts of climate change. This includes both retro-fitting the existing 29 million homes in the UK, and preparing new homes.
Heat networks are identified as part of the solution to decarbonise the UK’s heating sector; particularly as after 2025 no new homes should be connected to the gas grid.

Heat networks: developing a market framework – BEIS – Department for Business, Energy and Industrial Strategy (December 2018)
The government’s Clean Growth Strategy sets out a significant role for heat networks as a ‘low-regrets’ component of meeting our legally binding decarbonisation commitments. This requires a major increase in growth rates and investment in the UK heat network market, supported by effective consumer protection measures. This document sets out:
• the context of the government’s support for heat networks and the role of the sector in the decarbonisation of heat
• the government’s priorities for establishing a market framework to deliver this growth in a way that protects consumers and delivers sustained investment as well as maximising the potential economic and environmental benefits from heat networks
It is a response to the CMA’s heat networks market study, and the ADE’s Shared Warmth report.

Heat networks: the experiences of consumers and operators – BEIS – Department for Business, Energy and Industrial Strategy (December 2018)
This qualitative research contributes to a wider understanding of the experiences of heat network consumers and operators. This work supplements the Heat Networks Consumer Survey published in December 2017.

Heat networks market study – CMA – Competition and Markets Authority (July 2018)
The CMA carried out a market study into domestic heat networks, to review how well the market is working and if consumers are getting a good deal. The report sets out analysis of relevant issues in the market for communal and district heating schemes on:
• prices based on a representative sample of heat networks,
• the supply chain, heat network delivery models, the potential environmental and economic benefits of heat networks, government proposals for expanding the sector and international experiences of heat networks,
• a high level financial analysis of the sector,
• in-depth interviews to examine consumer awareness, understanding and expectations about heat networks before moving into a property,
• future options for regulating the sector,
• customer complaints and reviewed key customer documents.
Heat Trust supports the CMA’s call for the heat network industry to be regulated and welcomes its recommendation that the framework draws on Heat Trust’s experience. Heat Trust’s full comment can be found here.

Experimental statistics on heat networks – BEIS – Department for Business, Energy and Industrial Strategy (March 2018)
The Heat Network (Metering and Billing) Regulations 2014 require every heat network supplier/operator to submit a notification once operational and at four yearly intervals to provide information on the status and performance of network(s) managed. This paper sets out preliminary results of the data collected, including total number of heat networks in the UK, whether they are district or communal, if they provide heating/ hot water/ cooling or a combination, where they are located and their primary fuel source.

Consumer Expectations of Regulation: Heat Networks – Citizens Advice (March 2018)
This project conducted 8 focus groups in 4 different heat network locations across the UK to look at the experience of consumers on heat networks, the complaints process and the perceptions of consumer protection and introducing regulation.

Shared Warmth | A heat network market that benefits customers, investors, and the environment – The ADE – The Association for Decentralised Energy (January 2018)
This report is the culmination of wide ranging industry stakeholder collaboration. The Heat Network Task Force, led by the ADE, considered a range of options from industry action to regulatory intervention. It considered how to best address the investment risk associated with long-term infrastructure like heat networks. The report sets out a comprehensive set of principles that are needed to give heat network customers the same level of protection enjoyed by customers receiving heat by other means.
The report recommends the introduction of a regulatory framework that provides those looking to invest in heat networks with 'demand assurance' in return for meeting customer protection standards.
Heat Trust welcomed the report’s recommendations, for more details see here.

Market report: Heat Networks in the UK – The ADE – The Association for Decentralised Energy (January 2018)
This report highlights the opportunities offered by heat networks through developing a clearer picture of the market. Information contained in this report is based on a survey carried out between January and November 2017 of heat networks in Great Britain, which represented one-third of the overall number of customers connected to heat networks in the UK. Information was collected from a wide range of organisations, including public and private actors, and the information covered about 160,000 domestic and commercial customers on 810 different networks.
Heat Networks Consumer Survey: consumer experiences on heat networks and other heating systems – BEIS – Department for Business, Energy and Industrial Strategy (December 2017)
The Heat Networks Consumer Survey is a BEIS research project into the experiences of consumers on heat networks.
The survey was sent via post to consumers between April and July 2017 and received over 3,700 responses from heat network consumers and nearly 1,800 responses from consumers not on heat networks to act as a comparison. The report sets out the findings from the survey and covers a range of topics, including satisfaction with system performance, price and transparency of billing, and consumer service.
Heat Trust welcomed the survey results which found that heat networks registered with Heat Trust are providing better billing and customer service standards for consumers. For Heat Trust’s full response see here.
Next steps for UK Heat Policy – CCC – Committee on Climate Change (October 2016)
Heating and hot water for UK buildings make up 40% of our energy consumption and 20% of our greenhouse gas emissions. It will be necessary to largely eliminate these emissions by around 2050 to meet the targets in the Climate Change Act and to maintain the UK contribution to international action under the Paris Agreement.
Progress to date has stalled. The CCC says that the Government needs a credible new strategy and a much stronger policy framework for decarbonisation of buildings over the next three decades. Many of the changes that will reduce emissions will also contribute toward modern, affordable, comfortable homes and workplaces and can be delivered alongside a major expansion in the number of homes. This report considers that challenge and sets out possible steps to meet it.
Research on district heating and local approaches to heat decarbonisation – CCC – Committee on Climate Change (November 2015)
This report is research supporting the CCC’s report on the UK’s Fifth Carbon Budget advice (the latest update on the UK’s legal commitments on reducing emissions). There are three core scenarios for deployment of district heating to 2050. The three scenarios reflect different levels of policy intervention to incentivise and assist the roll-out of district heating in the UK. It also presents possible future heat network coverage if certain policies and measures are put in place, such as providing 10% of UK’s heat demand by 2030 and 18% by 2050 (up from 2% now).


