Retrofit for the Future - Warwall Street, London

Principal Investigator(s): Professor Rajat Gupta


Project start: September 2009

Project finish: December 2013

Funded by: Innovate UK

About us

Improvement to typical 1990s mid-terrace house

Transformational changes have been made to the house to bring about highly efficient energy use, and improve the quality of living for residents. These qualitative improvements are rooted in an understanding of the real concerns, habits and aspirations for tenants in social housing, elicited from a survey and evaluation of occupancy prior to design.

61 Warwall is a mid-terrace, two-storey, three-bedroom house located on the Windsor Park Estate, London Docklands. The house was originally built in 1992, with masonry cavity walls, double glazing and a pitched roof with loft insulation. It was retrofitted by Penoyre and Prasad under the Technology Strategy Boards Retrofit for Future programme to meet the target of an 80% reduction in carbon emissions from 1990 standards. 61 Warwall is being monitored for two years to evaluate performance, quality of construction and effectiveness of the retrofitted measures. The findings will create a deeper understanding of the factors influencing household energy consumption and the suitability of individual measures for large scale retrofit.

Evaluation of domestic buildings is intended to determine the:

  • performance of the building in reality
  • performance of key energy using (and generating) equipment and systems
  • amenity, comfort, control and convenience experienced by occupants.

Thermal images of the house


Rajat Gupta

Professor Rajat Gupta

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

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The presence of a long-term tenant enabled us to investigate current living habits and energy use before making any changes. The key retrofit changes included:

  • an innovative ‘breathing’ roof with wood fibre slab and hemp fibre quilt insulation
  • vacuum insulation panels over the solid floor
  • triple-glazed windows with operable ventilation panels and security louvers
  • a new light well within the existing loft space brings light and air into the otherwise dark centre, inducing stack ventilation and allowing clothes to be dried here, instead of energy-intensive tumble-drying.

A key challenge for successful delivery of the project was the continued occupancy of the residents throughout the retrofit. Handover and initial testing are over, and an innovative energy and space conditions monitoring suite has been installed which feeds live data back to a repository. This will be reviewed against predicted targets and can be adjusted to further reduce wasted energy. This monitoring can provide a detailed breakdown of renewable energy generated, delivered and wasted allowing for a full analysis. The predicted CO2 emissions after retrofit are 16kg/m2/yr - a reduction of 79% from the 1990 baseline for average UK social housing.

In 2011, the project won the ‘Best small housing project' category at the 3R Awards - a scheme celebrating the most innovative and effective retrofits launched by the Architects' Journal, Construction News and New Civil Engineer.

Thermal imaging of lounge space

Project details

Funded by:

  • Technology Strategy Board (now Innovate UK)

Project partners:

  • Penoyre & Prasad Architects
  • XCO2 Energy
  • Lakehouse Contracts Ltd.
  • Osborne Edwards


  • East Thames Group

Pictures of 61 Warwall Street


Research reports

  • Handover Review, July 2011
  • Home user guide evaluation, Post-retrofit completion and monitoring report, November 2011
  • Post-retrofit completion and monitoring reports (Quarterly)

Blogs and diaries

  • Retrofit for future diaries, July 2011