The update, version 3 of the tool, forms part of the updated . The key update to the Conventions is the addition of site infrastructure, enabling assessments to include roads, utilities and associated works beyond the plot boundary.
Site infrastructure has long been a data black hole, the Hub says, but one the sector needs to address if we are to reduce the embodied carbon emissions of new homes developments. The 2026 update introduces standard scopes for site preparation and infrastructure, providing greater clarity on reporting in a way that works for homebuilders operating across multiple sites.
Together with a range of usability improvements to the Whole Life Carbon Assessment Tool, the update expands the scope of the methodology while making it easier to apply consistently. Under the RICS Whole Life Carbon Assessment Professional Standard (2nd edition), the Conventions provide the sector-specific defaults, assumptions and methodologies needed to support whole life carbon assessments for new homes.
Adam Graveley, embodied and whole life carbon lead at Future Homes Hub, said: "As whole life carbon assessment becomes more widely adopted, consistency becomes increasingly important. Without common assumptions and methodologies, comparing projects or benchmarking performance becomes extremely difficult.
"Site infrastructure has traditionally been a gap in whole life carbon assessment for new homes. By introducing standard scopes for site preparation and infrastructure, the updated Conventions provide greater clarity on reporting while supporting the consistent assessment of developments across multiple sites.
"Together with the updated Whole Life Carbon Assessment Tool, they provide the homebuilding sector with a practical way to deliver more comprehensive, consistent and comparable whole life carbon assessments."
Fabrizio Varriale, built environment analyst, RICS, said: "The RICS Whole Life Carbon Assessment Professional Standard provides the overarching framework for measuring whole life carbon across the built environment. Under that framework, the Future Homes Hub Whole Life Carbon Conventions for New Homes provide the sector-specific defaults, assumptions and methodologies needed to support assessments of new homes.
"Consistency in methodology is fundamental if whole life carbon assessments are to be transparent, comparable and capable of informing better decisions. The Conventions provide the homebuilding sector with a practical route to applying the RICS Professional Standard consistently."