Existing Legislation

The Heat Network (Metering and Billing) Regulations 2014 with a few amendments made in the Heat Network (Metering and Billing) (Amendment) Regulations 2015, was made UK law from the requirements regarding the supply of distributed heat, cooling and hot water as part of the EU Energy Efficiency Directive requirements.

Key requirements include:

  • heat suppliers have a duty to notify their network to the Government
  • meters must be installed to measure consumption of heating/ cooling/ hot water, where cost effective and technically feasible, and install a heat cost allocator where not
  • sending a bill at least once a year, based on actual consumption where possible, and containing clear explanations of how the bill was calculated, amongst other billing information


Government Support

UK Government

The government has produced guidance for suppliers on how to follow these regulations. More general information about heat networks can be found on the Government website pages here:, including their support provided for heat networks through two key mechanisms: HNDU and HNIP.

The Heat Networks Delivery Unit (HNDU) was established in 2013 to address the capacity and capability challenges which local authorities identified as barriers to heat network deployment in the UK. The Unit provides funding and specialist guidance to local authorities who are developing heat network projects.

The Heat Networks Investment Project (HNIP) is delivering £320 million of capital investment support to increase the volume of heat networks built, deliver carbon savings for carbon budgets, and help create the conditions for a sustainable market that can operate without direct Government subsidy. The pilot phase of the Heat Networks Investment Project ran for 6 months and awarded £24 million to 9 successful Local Authority projects in March 2017.

The Green Heat Networks Fund (GHNF) is due to replace HNIP and was consulted on in early 2021. It is a capital grant funding programme which is intended to help new and existing heat networks to move to low and zero carbon technologies. Its objectives are to: achieve carbon savings and decreases in carbon intensity of heat supplied, increase the total amount of low-carbon heat utilisation in heat networks (both retrofitted and new heat networks) and help prepare the market for future low-carbon regulation and ensure compliance with existing regulations (such as the Heat Network (Metering and Billing) Regulations, Heat Network Market Framework and the Future Homes Standard).

Scottish Government

The Scottish Government have lots of information about heat networks and their context in Scotland on their website here, including links to their Heat Map.

There is also a dedicated website for district heating set up by The Heat Network Partnership, which aims to boost the uptake of low carbon heat technologies in Scotland and focuses the efforts of a number of agencies working in this area.

The Heat Networks (Scotland) Bill, setting out regulation of heat networks in Scotland, has now been passed. For more details see our Regulation update page.

Further information will be added soon.

What is a heat network?

A heat network is the system of insulated pipes which transports heat from a source (or multiple sources) to more than one end user. The UK government has stated that heat networks will be used more frequently to heat our homes and businesses. In short, heat networks form part of new energy infrastruture, vital in supporting the move to a low carbon energy system.

ch network infographic

They are natural monopolies which means that one organisation is the supplier for all properties on a single heat network.

There are two types of heat networks: district heating and communal heating.

  • Communal heat network:Communal heating is the supply of heat and hot water, from a source usually known as the energy centre, to a number of customers within one building only. The energy centre often consists of a large boiler in the basement of a building with the heat and hot water distributed through the building via a series of pipes.


dh network infographic

  • District heat network: District heating involves a local energy centre that supplies heat and hot water to customers in more than one building. District heating networks can range in size from a few hundred metres supplying just a few homes to several kilometres of pipe supplying heat and hot water to multiple buildings in a development.


According to market data collected by government, most heat networks are actually communal heat networks (85%).

Some new heat networks are built for large projects which are completed in stages. This might mean that some residents will move in to their homes before others are built, which will be joined to the heat network when completed.

Who would be a heat network supplier?

