School of Architecture

  • Code Level 5 Homes in Swindon - Phase 1

    Post completion and early occupation building performance evaluation

    Closing the gap between design aspiration and as-built performance in a Code level 5 housing development in the UK.

    The study aims to broaden our understanding on the energy performance of low-carbon homes and close the feedback loop between design aspiration and post-construction performance.

    The study will focus on three basic objectives:

    • Capture the ‘as build’ performance of the building envelope and installed equipment and compare it to the ‘as designed’ one.
    • Evaluate the success of the handover process providing a learning legacy for future projects.
    • Map the reaction of the occupants as they first settle in their new houses (amenity, comfort levels, understanding of the new systems).

    • Process

      To identify any deviation from the design intent and map the initial occupants’ reactions, the BPE study was organised in two key stages covering the Design and construction phase as well as the Post-construction and early occupancy phase of the new homes.

      • During the Design phase a detailed design and construction audit took place including a SAP calculation review, drawings and specifications review, semi-structured interviews with the design team, walkthroughs with the client and developer, observation and review of control interfaces.
      • The Post-Construction and early occupation phase consisted of a whole house fabric test (Co-heating, Air-permeability, In-situ U-value, thermographic survey), a review of the commissioning processes, observation of the handover process and occupancy evaluation using BUS questionnaires, walkthroughs and interviews with the occupants.


      The difference between design aspiration and as-built performance was highlighted by most of the study elements and the findings were found to be correlated to each other and passed through the different construction phases. The main findings were mostly related to the difficulty of the contractors to engage with new materials and technologies, complications in the communication between the different project parties, lack of proper system commissioning and inadequacy of the induction process.

      It is vital that these evidence-based lessons on the as built performance of new low carbon housing are taken on board on an iterative basis and embedded into knowledge management systems of councils, developers, house builders, designers and equipment suppliers.

      Project team

      Project details

      Duration: 2011

      Funded by:
      Technology Strategy Board

      Project Partners:
      NPS Group
      Swindon Borough Council
      Institute for Sustainability (IfS)

      Total project value: £88,692
      Income to OBU: £64,330


      • Gupta, R. and Chandiwala, S. (2009). Achieving low carbon buildings using Code for Sustainable Homes in the UK. International Journal of Low-Carbon Technologies (4), pp.187-196 DOI: 10.1093/ijlct/ctp018
      • Final report: Post-construction stage and early occupancy, August 2011