New study shows Saint-Gobain and Barratt Redrow concept house significantly reduces upfront carbon emissions

Saint-Gobain UK has released a new detailed independent study that reveals the innovative concept eHome2 saves between 8 - 9.5 tonnes of embodied carbon emissions compared to traditionally built homes*. 

The new study, is an independently written and third-party verified Whole Life Carbon Assessment (WLCA) assesses the whole-life embodied carbon emissions, with analysis drawn on upfront embodied carbon (emissions associated with manufacturing and installing materials), of the innovative eHome2 concept, built in partnership with Barratt Redrow at the world-leading Energy House 2.0 climatic chamber at the University of Salford. 

The eHome2 was constructed in 2023 as a unique collaboration between Saint-Gobain, Barratt Redrow and the University of Salford. It was designed and built to be a high-performing 3-bedroom house, achieve net-zero carbon for regulated energy use, and demonstrate how homes can be constructed at scale to meet the Government’s Future Homes Standard. 

The WLCA was carried out independently by Focus Consultants, alongside Saint-Gobain’s LCA Team and panel reviewed by eLoop. It compared the eHome2’s lightweight off-site manufactured timber-frame construction approach with other alternative build approaches, including traditional brick and block construction**. 

Barratt Redrow is supporting the research as part of its work to achieve net zero greenhouse gas emissions by 2040 – the first major housebuilder to do so. 

Key findings from the study, where eHome2 is compared to traditionally built masonry home using clay bricks and PIR insulation, show

• A 11% reduction in whole life embodied carbon (over 60 years).
• A 21% reduction in upfront embodied carbon (excluding biogenic carbon) emissions —equating to over 10 tonnes of CO₂e savings per house.
• A 57% reduction in upfront embodied carbon when biogenic carbon is included—representing the benefits of sustainably sourced timber.
• Lighter construction reduces emissions related to reduced concrete foundations by approximately 1 tonne of CO₂e, due to the reduced load requirements of the timber-frame, lightweight façade system – Enveovent developed by Saint-Gobain during the construction of eHome2. 
• The external walls, timber frame fabric and foundations contribute only 16% of the total carbon footprint of the building compared to 26% under traditional construction, over the building’s lifespan. 

This new study confirms the potential for lightweight timber-frame modern off-site construction solutions to not only produce high-performing buildings at scale and speed but also significantly reduce embodied carbon emissions of new homes.

From the testing carried out by the team at the University of Salford, eHome2 has already demonstrated its capability to maintain comfortable internal temperatures with “zero carbon-ready” heating systems for less than £2 a day when the temperature is 5 °C (see published report: https://salford-repository.worktribe.com/output/2313140). Combining this with the new LCA results, it further demonstrates how construction can reduce its environmental impact whilst providing comfortable homes for residents at scale.

MIKE CHALDECOTT, CEO of Saint-Gobain UK & Ireland commented:

“The development of eHome2, in collaboration with our partners Barratt Redrow, has again demonstrated the significant role lightweight construction made with high levels of off-site construction can create high-performing and lower carbon homes at scale. At a time of significant Government ambition for new housebuilding for both the private and public sectors, eHome2 has proven to be a research facility to help shape a transforming construction industry. The build has played a key role in helping us shape low-carbon solutions for new housing. These solutions are now being tested in the field in pilot social housing schemes and are being fully industrialised in preparation to support large-scale housing growth in the UK.”

.* The WLCA looked at the building’s performance over their assumed 60 years life-span.

** Note - in the published executive summary of the study, eHome2 is compared with two most relevant built approaches only.   

For further questions about the WCLA or for more detail please contact: [email protected]

Note on Biogenic Carbon: Carbon that is associated with biological materials. It may be sequestered, for example, through photosynthesis by growing trees in a sustainable forest plantation, which are subsequently harvested to manufacture construction products. 

Biogenic carbon may also be emitted, for example, due to combustion of waste timber, to provide heat and/or generate electricity. Including biogenic carbon sequestration has the effect of lowering upfront carbon. At end-of-life, the sequestered carbon dioxide in a material is either emitted, for example through incineration, or is accounted as returning to atmosphere if the material is reused, recycled or landfilled. When results exclude biogenic carbon, they are termed as “gross” emissions, and “net” emissions when biogenic carbon is included.