Welborne Garden Village secures UK’s largest water-source heat network for entire 6,000 home project

- Plan will see low carbon energy network serve 15,000 residents, as well as commercial premises and community buildings.

- The system, designed and installed by Rendesco, utilises brand new technology and will be the largest heat network of its kind in the UK.

- Residents and businesses will benefit from 90% less CO2 emissions than a gas boiler and 50% less than air source heat pumps.

- Announcement comes as housing developers adjust to the Future Homes Standard which will rule out gas boilers in new build homes from 2025.

The UK’s largest water-source low carbon heating and cooling network is to be installed at Welborne, a new generation sustainable garden village in Hampshire.

The first of its kind technology will initially supply 700 new homes, commercial premises, and community buildings in the first phase of the development. As Welborne expands, it is planned that the network will supply all 15,000 residents in 6,000 new homes with heat, hot water, and cooling.

Rendesco has been commissioned by Buckland Development, the Master Developer of the new community, to deliver the first phase of the network. The network will be owned and operated by Last Mile Heat, the Heat Trust registered low-carbon heat supplier, which is an innovative joint venture between Last Mile and Rendesco.

The first ground breaking system will further bolster the garden village’s impressive sustainability credentials by ensuring that the project has a reliable and sustainable supply of clean heat and hot water, in addition to cooling technology helping to future-proof the project.

The network draws water from Portsmouth Water’s underground Hoads Hill Reservoir, making it significantly more efficient than air source heat pumps due to the more stable and higher average temperature of the reservoir. It will emit 90% less CO2 emissions than a gas boiler and 50% less than air source heat pumps. It is also cheaper for customers, saving an average three-bedroom house around £160 per year compared with an air source heat pump. A unique feature of the network is its ability provide cooling in the warmer months by reversing the process and expelling heat back into the reservoir.  

The network also includes an innovative energy exchange function which allows heat to be transferred between homes and other buildings. When one building is cooling, it can supply its excess heat to other buildings in the network which can then be used for central heating or hot water. As a result, the complete network has the potential to save over 272,000 tonnes of carbon in the first 25 years of operation, compared with gas boilers, which adds up to the emissions of more than 33,000 average homes.

The announcement comes as housing developers adjust to the Future Homes Standard which will ban gas boilers in new build homes from 2025 and will require new build homes to be equipped with low carbon forms of electrified heat such as heat networks or heat pumps. The government recently opened the consultation for the Future Homes Standard in December where they reaffirmed their commitment to electrified sources of heat.


Mark Thistlethwayte, Chairman, Buckland Group, said: “Welborne is a new generation sustainable garden village, so our residents and businesses will rightly expect their buildings to be energy efficient and climate-change resilient. Partnering with Rendesco and Portsmouth Water we are delivering the largest water-source heating and cooling network in the UK, which will cut carbon emissions and reduce people’s energy bills.

“Being involved in Welborne for the long-term both financially and practically, Buckland is taking a different development approach to mainstream house builders. We are designing and developing the community holistically, so we can take strategic decisions to invest in innovative technology and deploy it at scale.”

Alastair Murray, Founder and MD, Rendesco & Director, Last Mile Heat, said:

“We’re proud to be partnering with the Welborne Garden Village development to deliver this exciting and innovative clean energy network to its residents and commercial tenants. It proves undoubtedly that heat networks are the best low-carbon heating and hot water solution for homeowners, businesses and developers.
“Rendesco, together with Last Mile Heat, relishes the opportunity to work with ambitious developers, such as Welborne, who put long-term sustainable living at the forefront of their decision making. With the Future HomesStandard now confirmed for 2025, we are seeing a huge gap opening up between the house builders that are embracing low carbon heating, for the benefits that it offers their customers, and those that are not.
“This project is a template for future housing developments of all shapes and sizes and gives developers the confidence to design their projects, no matter how big or small, around our low carbon heat networks.”


Bob Taylor, Portsmouth Water CEO, said: “We’re incredibly excited to be a partner in what we believe is a first of its kind initiative in the UK. Our collaborative approach with Welborne, Last Mile Heat and Rendesco supports our wider business goals to meet growing environmental and climate change challenges.

“The water that supplies our service reservoir at Hoads Hill comes from an underground reservoir (aquifer) that has the capacity to supply natural energy to the low-carbon heat network serving the development. Longer term, the design principles here are a blueprint for future environmentally led developments right across the UK.”





Note to Editors

Welborne Garden Village:

Welborne is a new generation sustainable garden village in Hampshire. A community for 15,000 people to live, work and play, consisting of connected and energy efficient homes, integrated with extensive publicly accessible green space.

Designed by the Buckland Group, Welborne is a unified vision of one local landowner, invested in the project for the long-term both financially and practically. AsMaster Developer, Buckland is planning, designing and building Welborne holistically, weaving the fabric of a thriving new community, creating sustainable economic, environmental and social value which will last for generations. https://welborne.co.uk


About Rendesco:

Rendesco is the UK’s leading independent clean heat developer and operator. It designs, installs and operates unique low-carbon solutions, which use ground source technology to provide homes and buildings with sustainable heat and hot water. This is a complete network development package, where it provides a full suite of design capabilities and second-to-none installation quality. It manages over 70 networks across the UK which provide heating and hot water for more than 3,000 homes, generating over 14GWh of sustainable heating and valuable operating performance data on ground source heat technology. Further information is available at https://www.rendesco.com.


About Last Mile Heat:

Last Mile Heat is a joint venture between Last Mile Infrastructure (Last Mile), one of the UK’s largest Independent Network Owners and Rendesco (see about Rendesco). Last Mile Heat owns and manages the low-carbon infrastructure, which is designed and built by Rendesco. Further information is available at https://www.lmheat.co.uk.

Last Mile is one of the largest investors in independent utility infrastructure in the UK. It designs, installs, owns and operates electricity, water, sewerage and heat networks as well as providing smart meters to new build properties. It owns and manages approximately 670,000 installed connections and is developing an order book of c. 725,000 connections.


About Portsmouth Water:

Portsmouth Water is one of the oldest water companies in the country, having been incorporated in 1857.

Its high-quality water is derived from the chalk of the South Downs and is abstracted from wells, boreholes, springs and the River Itchen. The Springs at Havant and Bedhampton are thought to be the largest group of springs used for public supplies in Europe.

Portsmouth Water currently serve 324,000 homes and businesses in an area covering 868square kilometres (335 square miles) from the River Meon in Hampshire to the River Arun in West Sussex. Every day it supplies around 170 million litres (37 million gallons) of water to a population of over 720,000 people at the lowest cost in England and Wales.

Portsmouth Water is proud to be rated second in the Customer Measure of Experience (C—Mex) within the water industry in the 2022-23 results.