Approved Document L2 2026 published ahead of Future Buildings Standard implementation in 2027
The Government has now published Approved Document L, Volume 2: Buildings other than dwellings (2026), providing the clearest indication yet of how the Future Buildings Standard (FBS) will be delivered in practice for non-domestic buildings in England.
The release of the updated guidance marks a significant milestone for the industry, translating long-standing policy into the technical requirements that designers, developers and energy assessors will need to follow. It confirms the direction of travel toward highly efficient, low-carbon buildings and provides early visibility of the standards that will soon become mandatory.
Crucially, the Government has now confirmed that the Future Buildings Standard will come into force on 24th March 2027 for non-higher-risk buildings, giving industry a defined timeline to prepare for implementation.
Elmhurst has provided an overview of what we know based on the announcements and publications released by government earlier this week (24th March 2026).
Low-carbon heating becomes central to compliance
One of the most significant themes reinforced through the updated guidance is the shift toward low-carbon heating. The Future Buildings Standard is designed to move typical new non-domestic buildings away from fossil-fuel heating and toward technologies such as heat pumps and low-carbon heat networks. This represents a fundamental change in how buildings are designed and assessed, with heating strategy playing a much more decisive role in compliance.
Higher expectations for performance and compliance
The Future Buildings Standard will continue to use key performance metrics such as carbon emissions and primary energy, but with significantly tighter targets, creating a more demanding compliance framework.
Updated notional building specifications will set a higher benchmark through stronger fabric standards, more efficient building services and a clear trajectory toward low-carbon heating. Government proposals and modelling also indicate a greater role for on-site renewable generation, with increased use of solar PV within non-domestic notional building assumptions compared to Part L 2021.
As a result, designs that fall short in any one area will find it much more difficult to achieve compliance, reducing the flexibility previously available under earlier standards.
Alongside this, updated SBEM methodology and DSM modelling tools will increase the level of detail required in energy assessments, placing greater emphasis on accuracy and early-stage analysis.
How this differs from Part L 2021 Uplift
While Part L 2021 introduced a meaningful uplift in performance, it was always intended as an interim step toward the Future Buildings Standard. The updated guidance makes it clear that the next phase represents a more fundamental shift in both design expectations and compliance outcomes.
| Standard | Requirements |
| Part L 2021 | ~27% CO₂ reduction vs 2013; gas heating often still compliant |
| Future Buildings Standard 2025 | Zero-carbon ready new non-domestic buildings; stronger fabric and services, low-carbon heating, and greater use of on-site renewable generation |
Under Part L 2021, compliance could still be achieved using gas heating systems alongside moderate improvements to fabric and building services. In contrast, the Future Buildings Standard moves the industry toward buildings that are “zero carbon ready”, with a much stronger emphasis on low-carbon heating, high-performance fabric and overall energy efficiency.
This differs sharply from the Part L 2021 notional building, where gas heating and more moderate fabric performance could still achieve compliance. As a result, designs that rely on gas boilers, weaker fabric or limited use of renewables are far more likely to struggle under the Future Buildings Standard.
What does this means for Non-Domestic Energy Assessors (NDEAs)?
At present, NDEAs will be unable to model and see what impact the changes outlined in Approved Document L2 (2026), as an update has not yet been made to the SBEM calculation methodology. Elmhurst will keep its members informed as and when this is due to take place.
However, it remains clear that for NDEAs working on new build commercial projects delivered under the Future Buildings Standard, they will experience a major shift in how compliance will be demonstrated. Tighter targets, revised calculation tools, updated notional buildings and a stronger emphasis on low-carbon design will increase the technical demands of assessment and draw assessors further into design-stage decision-making.
This will mean:
- More complex modelling
- Greater involvement at the design stage
- Increased demand for low-carbon expertise
- More input into design decisions
As a result, assessors will play a key role in helping clients understand and meet the requirements of the Future Buildings Standard.
Elmhurst’s Non-Domestic Scheme Manager, John Robinson, welcomes the government’s continued commitment to transitioning the UK’s building stock toward zero‑carbon‑ready performance.
The shift from Part L 2021 to the Future Buildings Standard will transform non‑domestic EPC modelling. Assessors will see more complex calculations, more design‑stage demand, and intensified focus on fabric and low‑carbon heat. This represents a major opportunity for skilled NDEAs to support clients through compliance, design optimisation and retrofit planning.”
Elmhurst will continue to support assessors through updated SBEM training, FBS modelling guidance, refresher CPD, client-facing resources and ongoing technical support.
As the Government progresses toward full implementation of the Future Buildings Standard in 2027, Elmhurst is committed to ensuring members are well prepared to understand the changes and confidently lead the transition.