Heat Trust defines the heat network supplier as the organisation that is contracted to provide heating and/ or hot water to each property – they would provide the Heat Supply Agreement (or customer charter) to each occupant on the heat network.

The type of organisations that fulfils this role can vary network to network. For example, this could be a:

  • A dedicated heat network company (ESCO),
  • The property developer,
  • A housing association,
  • A local authority,
  • A community organisation,
  • A management company,
  • A company set-up by the freeholder to operate the network

All heat network suppliers that have registered one or more heat networks with Heat Trust can be found here.

Heat Interface Units (HIUs)

Some heat networks will include a heat interface unit within each property.

A heat interface unit (HIU) is the bridge between the communal or development-wide heat network and the individual property. It is a unit that brings hot water to and from the main heat network into each property.

There are two main types of HIU.

  1. Heat-only HIUs – these are used on heat networks that only provide space heating to properties connected to the heat networks. The hot water is typically provdided by an electric immersion heater and hot water tank.
  2. Heat and hot water HIU – these are used on heat networks that provide both space heating and hot water to each property connected to the heat network.

There is now an industry standard for the performance of HIUs. More information can be found on the BESA website here:

Where are heat networks in the UK?

The database of registered heat networks in the UK[1], recorded that in 2015 there were just under 14,000 heat networks. Of these around 2,000 were district heating and 12,000 were communal[2]. These serve nearly 480,000 customers, providing around 2% of the UK buildings heat demand[3].

Heat networks require a certain density of heat demand in order to be economic. The geographical distribution therefore reflects that heat networks, and particularly district heating networks, are located in urban areas, new build developments and some rural areas.

BEIS HN distribution map

BEIS map of heat network distribution in the UK by local authority.

Nearly 12,000 of all heat networks in the UK are in England (86%). 6% are in Scotland, 2% in Wales and 0.6% in Northern Ireland.

29% of heat networks were in London, and a further 14% in the South-East of England. Others are concentrated around Manchester, Birmingham, Newcastle, Sheffield, Bristol and Glasgow. Belfast has the highest proportion of heat networks compared to other regions in Northern Ireland.

Over 75,000 buildings are connected to heat networks. 80% of heat networks are connected to residential buildings. An even higher proportion of final customers are residential (92%)[4]. This reflects the higher proportion of communal heating networks, which are generally apartment blocks. 9% of heat networks are connected to education buildings, and 7% are commercial.

The majority of heat networks supply both space heating and hot water (70%), with only 8% supplying cooling as well.

Only 28% of final customers have meters. Scotland had the highest proportion of final customers with meters, at 40%, and Wales had the lowest (4%).

Of those who responded to the question (12,000), 32% billed their customers annually, 25% monthly, 16% quarterly and 27% responded with ‘other’, which could include Pay As You Go (PAYG).

Currently most networks (90%) used gas as their primary fuel source. The next most widely used fuel source was electricity (5%) followed by bioenergy and waste (2%). See our sources of fuel page for more information and some examples.

To find out which heat networks are registered with Heat Trust, click here





Heat networks and climate change

In the UK approximately 40% of our energy consumption and 20% of our greenhouse gas emissions are due to the heating and hot water supply for our buildings.

Emissions from heating UK

Infographic from the CCC's Next Steps for UK Heat Policy Report, see below.

The UK government has legislated that we must recude greenhouse gas emissions to net zero by 2050. This provides the legal imperative to decarbonise the heat sector, which means that the UK will need to eliminate almost all emissions currently produced by heating and hot water consumption.

Heat networks are a part of our pathway to decarbonising heat, through efficiency of supply and the fuel source.

Economies of scale

It can be more economic to have one large heat generator and pipe the heat to many properties, than for each property to have its own generator, especially where there is a large capital cost associated with the heat generator (eg ground arrays for heat pumps). They are most efficient in heat dense areas, where pipes can be shorter between properties.

Fuel source

Heat networks are fuel agnostic, and so can be heated by any fuel. This includes low carbon heat generation from the beginning, or switch to an alternative source of heating at a later stage. See here for some examples of renewable sources of heat for heat networks in the UK already, from otherwise wasted heat to geothermal.

Additionally, thermal stores are increasingly used to balance demand swings and maintain supply during short outages. These are typically large insulated tanks of water that can store excess heat from generation at periods of low demand and supply heat at periods of high demand.

Historywhy heat nets block

Heat networks have been widely used in Denmark since the 1970s, and are an established technology. However in the UK heat networks only supply 2% of current heat demand, having developed the gas grid to fuel boilers in individual dwellings as the main heating source since the 1970s. Please see our timeline of how the history of heating in the UK has developed.

Even so, around 13% of households in the UK are still not connected to the gas grid, where heating is supplied largely by oil heaters and sometimes electricity, or heat networks.


