PAS 2035
PAS 2035 Framework for Quality Retrofit
PAS 2035 was introduced to establish a consistent, national standard for domestic retrofit delivery, addressing historic quality issues. Developed by BSI and sponsored by BEIS, it sets mandatory requirements for publicly funded schemes, including WHG, ensuring retrofit works are safe, coordinated, and technically robust.
PAS 2035 defines a whole-house approach to retrofit, assessing buildings holistically to improve energy efficiency while protecting occupant comfort, managing risks, and ensuring long-term performance across domestic properties.
Compliance-Led, PAS 2035 Retrofit Delivery
AEG Construction delivers retrofit projects fully aligned with PAS 2030:2023 and PAS 2035, applying a whole-house, risk-based approach that ensures quality, compliance, and lasting performance outcomes.
Safe and appropriate measure selection
Retrofit measures are carefully specified based on property condition, construction type, and occupant needs to prevent unintended consequences and ensure suitability.
Correct sequencing of works
Installations are delivered in the correct order, ensuring fabric improvements support heating systems and renewables for maximum efficiency and performance.
Ventilation and moisture risk management
Ventilation strategies are assessed and implemented to manage condensation, indoor air quality, and moisture risks effectively.
Long-term performance and durability
All measures are designed and installed to deliver lasting energy savings while protecting the building fabric.
Protection for residents and councils
Robust compliance processes protect residents, landlords, and councils through auditable documentation, quality assurance, and regulated delivery.
PAS 2035
How is PAS 2035 different?
This PAS embraces quality retrofit work eliminating problems associated with defects, shallow retrofit, accountability, poor design and performance gap. PAS 2035 delivers a whole building approach to the retrofit process, considering the home, environment, occupancy and the householders' improvement objectives when determining the most suitable measures to install. This eliminates the issue of retrofit work being considered in isolation which can unintentionally damage the overall building performance.
Moreover, five new retrofit roles have also been introduced within the PAS 2035 process, with clear responsibilities and accountabilities established to ensure that individuals deliver quality throughout. Two of the main roles are the Retrofit Assessor and Retrofit Coordinator.
Domestic Retrofit Professionals (PAS 2035)
PAS 2035 sets out clear roles and responsibilities to ensure domestic retrofit projects are planned, managed, and delivered safely, effectively, and in the best interests of homeowners and the wider public.
Retrofit Assessors
Retrofit Assessors are trained to undertake a retrofit assessment for dwellings in accordance with PAS 2035. The assessment provides a detailed understanding of the property and its occupants before any improvement measures are designed.
- Production of an RdSAP assessment
- Creation of a detailed floor plan
- Property condition report
- Occupancy assessment
The data collected from these assessments is used by the Retrofit Coordinator to formulate a Medium-Term Improvement Plan.
Retrofit Coordinators
Retrofit Coordinators are required for all domestic retrofit projects to comply with PAS 2035. They occupy a vital project management role and help protect the interests of both clients and the public.
- Oversee retrofit projects from inception to completion
- Liaise with building owners and project stakeholders
- Ensure effective coordination and compliance
- Manage quality, risk, and project outcomes
Using data from retrofit assessments, a Retrofit Coordinator can prepare a Medium-Term Improvement Plan covering a 20–30 year improvement period.
Building Assessment Process
PAS 2035, the Government’s mandatory standard framework for publicly funded retrofit energy efficiency measures, introduces a risk-based assessment process. An independent Retrofit Coordinator categorises projects into Path A, B, or C depending on the level of risk and complexity.
Path A – Low Risk Projects
Path B – Medium Risk Projects
Path C – High Risk Projects
Path A – Low Risk Projects
Path A represents simple, low-risk measures in standard properties, such as loft insulation.
- Single or low-risk retrofit measures
- Whole dwelling assessment undertaken
- General advice provided independently of installer
- Basic monitoring following installation
Path B – Medium Risk Projects
Path B applies to projects involving multiple or higher-risk measures across several properties.
- Detailed Retrofit Assessment including SAP fuel use
- Construction, occupancy & ventilation appraisal
- Improvement Option Evaluation by Coordinator
- Overheating & traditional buildings considered
Path C – High Risk Projects
Path C is required for complex or high-risk retrofit projects where specialist knowledge is essential.
- Large-scale or multiple high-risk measures
- Conservation areas or special planning approval
- Air permeability testing undertaken
- Structural engineer reports where required