Code Level 4 Homes in London - Phase 2


Project start: September 2012

Project finish: September 2014

Funded by: Innovate UK

About us

Category: Domestic-in use building performance evaluation.

Objective: Understanding the effects of design and handover process in the in-use performance of a low carbon affordable housing.

The social housing development is split into two separate sites in Hanworth (Hounslow) comprising of 10 two-storey houses, owned by the Thames Valley Housing Association (TVHA) and built on previously brownfield sites, all achieving Code for Sustainable Homes Level 4. The evaluation focused on two houses, one 3-bed mid-terrace on Pippin Close and the other 5-bed detached house on Barnlea Close.

The in-use study over two heating seasons aimed reveal the gap between design intent and actual in-use performance with particular focus on:

  • what the overall energy performance of these house types in occupancy is and the effect of user behaviour on building performance
  • the energy use of the houses for space heating, water heating, ventilation, water use (proportions of mains and rain water), lighting, cooking, cooling and appliance use; how the occupants think and feel about living in these houses
  • ease of use of controls and layout; impact of space flexibility; how the houses perform in relation to external weather conditions in terms of heating and cooling
  • and finally, suggesting adjustments and monitoring the impact of these.


Rajat Gupta

Professor Rajat Gupta

Professor of Sustainable Architecture and Climate Change, Director of OISD and LCB Group

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  • The study included elements such as design and construction audit, drawings and SAP calculation review, qualitative semi-structured interviews and walkthroughs with occupants and design team, photographic survey so as to compare design intentions with final performance.
  • Gas and electricity consumption were monitored and compared with SAP predictions.
  • The efficiency of the Solar PV was logged and analysed. Energy consumption patterns documented using DomEARM. The two case study houses were also tested for air permeability at the beginning and end of the two year study.
  • BUS questionnaire surveys (summer, winter) and a TM22 audit were carried out with all occupants.


The results were designed to inform current and future developments by TVCHA which has over 14,500 properties under management in south-east England and aims to construct around 400 Code Level 4 units within the 3 years following this project. The results help to determine whether the residents are achieving the maximum benefit from their new homes. The data gathered will be essential in selecting future construction methods.

Project details

Funded by:

  • Innovate UK (formally known as Technology Strategy Board)

Project Partners:

  • Thames Valley Housing (TVCHA)
  • BPTW Partnership
  • Hill Partnership


  • Total project value: £59,992
  • Income to OBU: £43,918


  • Gupta, R., Kapsali, M and Howard, A. (2018) Evaluating the influence of building fabric, services and occupant related factors on the actual performance of low energy social housing dwellings in UK, Energy and Buildings, 174, 548-562
  • Gupta, R., and Kapsali, M. (2015): Empirical assessment of indoor air quality and overheating in low-carbon social housing dwellings in England, UK, Advances in Building Energy Research, 10:1, 46-68
  • Gupta, R. and Kapsali, M. (2014). How effective are ‘close to zero’ carbon new dwellings in reducing actual energy demand: Insights from the UK, Proceedings of the 30th International PLEA Conference, 16-18 December 2014, Ahmedabad, INDIA
  • Gupta, R. and Kapsali, M. (2014) Evaluating the effect of occupant behaviour and expectations on actual energy use and environmental conditions in ‘sustainable’ social housing in South East England, 8th International Windsor Conference, 10-13 April 2014, Windsor, UK