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The UK needs to improve the energy efficiency of its non-domestic building stock very significantly if we’re to achieve net zero by 2050, as legally mandated by the Climate Change Act. This blog post discusses a new PAS produced to support the construction and buildings management sectors with that task.

The UK’s Climate Change Act, as amended in 2019, sets out the statutory objective of achieving net zero greenhouse gas emissions by 2050. This will require the reduction of not just carbon dioxide emissions, but all greenhouse gas emissions associated with energy use in buildings to the lowest possible level, in the context of a net zero balance between energy supply and demand.

Yet according to the UK’s Climate Change Committee (CCC) – an independent statutory body set up to advise the UK and devolved governments on emissions targets – reducing emissions from existing UK buildings will be one of the biggest challenges in the net zero transition. Estimates show that non-domestic buildings in the UK account for 17% of our energy consumption and 12% of greenhouse gas emissions , and there are nearly two million non-domestic buildings that need to be improved.

With this in mind, the Department for Business, Energy, and Industrial Strategy (BEIS) sponsored BSI to quickly produce a document that would help anyone involved in the effort to improve the energy efficiency of existing non-domestic buildings. A steering group comprising more than 20 members was assembled, representing academia, trade associations, government agencies, professional institutions, accreditation bodies, and regulatory bodies. The result of their work is: Retrofitting non-domestic buildings for improved energy efficiency – Specification.

Energy efficiency measures

specifies requirements for retrofitting non-domestic buildings for improved energy efficiency. It covers all buildings except those used as private dwellings (i.e. houses, bungalows, flats, or apartments) including multi-residential buildings in which occupants share some communal facilities, e.g. hotels, guest houses, hostels, and students’ and nurses’ accommodation.

The PAS aims to be comprehensive. Its requirements cover the assessment of building for retrofit of energy efficiency and related measures; the identification and evaluation of improvement options (energy efficiency measures); and management of the retrofit process from inception to completion.

The PAS details requirements for preparing medium-term improvement plans and covers the design and specification of energy efficiency measures, whether they are individual measures or packages of multiple measures. It also deals with the installation of measures; their testing, commissioning, and handover; the fine-tuning of the performance of retrofitted buildings, and finally the evaluation of retrofit projects.

Incidentally, this new PAS is also complementary to , Retrofitting dwellings for improved energy efficiency. Specification and guidance which covers how to assess domestic buildings for retrofit and also covers the installation, commissioning and handover of retrofit projects.

Multiple benefits

was written to be used by anyone who’s involved in the funding, assessment, specification, design, or installation of improvement measures. This will include building professionals, architects, facilities managers, engineers, surveyors, and construction professionals, including managers and site managers, architectural technologists, and suppliers of building materials and products. The document will also be of interest to owners, developers, insurers, investors, tenants and landlord bodies, local authorities, building control bodies, energy assessors, and auditors.

The PAS will be invaluable because it promotes and defines technically robust and responsible “whole-building” retrofit processes that will deliver multiple benefits. These include the improved functionality, usability, and durability of buildings that will be more comfortable and will promote greater well-being, health and safety (including fire safety), and productivity.

Meeting the PAS’s requirements will also enable buildings to use low- or zero-carbon energy supplies, and of course improve their energy efficiency, leading to reduced fuel use, fuel costs, and pollution as well as a reduced environmental impacts of buildings. Its use will also minimize the “performance gap” that occurs when reductions in fuel use, fuel cost, and carbon dioxide emissions are not as large as intended or predicted.

Use of the PAS will also contribute to the protection and enhancement of the architectural and cultural heritage of our building stock and ensure that retrofitters avoid unintended consequences related to any of the above.