CPD: Verifying with the UK Net Zero Carbon Buildings Standard

The UK Net Zero Carbon Buildings standard is a voluntary standard for new-builds, existing buildings and retrofits that defines clear, measurable requirements for buildings to demonstrate that they are net zero carbon aligned across 13 different sectors.

In March this year, Version 1 of the UK Net Zero Carbon Buildings Standard was published. And in July verification opened, enabling buildings to obtain third-party verification of their performance against the standard’s requirements and therefore be able to claim conformity.

The standard is the industry’s first unified definition for ‘Net Zero Carbon Aligned’ buildings. It is a voluntary standard, created through unprecedented collaboration within the UK built environment industry. 

The built environment accounts for around 40% of the UK’s carbon emissions. The standard’s requirements are science-led and aligned with a 1.5°C climate trajectory, so verifying to the standard demonstrates that a building is playing its part in a net zero carbon UK.

Without independent verification, net zero claims lack credibility. Verified Net Zero Carbon Aligned status proves that performance has been demonstrated in use, eliminating greenwashing. Verifying using the standard’s methodology will establish consistency in building performance reporting, enabling credible like-for-like comparison of assets, and clear differentiation for those meeting the standard, who will demonstrably be market leaders in sustainable buildings.

Verification builds investor confidence, providing assurance to asset owners, designers, funders, investors, developers – anyone involved in the UK real estate market who wants to robustly prove their building is net zero.

The standard is focused on in-use, measured performance and is backed by building data and science-led modelling. The standard covers both the definition of a Net Zero Carbon Aligned building as well as the methodology to measure and report a building’s carbon and energy performance.

Laying out the requirements, methodology and metrics provides professionals in the UK built environment with a consistency hitherto lacking in building performance reporting. Furthermore, the metrics are those already familiar to UK industry; what is new is the way that the standard brings them together to characterise net zero carbon building performance.

The standard covers 11 aspects using the metrics that are crucial for net zero carbon building performance. This is conveyed through a number of mandatory limits, targets and requirements including:

It specifies the approach to carbon accounting, reporting and submitting of evidence as well as the optional methodology for offsetting residual carbon emissions. Notably, optional offsetting can only be pursued after all the requirements of the standard have been met, so offsetting cannot be used to make up for poor performance against the limits.

To demonstrate these requirements have been met, measured in-use building data must be submitted for third-party verification.  

When verifying a building to the UK Net Zero Carbon Buildings Standard, there are three different routes available.

1. In-Use Verification: Net Zero Carbon Aligned. This is the purpose for which the UK Net Zero Carbon Buildings standard was created: to robustly verify that buildings are Net Zero Carbon Aligned.

Buildings achieving this designation meet all the requirements of the standard and are achieving lower-carbon outcomes in line with the UK’s legally binding carbon budgets and targets.

2. In-Use Verification: Performance Evaluation. Performance evaluations enable buildings to verify performance against the standard’s requirements, even if they are not meeting all of them.

Both in-use verification routes can be pursued as a whole building or using a landlord-only or tenant-only approach for applicable sectors.

3. Practical Completion ‘On Track’ verified checks. Verified checks may be carried out at practical completion to determine whether a building is ‘On Track’ to meet the requirements of the standard when in-use.

Undertaken within six months of practical completion, it is optional to pursue On Track and it is not a pre-requisite for in-use verification. The On Track statement may be useful for project sign-off or handover. It requires independent, third-party verification in the same way as the in-use verification routes.

Buildings achieving Practical Completion On Track are not Net Zero Carbon Aligned and are committed to undergoing full, in-use verification once occupied. Practical Completion On Track is available at a whole building level only.

Additionally, there is the ‘Deeming to Satisfy’ route.

Deeming to Satisfy aligns the standard with established, market-recognised rating systems and schemes, reducing the need for duplicate assessments and submissions. Achievement of schemes that have been Deemed to Satisfy can be used as evidence of meeting specific requirements of the standard.

Within Version 1, NABERS UK Energy for Offices and Passivhaus have been Deemed to Satisfy certain aspects of the standard, providing additional pathways to conformity. Additional routes that are Deemed to Satisfy are being explored.

Bureau Veritas is the standard’s verification administrator. Bureau Veritas worked collaboratively with Net Zero Carbon Buildings Standard Ltd to produce the verification framework and methodology, ensuring the highest standards of governance.

In the role of verification administrator, Bureau Veritas oversees and manages the verification scheme, including governance, verifier training and accreditation and quality assurance.

To undergo verification, evidence must be submitted for each of the standard’s requirements, including its pass or fail limits and mandatory reporting requirements. The evidence submission must include the standard’s submission proforma (downloadable from nzcbuildings.com), filled out with the building’s data.

The earlier that the standard is identified as a project objective, the easier it is to meet. This was the overarching message from the standard’s Pilot Testing (carried out in 2025), which indicated that starting to collect data early; identifying a data manager responsible for collecting and organising the submission data; and working collaboratively across disciplines made the process more efficient.

During the verification process, an approved verifier reviews the evidence to confirm that the standard’s requirements have been met. The verifier will check for data gaps and return queries to the claimant (the person or organisation submitting the building for verification). Verifiers undergo specific training and will apply expert knowledge to affirm the quality of the evidence, and whether it substantiates the claim.

Project teams pursuing verification and conformity to the standard should ensure that building data, such as upfront and embodied carbon calculations, is well managed, stored, and made available in the right format.

Verification is carried out on whole buildings across all the standard’s 13 sectors. For offices, landlord spaces or tenancies can also be verified independently, if it is not possible to pursue a whole building approach.

Conformity claims to the standard can only be made once 12 months of measured operational performance data is available at the required occupancy level.

The standard shifts focus from design intent to measured outcomes, supporting credible net zero claims. Verifying buildings as Net Zero Carbon Aligned demonstrably proves that they are playing their part in a net zero UK and sets a benchmark for the industry.

Katie Clemence Jackson is CEO of Net Zero Carbon Buildings Standard Ltd.