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What is PAS 2035?

PAS 2035 is the latest publicly available specification for low-energy domestic retrofit from the British Standards Institution (BSI).

What is PAS 2035

By Anthony O'Neill, Nuaire Residential Sales Engineer, March 2022

It provides specification for the energy retrofit of domestic buildings and details best practice guidance for domestic retrofit projects. The framework came into effect from June 2019 following the recommendations of the Each Home Counts review, which was designed to determine better processes for the retrofit of both energy-efficient and renewable energy measures.

It specifies requirements involving:

  • The assessment of dwellings for retrofit improvements (such as ventilation, heating, and hot water)
  • The identification and evaluation of improvement options (Energy Efficiency Measures or EEMs)
  • The design and specification of EEMs (whether individual measures or packages of multiple measures)
  • The monitoring and evaluation of retrofit projects
  • The installation, commissioning, and handover process
  • The insulation of building fabric elements and air tightness
  • The provision of efficient heating and cooling systems with smart controls, including systems using low or zero carbon (LZC) technologies.

PAS 2035 has also been sponsored by the UK Government's Department for Business, Energy, and Industrial Strategy (BEIS)

How is PAS 2035 different?

PAS 2035 delivers whole-home quality retrofit work to eliminate problems associated with defects, shallow retrofit, and poor design. By considering the entirety of the property along with the environment and tenant lifestyles, no one improvement is made in isolation which can unintentionally damage the overall building performance.

This PAS covers such work as:

  • Retrofit programmes promoted and/or funded by national or local government schemes e.g. the Energy Company Obligation (ECO)
  • Retrofit programmes initiated and/or funded by landlords, including social housing organizations, private landlords in the domestic sector and commercial property portfolio holders
  • Retrofit of individual buildings by their owners and/or occupants, including both domestic and commercial owner-occupiers
  • Retrofit that is integrated with and forms part of broader repairs, maintenance and improvement (RMI) activity related to individual buildings or building stocks

Furthermore, five new retrofit roles have also been introduced with clear responsibilities and accountabilities established to ensure that individuals deliver quality throughout.

PAS 2035 specifies the retrofit roles as follows:

  • Retrofit Advisor
  • Retrofit Assessor
  • Retrofit Coordinator
  • Retrofit Designer
  • Retrofit Evaluator

Further information on these roles can be found HERE

PAS 2035 and TrustMark

The TrustMark has been established as the new quality mark within the retrofit standards framework. It is supported by an Industry Code of Conduct, a Consumer Charter, and a framework of technical standards for retrofit.

Those who hold the TrustMark are qualified under an operating framework and can demonstrate to consumers that they have the skills and knowledge to deliver the best practice standards and trading practices in the sector.

PAS 2035 and Nuaire

Good ventilation is critically important to the health of the property and its inhabitants as air flow through a building minimises the build-up of indoor air pollutions such as condensation dampness, mould, volatile organic compounds (VOC), radon, and carbon monoxide.

Under PAS 2035, existing ventilation shall be assessed as inadequate for the improved dwelling if one or more of the following are apparent:

  • There is evidence of condensation and/or mould growth in the dwelling
  • There is no ventilation system, or the ventilation system is incomplete or not functional
  • There are not undercuts of at least 600mm2 beneath all internal doors, above the floor finish, to allow air to move through the dwelling
  • There is no provision for purge ventilation of each habitable room (e.g. by opening windows)

To help mitigate these risks and ensure healthy living environments for years to come, Nuaire offers a range of BBA certified product solutions.


BBA Certified Product Solutions

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