The UK Net Zero Carbon Buildings Standard (“the Standard”), developed through collaboration between CIBSE, BBP, BRE, the Carbon Trust, IStructE, LETI, RIBA, RICS, and UKGBC is a free-to-access technical standard that will enable the built environment to robustly prove that built assets are playing their part to decarbonise in line with the UK’s carbon and energy budgets.
Until this point, there has been no single, agreed methodology for defining what ‘net zero carbon’ means for buildings in the UK. This voluntary standard provides a set of consistent rules to create a level playing field around the meaning of net zero carbon.
Version 1 builds on the Pilot Version released in September 2024, and contains the technical details on how a building should meet the Standard including what limits and targets it needs to meet, the technical evidence needed to demonstrate this, how it should be reported, how it must be verified, and the ways its verified status can be communicated.
Katie Clemence-Jackson, CEO of UK Net Zero Carbon Buildings Standard said: “The Standard will provide much-needed clarity and consistency to net zero carbon claims, combating greenwashing, and providing a robust definition for the industry to rally towards. Version 1 incorporates the feedback from our Pilot Testing Programme, plus new Annexes that further support its implementation, all of which will make it easier and clearer to target and implement the Standard. The publication of Version 1 is an important milestone for the Standard, and paves the way for the UK built environment to understand, measure and reduce its carbon emissions in line with the UK’s climate targets. With verification soon to become available, it’s only a matter of time before the first officially Net Zero Carbon Aligned Buildings are verified, and we can’t wait.”
What has changed since the Pilot version?
While the core of the Standard is much unchanged from the Pilot version, the UK Net Zero Carbon Buildings Standard’s team has listened carefully to feedback on the experience of the industry in applying the Pilot Version . Alongside a number of technical amendments to the Standard in response to feedback, new sections in Version 1 include:
A new Annex on Landlord only or tenant only routes, which provides details on how landlords or tenants in the office sector may approach meeting the Standard solely for their part of a building, where whole building verification is not possible.
A new Annex called “PC On track”, which sets out optional, verified checks that can be carried out at practical completion (PC) to predict whether the building is on track to meet the Standard once occupied and in-use. This may be used as an additional step to pursuing conformity with the Standard, but on its own does not allow conformity claims to be made.
An Annex on Deeming to Satisfy (previously “Equivalence”) This aligns the Standard with established and market recognised schemes. Achievement of schemes that have been Deemed to Satisfy can be used as evidence of meeting specific requirements of the Standard, reducing the need for duplicate assessments. For Version 1, the Annex will include mappings to NABERS UK and Passivhaus, and further mappings will be announced as and when they are agreed.
Finalised sections on Verification and Communication. Sections of the Standard covering verification, and how to communicate claims, will cover the Standard’s requirements, while the framework and methodology of verification is currently being developed with Bureau Veritas, the company working with NZCBS Ltd. to develop the verification framework, and soon to be appointed into the role of the Standard’s Verification Administrator.
Update to limits. The Standard’s limits have been reviewed following industry feedback, with particular attention to those sectors where less supportive responses were received on the achievability of the limits during the Pilot Testing Programme. The final limits have been set within the context of refined evidence and data, whilst remaining within a 1.5°C trajectory for the UK built environment as a whole, based on the Standard’s balanced scenario modelling.
A document explaining the full scope of changes since the Pilot Version is published alongside Version 1.
Ellie Burkill, Chair of the UK Net Zero Carbon Buildings Standard Technical Steering Group said: "The Pilot Version of the Standard was a product of unprecedented industry collaboration, and we are thrilled to have seen this momentum continue into Version 1. Feedback received from our Pilot Testing and the wider industry has been pivotal in ensuring Version 1 is fit for purpose, while maintaining its fundamental principles and grounding in performance-based outcomes. We are delighted to be publishing Version 1, which incorporates a number of technical amendments and new Annexes in direct response to feedback received. Reaching this milestone is a testament to the dedication of the industry in applying the Standard and sharing their feedback, our Technical Steering Group’s commitment to listening and responding, and the incredible group of volunteers who have continued to support us."
Coming up: Verification Becomes Available
Verification will become available in Q2 of 2026. Once it is launched, it will be possible to appoint a verifier and go through the process to be able to robustly say that a building is Net Zero Carbon Aligned. Full information on the process and methodology will be shared on the UK NZCBS website once verification becomes available.
Buildings undergoing verification will need to submit information to the verifier to evidence each of the requirements within the Standard. Alongside Version 1, a Verification Primer has been published which provides the latest overview of the steps of the verification process, roles and responsibilities, evidence requirements, programme and costs.
