Comparing whole life carbon assessments across new housing developments is set to become more consistent following the publication of updated Whole Life Carbon Conventions for New Homes from the Future Homes Hub, alongside Version 3 of its free Whole Life Carbon Assessment Tool.

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, 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.

As whole life carbon assessment becomes increasingly embedded within the homebuilding sector, the need for a consistent approach has never been greater. Different assumptions, data sources and calculation methods can produce significantly different results, making it difficult to compare projects fairly, benchmark performance and make informed decisions about reducing embodied carbon.

The Whole Life Carbon Conventions provide a shared reference point for assessing new homes, helping to ensure results are comparable regardless of which consultant, assessor or software tool is used. Together with the updated Whole Life Carbon Assessment Tool, they provide a practical way to apply the methodology consistently across projects.

The updated Whole Life Carbon Assessment Tool has been developed to reflect the latest Conventions and includes improvements to usability and the overall user experience. It remains the first tool to provide a dedicated pathway for homebuilders, designers and consultants to estimate the embodied carbon emissions associated with site preparation and infrastructure for new homes developments.

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."

To support organisations in adopting the updated methodology, the Future Homes Hub is hosting a webinar on 27th July exploring how the updated Conventions and Whole Life Carbon Assessment Tool can be applied in practice. The session will cover:

• How the Future Homes Hub Conventions align with the RICS Whole Life Carbon Assessment Professional Standard
• The addition of site infrastructure to the Conventions, what it means for assessments and how to apply it using the updated Whole Life Carbon Assessment Tool
• The role of generic defaults, assumptions and Environmental Product Declarations (EPDs)
• Practical guidance on specifying the Conventions within project briefs and assessments

View the updated Whole Life Carbon Conventions for New Homes: 

https://knowledge.futurehomes.org.uk/resource/whole-life-carbon-conventions-for-new-homes/

View Version 3 of the Whole Life Carbon Assessment Tool: 

https://knowledge.futurehomes.org.uk/resource/future-homes-carbon-assessment-tool/

Developers, consultants, assessors and sustainability professionals are encouraged to begin applying the Conventions and Assessment Tool within their organisations and projects.