UK Net Zero Carbon Buildings Standard opens PC-on-Track verification to pre-Version 1 completions

The UK Net Zero Carbon Buildings Standard (UKNZCBS) has extended its PC-on-Track verification window to buildings completed between 1 March 2025 and 31 March 2026, giving projects finished before Version 1 was published a route to demonstrate alignment.

PC-on-Track verification is normally carried out within six months of practical completion, CIBSE said in announcing the change on 6 October. It confirms that a building is on track to meet the Standard's net zero carbon requirements once it is in use.

The extension was introduced to improve access for buildings that reached completion before Version 1 of the Standard came out in March 2026, according to CIBSE, one of the bodies that developed it.

When verification first opened on 28 July, Antoine Giros, Vice President, UK and Ireland, Bureau Veritas, said: "The launch of verification under the UK Net Zero Carbon Buildings Standard marks a pivotal shift in the industry, moving from predicted outcomes to measured, independently verified in-use performance."

The deadlines

Building owners and project teams wanting to use the extended window must register their building by 23 December 2026, CIBSE said. UKNZCBS is encouraging interested parties to begin promptly because there can be a lead time between submitting a registration application and completing registration.

The Standard's new Planned Updates page, published by Net Zero Carbon Buildings Standard Limited, logs the extension as change CH001, amending clause E2-6.2.3. It adds a second condition: eligible buildings must also appoint a verifier by 1 April 2027.

Registration is with Net Zero Carbon Buildings Standard Limited. Once a building is registered, a quote for verification can be obtained from Bureau Veritas, according to CIBSE's July announcement.

How PC-on-Track fits

PC-on-Track is an optional check, the Standard's verification routes page says, and is not a prerequisite for in-use verification. Full verification evidence, according to CIBSE, requires 12 months of in-use energy data together with as-built upfront embodied carbon data.

Bureau Veritas is the Verification Administrator. In that role it runs and oversees the verification scheme and also acts as the first verifier, with wider verifier training and accreditation due to open to the industry in 2027.

Further changes planned

The extension is the first of several updates set out on the new Planned Updates page. A second logged change, CH002, will amend clause 4.1.2 to state that buildings are registered to the version of the Standard in effect at the point of registration, so that a building is expected to meet the limits of the version to which it is registered.

The page distinguishes between clarifications, which add clarity on how to use or interpret the Standard without changing requirements, and changes, which do alter requirements.

A revised Version 1.2 is planned for late 2026, incorporating updates based on initial responses to Version 1, the Standard's publisher said.

Background

A Technical Steering Group with a representative from each founding organisation was set up in May 2022, according to the Standard's own history page. The Pilot Version followed in September 2024, and Version 1 was published in March 2026 after input from more than 350 industry experts, CIBSE said.

CIBSE's October announcement names the developers as CIBSE, Better Buildings Partnership (BBP), BRE, the Institution of Structural Engineers (IStructE), LETI, RIBA, RICS and the UK Green Building Council (UKGBC). The technical standard is free to access.

At the Version 1 launch, 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."

Buildings completed in the eligible window have until 23 December 2026 to register and until 1 April 2027 to appoint a verifier.