Future of heat networks

Scientific recommendations

The Committee on Climate Change (CCC) is the independent advisory body to the UK government on targets and progress made in reducing greenhouse gas emissions and preparing for climate change. The Committee identified what it calls low-regret routes to reducing emissions from heating buildings that the Government should pursue immediately which included “the roll-out of low-carbon heat networks in population-dense urban areas, along with energy efficiency and other measures”.

In its latest advice to the UK Government on the UK’s ‘carbon budgets’, the Committee recommended growth in heat networks, with up to 18% of heat demand met by heat networks by 2050 (see table below) from a current baseline of about 2%.

         Text Year Text     Fraction of UK heat demand served by heat networks Number of homes connected to heat networks
0.5 million
1.5 million
5 million

Their recommendations also included a major programme to build and extend low-carbon heat networks in heat-dense areas, connecting 1.5 million homes by 2030 and reaching 5 million homes by 2050.

This encompasses both retrofitting existing homes (there are about 29 million homes currently in the UK) as well as connecting new homes. This comes in conjunction with advice that after 2025, no new homes should be connected to the gas grid, and that new homes should have low-carbon heating systems instead.

The CCC also emphasised the expansion of non-domestic connections to heat networks, which in their ‘central’ scenario would account for 53% of total heat delivered by heat networks by 2050 (although only 28% of UK heat demand is non-domestic). Non-domestic buildings are largely concentrated in urban areas with a higher heat density, where heat networks are more likely to be deployed.

Government support

As part of their commitments to reducing their carbon emissions, the UK and Scottish governments are supporting the development of heat networks, through investment incentives and developing regulation which will support the sector.

The UK government department for Business, Energy and Industrial Strategy (BEIS) set out the context of the government’s support for heat networks and the role of the sector in the decarbonisation of heat in a report in December 2018. This responded to the CMA’s market study and the ADE’s Shared Warmth report on the heat network market.

Government acknowledged in the Clean Growth Strategy that they have set out a significant role for heat networks as a ‘low regregts’ component of meeting their decarbonisation commitments. They recognised that for the last 50 years we have largely relied on gas to heat our buildings, and heat networks are a key technology which can facilitate the transition away from fossil fuels towards low carbon energy sources.

See or our existing legislation section for more information on how the UK and Scottish governments are supporting heat networks. Also see our reports section for further reading on the development of the heat network market in the UK.

If you’re thinking of moving in to a home or building heated by a heat network - these are our top questions to ask before you decide:

  • Is the heat network registered with Heat Trust? If not, are there plans to? (this will ensure you are provided with minimum customers standards that are comparable to the rest of the energy market and your supplier is audited.)
  • What support do you provide for customers in vulnerable situations? (This can be specific for a situtation you already know about, or in general as any of us may find ourselves in unexpected situations at any time.) 


Heat Trust New Icons 01Bills 

  • How do you calculate bills? (this is a potential source of confusion for customers who are used to other types of heating e.g. gas boilers or electric heaters)
  • What tariff will I be placed on? What other tariffs are available to me, and how will you let me know if I’m on the best one for me? (Some suppliers may offer multiple tariffs, some might only offer one)
  • How can I pay my bills? And how often? (Heat network suppliers may offer different ways to pay, such direct debit, standing order or pay as you go, you may be able to pay at a local store or over the telephone to set up a regular payment)
  • What happens if I can’t pay my bill? (suppliers should be able to talk this through with you and either point you in the direction of some independent debt advice, and/or set up a repayment plan which should make paying your bills more manageable) 


Heat Trust New Icons 03Meters 

  • Is there a meter for my property? (All new build properties are required by law to have an indiviual meter for each property. For older properties there may only be a meter for the building, not for each individual property)
  • Do I need to submit meter readings? (some meters do this automatically, others require the customer to send in meter readings to their supplier at regular intervals; this may be via telephone or online, or another method)
  • Will I have a smart meter? (this may show you more detailed information about your consumption patterns)


Heat Trust New Icons 02Contact

  • If something goes wrong...What are your emergency/ outage response times? Do you provide compensation if these last for a certain period of time, and what is the level of compensation? (in case something goes wrong, it is useful to know how quickly you can expect it to be fixed)
  • How can I contact you? For emergencies, outages, enquiries or complaints? (this could be telephone, email, text, online webchat etc.)
  • Do you hold drop-in sessions for customers or developers? (this can be in many forms but offers an opportunity for face-to-face questions and answers)
  • What do I need to do when I move in to set up my account with you? Or when I leave? (this could include providing your details and date of moving, as well as meter readings)
  • What is your complaints policy? (All customers should be provided with information on how they can raise a complaint, how the complaint will be managed and what independent redress is in place, if the supplier can not offer a satisfactory resolution.


Download our factsheet for a summary of our key standards.