PAS 2035
PAS 2035:2023 Retrofitting dwellings for improved energy efficiency - Specification and guidance is one of a number of Publicly Available Specifications covering retrofit, refurbishment and building upgrades. The others public specifications include; PAS 2030:2023 Installation of energy efficiency measures in existing dwellings and PAS 2038:2021 Retrofitting non-domestic buildings for improved energy efficiency.
PAS 2035:2023 (Incorporating Corrigendum No. 1) Retrofitting dwellings for improved energy efficiency – Specification and guidance describes retrofit building physics, building pathology, thermal models and calculations, approaches to retrofit in the medium term and at scale, performance considerations, standards and constraints, fabric first, interfaces, wholedwelling assessments, distressed replacement, retrofit designs, testing, commissioning and handover. It also also describes the various retrofit related roles, such as the main contractor and retrofit installer, retrofit advisors, coordinators, assessors, and evaluators aswell as standards, frameworks, competency and qualifications relating to these roles.
The PAS document says "Statutory national targets for the reduction of greenhouse gas emissions in response to the threat of climate change imply that very significant improvements need to be made in the energy efficiency of the UK’s building stock, including nearly all its 27 million domestic buildings. The Climate Change Committee sets “carbon budgets” under the Climate Change Act 2008, and the Government’s Net Zero Strategy includes a commitment to improvements in Energy Performance Certificate (EPC) scores in existing dwellings." It goes on to say that it "supports work towards those objectives by promoting and defining technically robust and responsible “wholedwelling” domestic retrofit work, i.e. highquality work that supports:"
- "a) improved functionality, usability and durability of buildings;
- b) improved comfort, health and wellbeing of building occupants and visitors;
- c) improved energy efficiency, leading to reduced fuel use, fuel costs and pollution (especially greenhouse gas emissions associated with energy use);
- d) reduced environmental impacts of buildings;
- e) protection and enhancement of the architectural and cultural heritage as represented by the building stock;
- f) avoidance of unintended consequences related to any of the above;
- g) minimization of the “performance gap” that occurs when reductions in fuel use, fuel cost and carbon dioxide emissions are not as large as intended or predicted; and
- h) protection of the general public and the client in relation to retrofit work."
[edit] Related articles on Designing Buildings
- Alterations to existing buildings.
- Do the building regulations apply to works to existing buildings?
- Demolition.
- Material amendment.
- Material change of use.
- Minor material amendment.
- Non material amendment.
- Change of use class.
- PAS 2038:2021 Retrofitting non-domestic buildings for improved energy efficiency.
- Planning permission.
- Permitted development.
- Principal designer.
- Renovation v refurbishment v retrofit.
- Retrofit.
- Retrofit projects and roles
- Types of work to existing buildings.
Featured articles and news
Mixed reactions to apprenticeship and skills reform 2025
A 'welcome shift' for some and a 'backwards step' for others.
Licensing construction in the UK
As the latest report and proposal to licence builders reaches Parliament.
Building Safety Alliance golden thread guidance
Extensive excel checklist of information with guidance document freely accessible.
Fair Payment Code and other payment initiatives
For fair and late payments, need to work together to add value.
Pre-planning delivery programmes and delay penalties
Proposed for housebuilders in government reform: Speeding Up Build Out.
High street health: converting a building for healthcare uses
The benefits of health centres acting as new anchor sites in the high street.
The Remarkable Pinwill Sisters: from ‘lady woodcarvers’ to professionals. Book review.
Skills gap and investment returns on apprenticeships
ECA welcomes new reports from JTL Training and The Electrotechnical Skills Partnership.
Committee report criticises UK retrofit schemes
CIOB responds to UK’s Energy Security and Net Zero Committee report.
Design and construction industry podcasts
Professional development, practice, the pandemic, platforms and podcasts. Have we missed anything?
C20 Society; Buildings at Risk List 2025
10 more buildings published with updates on the past decade of buildings featured.
Boiler Upgrade Scheme and certifications consultation
Summary of government consultation, closing 11 June 2025.
Deputy editor of AT, Tim Fraser, discusses the newly formed society with its current chair, Chris Halligan MCIAT.
Barratt Lo-E passivhaus standard homes planned enmasse
With an initial 728 Lo-E homes across two sites and many more planned for the future.
Government urged to uphold Warm Homes commitment
ECA and industry bodies write to Government concerning its 13.2 billion Warm Homes manifesto commitment.
From project managers to rising stars, sustainability pioneers and more.
Places of Worship in Britain and Ireland, 1929-1990. Book review.