PAS 2035 – What is it and what does it mean for you?

In May 2019, the British Standards Institute (BSI) published a document called BSI Publicly Available Specification (PAS) 2035. You will not have heard about this on the national news. However, if you work in the energy efficiency sector, it will have a huge impact upon you, your clients and suppliers. The purpose of the document is to create a framework for deep retrofit projects that are high quality, safe and fit for the future. It is a long-overdue response to the Each Home Counts Review (2015-2017). This article clarifies the impacts and timescales of PAS 2035 and should get you thinking about how to prepare for what should be the most radical shake-up of the energy efficiency industry in a generation.

The government department responsible for the Energy Company Obligation (ECO), the Department for Business, Energy and Industrial Strategy (BEIS), took the view that until these issues were resolved, large-scale retrofit was not viable. The industry would not reform itself, and therefore new, mandatory working practices would have to be introduced. Consequently, BEIS sponsored BSI to create new guidance for the sector and Working Groups were formed to shape it. Dr Peter Rickaby, a long-standing retrofit expert, was appointed to head this up as Technical Author. Working Groups comprised of professional, membership training and certification bodies, a broad range of expert consultants, architects and other individuals.

What is PAS 2035?

Contrary to popular belief, PAS 2035 is not a new BSI Standard – it is a framework for project delivery. It addresses the fundamental structural problems that blight many energy efficiency projects, no matter how well-intentioned the participants may be. Problems such as:


10% of all solid wall insulation projects resulted in a Type-1 Fail (Ofgem 2013).

Unintended Consequences

Health and social problems made worse by retrofit, not better.

Shallow Retrofit

Availability of funding resulting in the installation of single-measures at the wrong time and place.


Rules of the game meaning the buck is continually passed on, resulting in litigation.

Poor Design

Low profit margins exclude building professionals from engagement in retrofit.

Performance Gap

Predicted energy savings not delivered in practice.


Blog post courtesy of retrobookacademy


PAS 2035

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