Last Mile delivers first phase of the UK’s largest low-carbon water-source heat network at Welborne Garden Village
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- Last Mile, with design and build partner Rendesco, deliver first ambient heat network of its kind to utilise water from an operational reservoir owned by Portsmouth Water
- The first of 700 homes, commercial properties and community buildings are already receiving low-carbon heat, cooling and hot water
- 80% lower emissions than traditional gas heating
WELBORNE, UK, 05 June 2025: The Last Mile group of multi-utility infrastructure companies is delivering a water-source ambient heat network at the mixed-use Welborne Garden Village development in Hampshire, England.
The first phase of the multi-phase project, delivered by Buckland Development, will see up to 700 homes, a primary school and a village centre comprising shops, pubs and cafes connected to Last Mile’s new ambient heat network. This network is expected to save residents an average of £160 per year for a typical three-bedroom house, compared to an air source heat pump alternative [1].
The heat network uses a unique, first-of-its-kind technology in the UK. It draws stable temperature water from Portsmouth Water’s nearby underground Hoads Hill Reservoir and feeds it to an energy centre where a heat exchanger transfers energy from the water into an ambient heat network. Individual heat pumps at each property then convert that energy into space heating and hot water. The heat network serving the properties is a closed loop system, separate from the water network that circulates water from the reservoir to the energy centre. This ensures there is no risk to drinking water quality or supply.
It can also use the reservoir as a heat sink for cooling in warmer months and facilitates building-to-building heat transfer, transforming excess heat produced by cooling in one building into heat and hot water for other buildings. This makes it significantly more efficient than alternative heat solutions, resulting in 54% lower CO2 emissions than systems using air-source heat pumps and 80% less than gas boilers.
As Welborne’s master developer, Buckland has assembled a consortium committed to innovative technologies that encourage low carbon living in connected and energy efficient homes, integrated with extensive publicly accessible green spaces.
The Future Homes Standard is anticipated to require developers to reduce emissions for new homes by 75-80% compared to current standards. While many are focused on meeting this goal, few are comfortable with managing utilities once their developments are completed as this is not their traditional business model. Last Mile Heat is a joint venture between Last Mile and the heat network’s design and build partner Rendesco. Last Mile will own and manage the Phase 1 Welborne heat network, ensuring its efficient operation for the benefit of all residents.
Robin Abram, Associate Director, Last Mile Heat said: “Ambient heat networks – whether using water or ground sources of heat – offer substantial emissions savings, and by adopting and managing the completed network we save developers significant operational expenditure. In many instances we can fund the build of the network too, reducing their upfront cost. As developers across the UK are under pressure to meet emissions reduction targets, Welborne Garden Village is a blueprint for success that many can follow.”
Last Mile Heat, a Heat Trust registered supplier, owns and operates the network and employs a dedicated team utilising 24/7 network monitoring to ensure availability and reliability of the network.
[1] Internal company calculation
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About Last Mile
Last Mile is a multi-utility infrastructure group that designs, builds, owns and manages utility connections at new developments across Great Britain. We are one of the largest independent network owners with more than 850,000 electricity, heat and water connections, an order book of a further 750,000 connections, and over 800 employees.
Our focus is developing efficient, future-proofed infrastructure that delivers reliable electricity, heat, water and wastewater services, working through our Design and Build brands UKPS (operating in the South of England, the Midlands and South Wales) and Energetics (operating in Scotland, North Wales and the North of England). We adopt, operate and maintain utility infrastructure through Last Mile Asset Management on behalf of Last Mile Heat, Last Mile Electricity, Last Mile Gas and Last Mile Water.
Our vision is to lead the delivery of integrated utility infrastructure that meets the needs of new and upcoming residential and commercial developments. We support innovation through pioneering technologies like renewable ground source heat, helping to move our communities forward, future-proof infrastructure and provide a next generation alternative to gas networks.
Backed by blue-chip investors Macquarie Asset Management and Infracapital, we are committed to achieving our long-term growth ambitions by developing, adopting and operating utilities infrastructure that is ready to meet the challenges of net zero, while emphasising financial stability, governance and risk management.
About Last Mile Heat
Last Mile Heat is a joint venture between Last Mile and Rendesco. Through Last Mile Heat we own, operate and maintain decentralised ground source heat networks, customised to each new development and complying with Heat Trust standards.
