DESNZ (Department for Energy Security and Net Zero) and the BSI (British Standards Institute) have kicked off a project to develop a consensus-based BSI PAS amendment according to the requirements laid down in PAS 0:2022, Principles of PAS standardization and BSI Rules for the structure and drafting of UK standards.

The proposed scope of work is limited to an addition of a new annex around innovation (Annex F) and incorporating ‘Pathways to PAS’.

The project involves the steering group, a review panel and will include a public consultation before publishing the amendments to PAS 2035: 2023 – anticipated September 2025.

SWIGA expect to play an active role in this process of course.
 

What Is PAS 2035:2023 + A1:2025

A PAS is a sponsored fast-track standard that is developed through a consensus-building process facilitated by BSI Standards Limited, according to the requirements laid down in PAS 0:2022, Principles of PAS standardization and BSI Rules for the structure and drafting of UK standards.

A PAS should not be regarded as a BS, EN or ISO standard.
 

PAS 2035:2023

Following a public consultation carried out in early 2023, the British Standards Institution (BSI) published the updated PAS 2035/2030:2023 standards on 28th September 2023.

We are currently coming to the end of the transition period whereby the 2019 standards will be withdrawn on 30th March 2025 and replaced with the new 2023 standards.
 

PAS 2035:2023 + A1:2025 project overview

PAS 2035:2023 is all about retrofitting dwellings for improved energy efficiency and provides the specification and guidance. Obviously it continues to evolve and develop and, as such, DESNZ (Department for Energy Security and Net Zero) and the BSI (British Standards Institute) have announced the 2025 project to review the 2023 guidance along with a draft scope of the PAS Revision which is anticipated to start in April and complete by September 2025.
 

Objectives of the PAS review

This project is to develop a consensus-based BSI PAS amendment according to the requirements laid down in PAS 0:2022, Principles of PAS standardization and BSI Rules for the structure and drafting of UK standards.

The proposed scope of work is limited to an addition of a new annex around innovation (Annex F) and incorporating Pathways to PAS.
 

Draft Scope of the PAS Revision

This PAS specifies requirements for retrofit of dwellings, including:

• assessment of dwellings for retrofit;
• identification and evaluation of improvement options (energy efficiency measures, or EEMs);
• design and specification of EEMs (whether individual measures or packages of multiple
• measures); and
• monitoring and evaluation of retrofit projects.

This PAS covers EEMs that are intended to:

1. improve the insulation of the elements of the building fabric (external walls, roofs, floors windows and doors) and reduce thermal bridging;
2. improve the airtightness of the building envelope;
3. establish a safe dynamic moisture equilibrium through each element of the building fabric;
4. improve the resilience of the building envelope in order to maintain the thermal properties of the building fabric and the capability of the building envelope to manage moisture in a manner suited to its construction;
5. reduce heat loss from ventilation with the use of high efficiency heat exchangers in a fully ducted ventilation system;
6. minimize the risks associated with vapour or other products, for example volatile organic compounds (VOCs), released within buildings subsequent to their airtightness being improved;
7. minimize the risks associated with overheating;
8. provide efficient heating and cooling systems with responsive, intelligent or “smart” controls, including systems that use low or zero carbon (LZC) technologies;
9. provide efficient water heating systems with responsive controls, including systems that use LZC technologies;
10. provide efficient fixed lighting, appliances and equipment with appropriate controls;
11. reduce electricity use and minimize internal heat gains, including systems that use LZC technologies;
12. provide on-site energy storage to improve the usefulness of energy generated by LZC technologies; and
13. reduce the impact of climate change on the building and the occupant.

Alongside the installation of EEMs to achieve some of the intended outcomes above, this PAS also covers the installation of:

• ventilation to achieve good internal air quality and minimize the risk of condensation;
• metering and monitoring systems to promote the efficient use of energy; and
• climate change adaptations needed to improve the resilience of the building to existing and/or future risk from climate change.

In addition to setting out requirements for the commissioning and handover of all of the above, this PAS specifies requirements for advising building occupants about improvement options appropriate to their homes, and the efficient and appropriate use and maintenance of their retrofitted homes, as well as for monitoring and evaluating retrofit projects when appropriate, and feeding back lessons learned to all parts of the supply chain, including the building occupants.

While the PAS 2035 process includes maintenance and repair, works that consist exclusively of maintenance and repair do not necessarily need to follow the full PAS 2035 process. This PAS does not apply to maintenance or repair of any element of an existing dwelling, or system installed in it, which does not involve improvement of the energy performance or ventilation of the dwelling, or a reduction of the carbon dioxide emissions associated with energy use in the dwelling. Nor does this PAS apply to “like for like” replacement of damaged or worn-out elements or systems that do not involve improvement of the energy performance or ventilation of the dwelling, or a reduction of the carbon dioxide emissions associated with energy use in the dwelling. This PAS does, however, apply to the distressed replacement of heating appliances, for which a specific process is outlined throughout.

NOTE Appropriate repair and maintenance of the building fabric can improve energy efficiency and is always the first step in energy efficiency improvements, even though it is not covered in this PAS. Otherwise, an unacceptable level of risk to the future condition of the building might be introduced.
 

Responsibilities of the Review Panel (RP)

The RP is a wide formation of organizations and individuals representing those stakeholder groups that may be affected by the implementation of a PAS, even if only peripherally affected. Consultation with the RP is vital in terms of building consensus in the development of a PAS.

RP members will be invited to submit comments electronically during a public consultation via the BSI Standards Development Portal in April 2025. There are no RP meetings.

Due to the time constraints of the project, comments received after the deadline or in any format other than online via the Portal cannot be considered.
 

Development process

• SG steering group (typically 12 to 15 stakeholders)
• RP review panel (targeted stakeholders, including BSI technical committees)
• SG Review draft is made available to SG only, for technical review
• Public Consultation draft is made publicly available for technical review through BSI’s online draft review system https://standardsdevelopment.bsigroup.com/
• SG Editorial Review draft is made available to SG only, for final editorial review
• SG Meeting Round set of meeting sessions where review comments are resolved by the SG members