We hope you have seen that the Future Homes and Buildings Standards have landed in the shape of revisions to AD L1 and AD L2, as well as AD F.
We set out in the box below some of the main changes to AD L and we will provide more detailed guidance via our Technical Committee in the coming weeks.
Meanwhile, a link to the documents can be found here:
https://www.gov.uk/government/consultations/the-future-homes-and-buildings-standards-2023-consultation
This gives the government’s responses to the 2023/24 Future Homes and Buildings Standards consultation, along with the revised Parts L and F of the Building Regulations.
- ADL1:2026 and ADL2:2026 approved documents take effect on 24 March 2027 for use in England for building work that is not in connection with higher-risk building work. They take effect on 24 September 2027 for use in England for building work that is in connection with higher-risk building work. there is a 12 month transition period.
- To calculate the energy performance of a new dwelling, there are two methodologies which have been developed for this purpose, which are as follows:
- The Home Energy Model (HEM) – which is new & its launch has been delayed.
- The Government’s Standard Assessment Procedure for the Energy Rating of Dwellings (Standard Assessment Procedure or SAP).
- The full properties of the notional building (dwellings) can be found in the following:
- For the HEM methodology: Tables 1 and 3 of The Future Homes Standard 2026: dwelling notional buildings.
- For the SAP methodology: Appendix R of the SAP 10.3 specification.
- For new dwellings, the U-value of a window or door should be determined using one of the following (see Section 3):
- Direct measurement by hot-box as set out in BS EN ISO 12567-1 for windows and in BS EN ISO 12567-2 for roof windows.
- Calculated using the actual size and configuration of the window or door in line with BS EN ISO 10077-1 and BS EN ISO 10077-2.
- i.e. NO calculation using “standard” window sizes from EN 14351-1 for new dwellings as in 2021.
- For new dwellings, determination of a window or door U-value is now to include additional elements where present (e.g. sills, add-ons, dummy transoms) – see paragraph 3.3 of ADL1.
- The limiting and notional U-values for windows, doors and curtain walling have not changed from 2021, but there are important changes and details to note.
- For new Dwellings, while the notional U-value for a window is 1.2 W/m2K, area-weighted average values for the dwelling can still be used.
- For existing dwellings, the U-value of a window or door should be determined using one of the following:
- Calculated using the actual size and configuration.
- “Standard” sizes from EN 14351-1, with the actual configuration or a “standard” configuration as set out in ADL1.
- This has not changed from ADL1:2021.
- To calculate the energy performance of a new building other than a dwelling, software packages can be either:
- the Simplified Building Energy Model (SBEM); or
- other approved software packages (see www.uk-ncm.org.uk)
- This has not changed from ADL2:2021.
- For determining U-values of windows and doors in buildings other than dwellings:
- The allowable methods have not changed from ADL2:2021.
- The notional and limiting U-values for fenestration-related elements remain unchanged in the 2026 versions of ADL compared to the 2021 versions.
- Alongside the changes to thermal performance, updates to Approved Document F covering ventilation have also been published, although the changes won’t affect how the fenestration industry currently complies with AD F.
- The updated AD F includes additional guidance on Maintenance, Ducting and Inspections.
- There is also a notable shift in the language, embedding the construction regulator and elevating competency requirements.
Note the important addition of Regulation 11F (see p.67 of ADL1:2026) concerning general requirements for competence.