British Standard BS 40101 Building performance evaluation of occupied and operational buildings

BS 40101 is now published

Available from the BSI shop. Free to BPN Members.

LAUNCH EVENT 14/02/22: see below for recordings of the event, including presentations from co-authors Dr Kerry Mashford OBE and Dr Zack Gill, and the Q&A session.


Growing interest in BPE

In recent years there has been growing interest in measuring the performance of how buildings work, including the energy efficiency, properties of the fabric, construction and installed services, the quality of the indoor environment and influence on human experience, factors affecting health, wellbeing, and productivity. In particular, there has been an appreciation of the performance gap – the difference between the design intentions and the resulting physical reality.

Meanwhile, there have been significant advances in monitoring technology and a lowering of costs associated with these, leading to increased uptake of the practice of building performance evaluation. The BPN, amongst others, identified the need for a British Standard that could support this increasingly common activity and help make it routine, as well as robust and useful.

Purpose of a British Standard for in-use BPE

The purpose of this British Standard is, therefore, to:

  1. enable consistency in the evaluation of the performance of buildings and the reporting and recording of evaluation findings and conclusions;
  2. provide a basis for verification of specified performance in new and upgraded buildings in respect of key performance parameters and attributes (e.g. for “pay as you save” finance, performance contracting, performance-linked finance, and potentially for future regulatory compliance);
  3. provide a basis for determining whether the performance specification of a new or upgraded building is achieved in use; and
  4. provide a basis for the identification of improvement options or corrective actions (ranging from setting adjustments to extensive fabric upgrade) and the development of improvement strategies, process improvements, plans and specifications (e.g. in pursuit of transition to net zero carbon).

Scope of BS 40101

The scope of BS 40101 covers

  • the planning of the BPE studies,
  • choose of comparators (such as regulatory requirements, design predictions, models, industry benchmarks, past records for the same building).
  • data to be gathered so that it is relevant to the level of evaluation pursued.
  • data naming and storage.

Thanks to UKRI and Industrial Strategy Challenge for funding this work.

Thanks for their very hard work to authors Dr Kerry Mashford OBE and Dr Zack Gill, and co-chair Prof Fionn Stevenson.


On 14th February 2022, we held a launch event online with co-authors Dr Kerry Mashford OBE and Dr Zack Gill. Here we have slides from our Chair, George Martin, and Kerry and Zack. Then, recordings of the co-authors’ presentation and the Q&A follow.


BPN introduction slides

BS 40101 coauthor slides

Presentation by co-authors Dr Kerry Mashford OBE and Dr Zack Gill