Approved Document L Volume 1 takes effect in Wales

The 2022 edition of Approved Document L Volume 1 for dwellings takes effect on 23 November 2022 for use in Wales, according to the Welsh Government document itself¹. The approved document gives guidance for compliance with the Building Regulations for building work carried out in Wales, and applies to dwellings only¹. It supports Part L of Schedule 1 to the Building Regulations 2010¹.

The document does not apply to work on a particular building where a building notice, full plans application or initial notice were submitted before that date, provided the work for each building is started before 23 November 2023¹. It also does not apply to sites where a building notice, initial notice or full plans application were submitted before 31 July 2014 and building work commenced before 31 July 2015¹. The document states that there have been no changes to Part L of Schedule 1 to the Building Regulations¹.

For new dwellings, the approved methodology is the Standard Assessment Procedure, and calculations must use version 10 of the UK Government's Standard Assessment Procedure for energy rating of dwellings¹. The Minimum Energy Efficiency Rating can be met by achieving a minimum SAP rating of 81¹. A newly constructed dwelling must be shown to meet regulations 26, 26A, 26B and 26C by producing calculations demonstrating compliance with the Target Emission Rate, in kgCO2e/m2/year, and the Target Primary Energy Rate, in kWhPE/m2/year¹. Where a building is erected, it must be a nearly zero-energy building¹.

The 2022 edition incorporates 2024 amendments, described in the document as various corrections, with reference to Circular Letter WGC 006/2024¹. The document carries the reference WG49936 and digital ISBN 978-1-83625-042-5¹.

Separately, guidance published by BEAMA, the UK trade association for manufacturers and providers of energy infrastructure technologies and systems, states that the 2022 edition of Approved Document L Volume 1 for Wales relates to work carried out from 23 November 2022². BEAMA states that the Domestic Building Services Compliance Guide is no longer applicable, with all guidance and minimum standards now incorporated into Approved Document L, Volume 1: Dwellings². Its guidance sets out minimum boiler efficiencies: gas boilers have a minimum efficiency of 92% as defined by ErP, and oil boilers have a minimum efficiency of 91%, or 86% if a combi boiler². It states that full heating systems installed in a new or existing dwelling should be sized to operate at a maximum flow temperature of 55oC, and that when a boiler is replaced in an existing dwelling, each room should now be provided with thermostatic room controls².

"This approved document takes effect on 23 November 2022 for use in Wales."

It states that for domestic properties the previous 2014 guidance applies only to individual units where plans were submitted by 23 November 2022 and work on the unit commenced by 23 November 2023³. Kingspan gives maximum U-values for new elements in domestic work under ADL1 2022, including 0.13 W/m2K for a flat roof, 0.18 W/m2K for a wall and 0.15 W/m2K for a floor³. For renovated elements it gives limiting U-values for retained fabric of 0.35 W/m2K for roofs and 0.70 W/m2K for walls and floors, with maximum area weighted averages for domestic work of 0.16 W/m2K for roofs, 0.55 W/m2K for cavity wall insulation, 0.30 W/m2K for internal or external wall insulation and 0.25 W/m2K for floors³. It states that where improved values are not technically feasible or will not provide payback within 15 years, the best achievable U-values should be sought³.

Why it matters for households

The document governs the energy performance standard that new and altered dwellings in Wales are assessed against. For a household, the practical effect sits in the fabric and the services: how much heat a home loses through its walls, roof, floor, windows and doors, and how efficiently the heating system converts fuel into heat. The Welsh building regulations for insulation and glazing set the U-values that elements are expected to meet, and the Part L requirements for insulation and glazing explain how those figures are applied. Because the 2022 edition applies in Wales and not England, the standards differ either side of the border, as set out in building regulations in Wales and building regulations in England. The wider split of powers is covered in energy and buildings policy in Wales.

For an existing home, the requirements bite mainly when work is done: extensions, replacement windows and doors, replacement or renovation of thermal elements, and boiler or cylinder replacements. The BEAMA guidance indicates that a boiler replacement in an existing dwelling now brings a requirement for thermostatic room controls in each room, with limited exceptions, and that gravity-fed systems should be upgraded to fully pumped². It also notes that for a radiator replacement the requirement for thermostatic controls in each room should only be considered good practice, and that where a hot water cylinder replacement is designated as an emergency, boiler interlock and a separate timed hot water circuit can be considered good practice only². A cylinder thermostat should always be fitted with a replacement cylinder². These are the points at which a household's control over its own energy use, and its exposure to running costs, is most directly shaped.

What happens next

The transitional arrangements in the approved document allow work on a building to proceed under the previous guidance where a building notice, full plans application or initial notice were submitted before 23 November 2022, provided the work for each building is started before 23 November 2023¹. Kingspan states that the 2014 domestic guidance was superseded on 23 November 2023³. The document records that the 2022 edition incorporates 2024 amendments, described as corrections, with details in Circular Letter WGC 006/2024¹. No further dated steps are given in the material.

Sources3 cited

1. Approved Document L Vol 1 Dwellings - Conservation of fuel and power, gov.wales
2. Part-L-2022-Heating-Controls-Guidance.pdf, beama.org.uk
3. Approved Document L - Wales | Kingspan GB, insulation.kingspan.com