PAS 2035:2023: The updates and implications

The Publicly Available Specification (PAS) 2035 provides requirements and guidance for retrofit energy efficiency measures (EEMs) in existing UK homes. It works in conjunction with PAS 2030, which covers the physical installation and handing over retrofit measures to the homeowner or client.

PAS 2035 was updated in September 2023 to reflect evolving best practices, address implementation feedback, and align with the UK’s net zero emissions goals. Here we look at the main updates to be aware of and the implications.

Image: PAS2035:2023 The updates and implications text over green background

Key changes in PAS 2035:2023

The latest version of PAS 2035 was released in September 2023, introducing a few notable changes:

  • More emphasis has been placed on whole-dwelling retrofit rather than the installation of measures in isolation. The standard now references appointing a “Main Contractor” to oversee the project.
  • The retrofit design process can commence earlier in large-scale programmes based on an assessment of archetypes or dwelling types before every home is surveyed.
  • The requirements for providing retrofit advice to occupants before, during and after the works have been strengthened.
  • The guidance around ventilation has been updated following revisions to building regulations.
  • Risk assessment requirements have been simplified to avoid unnecessary complexity.
  • More focus has been placed on monitoring retrofit outcomes and feedback to improve quality.
  • New allowances have been put in place for for “distressed installations” such as urgent boiler replacements.
  • The consideration of climate resilience, flood risk and overheating has been enhanced.

Implications of the changes

Whilst at VOR we have always worked to the highest standards, we welcome these revisions iin PAS 2035: 2023 as they will have positive implications to the industry as a whole:  

  • The emphasis on whole-dwelling retrofit should improve quality and prevent unintended consequences from measures installed in isolation.
  • Allowing retrofit design to start earlier in large programmes will increase efficiency.
  • More advice for the occupants of the houses undergoing Retrofit should maximise energy savings and performance.
  • Climate resilience is now higher on the agenda.
  • Monitoring outcomes and feedback will help drive up standards.
  • Distressed installations can now be retrospectively PAS 2035 compliant, allowing urgent work to be carried out more quickly.

Overall, the changes represent an evolution that makes PAS 2035 more flexible and aligned with large-scale retrofit projects while still maintaining rigorous standards.