UK Net Zero Carbon Buildings Standard sets out unified framework for operational buildings

The first version of the new UK Net Zero Carbon Buildings Standard has now been published, following publication of the pilot standard in April 2025. This first version is accompanied by a summary of updates which have been made since the pilot. 

What is the standard?

The standard has been developed by a collaboration of industry stakeholders, including RICS and RIBA. It is currently voluntary, but aims to create a unified definition of "Net Zero Carbon Aligned Buildings" to support the wider drive to reduce carbon emissions and specifically to ensure that the UK's built environment sector does not exceed its own share of national carbon and energy budgets. 

What buildings are within scope?

The standard can be applied to any "building-related construction works" and the use of buildings within the UK. Applicability is determined by the use of buildings in a wide range of sectors, which include:

• Commercial residential (such as student accommodation or care homes).
• Culture, entertainment, sport and leisure.
• Data centres.
• Healthcare.
• Higher education and schools.
• Homes, hotels, retail and offices.
• Science and technology.
• Storage and distribution.

It is not applicable to any buildings outside of the UK, assets that cannot be considered "buildings", and any buildings that are not within the specified sectors.

Critically, achieving the "Net Zero Carbon Aligned Building" accreditation is earned through demonstrated, in-use performance, not through design-stage modelling alone. This means the standard is only applicable to completed works and fully operational buildings and cannot be applied during the design and construction phases.

What are the metrics and requirements?

Under the standard there are several "mandatory" requirements that need to be tracked against specified metrics to show conformity (noting that the standard itself is voluntary), with a further two requirements that are currently not mandatory but may become so in future iterations.

The mandatory elements that must be tracked for conformity with the standard are:

• Embodied carbon: a combination of "life cycle embodied carbon" (LCEC) and "upfront carbon". LCEC includes the total greenhouse gas (GHG) emissions and removals that are associated with the construction products and processes used over a building's life cycle (which includes its maintenance and disposal). Upfront carbon refers to the carbon contained within the materials used in construction, based on their generic specifications.
• Operational energy: all energy used by a building over its "in-use" lifecycle, including any renewable energy or heat generated by the site itself.
• On-site renewable electricity generation: the total energy generated by a site, as well as the total renewable energy generated that is actually used by the building itself.
• Fossil fuel free: confirmation must be given that no fossil fuel is used on site, except in limited circumstances that are exempt.
• District heating and/or cooling: where relevant, the energy used by a district energy scheme and carbon emissions associated with heating/cooling.
• Refrigerants: the annual carbon impact of refrigerant leakage for GHGs covered by the Kyoto protocol and an additional optional element covering the annual carbon impact of refrigerant leakage of other GHGs.

The additional voluntary elements are:

• Operational water use: covering both annual operational water use and annual operational water carbon emissions.
• Electricity demand management: date and time metrics of electricity demand.

There are also options for carbon offsetting, the detailed rules for which are set out in the standard.

Each reportable requirement is accompanied in the standard with detailed information on which metrics need to be met in order to comply. All targets are in Appendix A. 

What does conformity look like? 

The standard sets out that entities may approach conformity with it either as a whole building, or alternatively by taking a landlord- or tenant-only approach.

In order to demonstrate conformity, entities will be required to have their assessment and final submission verified by a third-party before being accredited. While the standard does not provide a list of approved third-party verifiers, it does include a list of required verifier competencies.

A building's first verification must take place as soon as possible after the "Reporting Period End Point", being a date falling more than one year after the building reaches minimum occupancy. Minimum occupancy is defined, for buildings which are intended to be occupied or partly occupied, achievement of an occupancy rate of over 80% of total possible occupancy.

Re-verification should occur annually for at least two years after the first verification. Once a building has been verified in three sequential years and there have been no additional works undertaken in relation to the building, re-verification should occur every three years.

The standard makes it clear that it is prohibited to make, publish or imply any claims of conformity with it or verification of meeting the standard unless all formal processes have been correctly followed. 

Are there any parallels with European markets? 

While the standard is not an international collaboration using internationally recognised approaches, there are other markets introducing similar approaches across Europe. These range from legislative standards that are mandatory (or are set to become so) to industry-approved standards, which are voluntary.

On an EU level, the Energy Performance of Buildings Directive aims to reduce the carbon impact of new and existing buildings with phased carbon limits being introduced and an overall aim of achieving "a zero-emission building stock by 2050".

On an individual Member State level, France (via the Réglementation Environnementale 2020 (RE2020)) and Denmark (via Building Regulations (BR18)) have the most analogous and mature regulations on building efficiency standards. The RE2020 introduces requirements which aim to reduce emissions through a buildings "construction lifetime" (from initial construction to demolition) and the BR18 uses a sector-based approach to introduce phased, science-aligned carbon limits across the building life cycle (including during operation).

In addition to these legislative standards, there are also industry-led approaches which are more aligned to the standard. The DGNB Framework for Carbon Neutral Buildings and Sites (developed in Germany, but used in other Member States) provides the basis for developing "building specific" climate strategies and the Low-Carbon Building Initiative aims to measure how buildings affect the climate, and ensure that these assessments are robust and complete throughout the whole life cycle.

Other standards across Europe also contain elements similar to parts of the standard, including BREEAM and Milieu Prestatie Gebouwen or "MPG" in the Netherlands. 

Osborne Clarke comment

While the standard is not currently mandatory, it is likely that interested stakeholders (such as lenders, landlords and corporate occupiers) will begin to see it emerge at all levels of a building lifecycle: whether funding, construction or asset management. In recent years the property sector has been struggling to find consistency on how to measure sustainability and net-zero pathways on buildings and their use. The standard has the potential to give the sector some much-needed certainty and uniformity in this area.

For entities looking to certify any works, the questions to begin addressing are: which assets are candidates for verification; what data collection and metering infrastructure is in place or needed; and what ownership structures enable (or obstruct) access to whole-building data.

 Adam Budd, trainee solicitor at Osborne Clarke, assisted with this Insight.