PAS 2035 is a comprehensive standard initially introduced in 2019 and updated in 2023 as part of the UK government’s commitment to improving energy efficiency in buildings. Energy-efficient dwellings require less energy to heat, resulting in lower energy bills and carbon dioxide emissions, helping to meet the UK’s energy efficiency goals in its bid to meet net zero by 2050.
In this guide, we’ll cover some important information on PAS 2035, including what PAS 2035 is, what’s involved in a retrofit, who’s responsible for delivering PAS 2035, and more.
What Is PAS 2035?
In short, PAS 2035 is a framework to follow for the retrofitting of dwellings to improve energy efficiency. It details the best practices and guidance for domestic retrofit projects, delivering a ‘whole house’ or ‘whole building’ approach that ensures the delivery of the desired energy savings without compromising on quality or safety.
By adopting a whole building approach, it addresses potential issues, from moisture control to insulation, in a comprehensive manner. In turn, this framework helps to ensure consistency and quality across retrofit projects.
What is PAS 2035 Retrofit and What’s Involved?
PAS 2035 retrofit involves a comprehensive assessment of a building, which is followed by the design and implementation of energy-efficient measures. This involves assessing the building’s condition, identifying retrofit measures, and making sure they’re installed correctly.
Retrofit measures include installing:
- Double or triple glazed windows.
- Wall, floor and loft insulation.
- Efficient and renewable heating systems.
- Draughtproofing.
- Solar photovoltaics for the generation of renewable electricity.
Is PAS 2035 Mandatory?
While PAS 2035 is not mandatory for every retrofit, PAS 2035 compliance is a requirement for some government-funded retrofit projects. That said, although it’s not needed for non-funded projects, it’s recommended that the framework be followed for any residential projects.
This comes down to the fact that it offers a foundation for compliance and best practice for the assessment, design, installation and monitoring of energy-efficient measures.
The adoption of PAS 2035:2023 is essential to mention here, as from the beginning of last month, it has become mandatory for nearly all government-funded schemes to adopt PAS 2025:2023. As such, retrofit professionals must now transition to the new standard.
You can download the document to learn more about the changes PAS 2035:2023 has brought here.
Who Is Responsible For Delivering PAS 2035?
The delivery of a successful retrofit depends on a number of roles, including:
- Retrofit assessor
- Retrofit coordinator
- Retrofit designer
- Retrofit installer
- Retrofit evaluator
Retrofit Assessor
The Retrofit Assessor’s responsibility is to carry out an energy assessment of the dwelling in question. This involves collecting data on the dwelling’s structure, heating systems and controls and any existing efficiency measures and a condition survey and occupancy assessment.
The Retrofit Assessor then passes this information to the Retrofit Coordinator.
Retrofit Coordinator
The role of the Retrofit Coordinator is to draw up the improvement plan with the information provided by the Retrofit Assessor. The Retrofit Coordinator is considered the primary role, as they have full oversight of the installation and handover stages, working closely with the Retrofit Installer to ensure all elements of the retrofit are properly managed.
Under PAS 2035:2023, their role spans from project inception to completion, and their responsibilities have expanded, particularly when it comes to the documentation of non-compliance as well as site visits.
Retrofit Designer
The Retrofit Designer develops the assessment and the retrofit strategy to provide a compliant retrofit design.
If working on a traditional or protected building, unless you are a conservation-accredited Retrofit Designer, a mandatory requirement for being involved in a Government or energy provider (ECO) funded retrofit is to hold a Level 3 Award in Energy Efficiency for Older and Traditional Buildings (QCF) qualification.
Retrofit Evaluator
The Retrofit Evaluator is responsible for carrying out monitoring and evaluations of the effectiveness of a project following the retrofit. This often involves data gathering or can be a detailed analysis of data using several control monitors and intrusive survey work.
The Environment Study Centre offers a range of retrofit courses, including a Level 3 Award in Energy Efficiency for Older and Traditional Buildings course, which it developed over 10 years ago. Discover more about our retrofit courses here.
What’s the Difference Between Pas 2030 & Pas 2035?
PAS 2030 and PAS 2035 are both UK retrofit standards, but they serve distinct roles. PAS 2030:2023 focuses on how energy-efficiency measures are installed: it sets out requirements for installers, materials, training, and safe, quality workmanship. By contrast, PAS 2035:2023 takes a whole-house view covering initial assessment and design, through risk management, occupant engagement, and post-installation evaluation.
The 2023 update also introduces a requirement for a “medium-term improvement plan,” tighter oversight, and makes adherence essential for government-funded retrofit work. As one guide notes, while PAS 2035 shapes what retrofit measures should be and how they’re planned, PAS 2030 ensures those measures are installed correctly and safely.
We hope that this guide on PAS 2035 has helped you gain a better understanding of PAS 2035.
How We Can Help
If you’re looking to take a retrofit course, look no further than the Environment Study Centre’s Level 3 Award in Energy Efficiency for Older and Traditional Buildings – 2 Day Retrofit Course.
This course features both BSI PAS 2035 and PAS 2038, with examples of their use on traditional buildings and is delivered by a co-author of these standards, Professor John Edwards, who is also the lead author of BS7913 – the British Standard for work to traditional and historic buildings.
As a trusted leader in retrofit education, the Environment Study Centre can support you with several courses on building retrofit. Get in touch with our team today to find out more about our retrofit courses.
