The Future Buildings Standard is defined by a set of official documents published by the Ministry of Housing, Communities and Local Government (MHCLG). This page collects the key resources that practitioners need when working with the FBS, from the primary legislation to the calculation tools and software.
Each resource below includes a brief description of what it covers and why it matters. All links point to official government sources or approved industry tools.
Approved Document L Volume 2 (2026)
The primary technical guidance document for non-domestic building energy performance under the Future Buildings Standard. Published on 24 March 2026, it replaces the 2021 edition and sets out the requirements for fabric performance, heating systems, solar PV, lighting, ventilation, and overheating mitigation. This is the document that practitioners will refer to most frequently.
Download Approved Document L Volume 2 (2026 edition) (PDF)
Building Circular 01/2026
The official communication from MHCLG to local authorities and approved inspectors explaining how the Future Homes and Buildings Standards should be implemented. It covers transitional arrangements, enforcement dates, and the interaction between the new and existing regulations. Essential reading for understanding when the FBS applies to a given project.
Read Building Circular 01/2026 on GOV.UK
Consultation response
The government's response to the 2023 Future Homes and Buildings Standards consultation. This document explains the reasoning behind the final policy decisions, including which consultation proposals were adopted, modified, or rejected. It provides valuable context for understanding why specific requirements were set at their current levels.
Read the consultation response on GOV.UK
For our summary of the key decisions, see the consultation response analysis.
Impact assessment
The Regulatory Policy Committee's independent assessment of the costs and benefits of the Future Homes and Buildings Standards. Covers the expected impact on construction costs, energy savings, carbon reductions, and the broader building industry. Useful for developers and project managers building business cases for FBS-compliant designs.
Read the impact assessment on GOV.UK
NCM and iSBEM
The National Calculation Methodology (NCM) is the approved method for calculating the energy performance of non-domestic buildings in England and Wales. iSBEM is the government's free interface software for the Simplified Building Energy Model (SBEM), which implements the NCM for straightforward buildings. The UK-NCM website hosts the latest versions of iSBEM, the NCM modelling guide, and supporting databases.
For guidance on using SBEM, see our What is SBEM? page.
Approved dynamic simulation software
For buildings that are too complex for SBEM – such as those with advanced HVAC systems, atria, or mixed-mode ventilation – an approved Dynamic Simulation Model (DSM) must be used. The list of approved DSM software is maintained on GOV.UK and includes tools such as IES VE and TAS. Always check that you are using a version approved for the 2026 edition of Part L before submitting compliance calculations.
For more on when DSM is required, see our dynamic simulation modelling page.
HEM Guide – domestic compliance
The Future Buildings Standard covers non-domestic buildings. For domestic buildings, the equivalent regulations fall under the Future Homes Standard, which uses the Home Energy Model (HEM) instead of SBEM. Our sister site, the HEM Guide, provides the same practitioner-led coverage for domestic compliance.
For a comparison of the two standards, see our FBS vs FHS page.
How to use these resources
The documents above form the official foundation for non-domestic building compliance under the Future Buildings Standard. When working on a project, start with the Approved Document L Volume 2 for the technical requirements, refer to the Building Circular for transitional arrangements, and use iSBEM or an approved DSM tool to produce your BRUKL compliance report.
Throughout this guide, we provide page-by-page analysis of these source documents with inline citations so you can trace every claim back to its official source.
Frequently Asked Questions
Where can I download Approved Document L?
Approved Document L Volume 2 (2026 edition) is available as a free PDF download from GOV.UK. It covers all energy performance requirements for new non-domestic buildings under the Future Buildings Standard.
What software do I need for SBEM?
iSBEM is the government's free interface software for the Simplified Building Energy Model. It is available from the UK-NCM website (uk-ncm.org.uk). For complex buildings requiring Dynamic Simulation Modelling, you will need approved software such as IES VE or TAS.