Approved Document L: Conservation of fuel and power / Energy and greenhouse gas emissions
England-focused reference checklist
Editorial source review: 2026-10-17
https://saeedazarshab.com/articles/england-building-regulations/approved-document-l/

INDEPENDENT GUIDANCE — not project-specific legal/design advice or a compliance certificate. Check the official current requirements and applicable transition.

Part L concerns building energy performance and services. Requirements differ with building type, new or existing work and the applicable edition. Fabric, airtightness, ventilation, heating, controls and the relevant assessment must be coordinated. A product U-value or an energy-model result alone does not establish that the completed building meets all requirements.

WHAT TO CHECK
[ ] Record why a particular edition and transitional regime apply to the project.
[ ] Identify the assessment and supporting evidence required for the building and type of work.
[ ] Coordinate thermal details and services with ventilation, moisture, overheating and fire safety.
[ ] Keep changes aligned with the energy design and arrange applicable installation and commissioning checks.
[ ] Retain the final assessment, test results and user information for the building as constructed.

RECORDS TO KEEP
- Energy assessment, assumptions and coordinated specifications
- Applicable installation, commissioning and test records
- Final compliance evidence and user information

WHEN TO GET SPECIALIST HELP
Use competent energy-assessment and design advice for the applicable route. Verify current dates on the official source before making a specification or promising compliance.

SCOPE AND EDITION
Main landing retains 2021 edition with 2023 amendments. Separate 2026 Energy and greenhouse gas emissions volumes were published 24 March 2026 and corrected 8 September 2026. Main commencement is 24 March 2027; relevant HRB provisions 24 September 2027, with transitions. Use the edition applicable to the building, not simply the newest PDF. Published 2026 guidance is not automatically the standard already applicable in October 2026. Check notice/application dates, defined commencement and project/HRB transitional arrangements.

OFFICIAL SOURCES
GOV.UK — Approved Document L
https://www.gov.uk/government/publications/conservation-of-fuel-and-power-approved-document-l

Approved Document L (2026)
https://www.gov.uk/government/publications/approved-document-l-2026

Future Homes and Buildings Standards: Building Circular 01/2026 letter
https://www.gov.uk/government/publications/the-future-homes-and-buildings-standards-building-circular-012026/the-future-homes-and-buildings-standards-building-circular-012026-letter

Contains public sector information licensed under the Open Government Licence v3.0, except where otherwise stated. Original practical summary by Saeed Azarshab.
https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/