W2UP4 -Occupant Evaluation and Energy Performance Analysis of Barbican Estate Dwellings
23rd October 2015 Carrie Behar

Occupant Evaluation and Energy Performance Analysis of Barbican Estate Dwellings

Carrie Behar, UCL


A post-occupancy evaluation of 2056 residential dwellings was carried out at the Grade II Listed Barbican Centre in London. The purpose of the study was threefold: Firstly, the work sought to characterize baseline user satisfaction, energy-use and behaviour in Barbican dwellings. The second aim of the study was to investigate options for refurbishment strategies to reduce energy consumption without compromising the heritage value of the buildings, which are architecturally significant and retain many original features such as the centrally controlled electric district heating system. Thirdly, the project considered how effective the adopted combination of post-occupancy evaluation techniques has been at identifying problem areas and enabling the development of workable solutions at a case study site.

Carrie Behar talks about this project:


This project takes place in a time of great change. It is now widely accepted that anthropogenic climate change is one of the greateast threats faced by society today, and, that in order to mitigate against the potentially disastrous effects of climate change, we need to take action to drastically reduce our CO2 emissions accross all sectors. For example, existing buildings will need to reduce their CO2 emissions by 34% by 2020 and 80% by 2050 through a combination of energy efficiency and low carbon energy supply technologies.

Flats account for approximately 20% of the UK household stock with a significant proportion of these being purpose built. Heritage laws limit the scope of refurbishment that might otherwise take place to increase energy efficiency; the Barbican Estate is currently a Grade II listed building Occupant behaviour is a significant factor in increasing energy efficiency, although their behaviour is affected by perceptions over such things as control, accessibility and understanding of energy supply systems.


The Barbican occupies a 25 hectare site in the heart of London. It was constructed during the 1960’s and 1970’s, and in 2001 the Barbican Centre was awarded Grade II listing, as a set of buildings and landscaping building of ‘specific architectural interest’. As well as cultural attractions, the Barbican comprises over 2000 flats, contained in terraces, towers and apartment blocks across 21 buildings. Around 4000 people currently live at the Barbican.

The primary construction material used at the Barbican is concrete, made using Pen Lee crushed granite. In terms of environmental performance, the solid concrete walls are good transmitters of both heat and sound. The Barbican was built at a time when energy was cheap; consequently, there is virtually no insulation, except beneath the heating elements buried in the ground floors. Thermal bridging, that is, weak points in the building’s thermal envelope which enable heat to flow through areas of effective heat transmission, are prevalent throughout.



The research took the form of a residents survey, and an evaluation of metered heating energy consumption data. A questionnaire was developed based on the domestic BUS methodology, as well as a set of questions about domestic energy use behaviours. Questions were tailored to make them more relevant to the Barbican residents, and additional questions were added after consultation with representatives of the residents’ sustainability group. Both qualitative and quantitative data were collected and analysed using a variety of statistical and qualitative methods.


Results show that overall levels of satisfaction at the Barbican are high, with comfort, satisfaction and forgiveness indices scoring well above BUS benchmarks (99th, 99th and 89th percentiles respectively). The main areas of dissatisfaction include lack of heating and noise control, perceived dry air throughout the year and variable internal temperatures during winter. Sub analysis of the blocks revealed that residents in the towers are significantly more satisfied than other residents with ‘space’, ‘storage’ and ‘needs’ variables (p=0.000003, p= 0.0003 and p= 0.0002 respectively). 89% of residents were found to use windows to control the heating during winter. This has serious implications for the estate’s energy consumption, as well as the cost of heating to all residents. It was also found that people who use trimmers to adjust the heating, by altering the electric charge entering each flat, are significantly less likely to open windows to control heating during winter (p=0.04).


Recommendations are made for a programme to spread awareness about how the trimmers can be used among the residents. Suggestions are made for a systematic appraisal and adjustment of trimmers across the site to improve energy efficiency and reduce the cost of heating to residents.

The work also offered a critique of the appropriateness of using this combination of POE techniques as a pre-intervention diagnostic tool, and concluded that although the chosen methods were successful in identifying a workable solution to some of the residents’ concerns, there is an opportunity for a more targeted methodology to be developed.


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Project Team

Carrie Behar
Ian Hamilton


Conference poster

An Investigation of the Effectiveness of PostOccupancy Evaluation Techniques in Characterizing Baseline User Satisfaction, Energy Use and Behaviour in Barbican Centre Dwellings

Presentation poster based on findings of my MRes dissertation of the same name, shown at the LoLo Annual Colloquium 2011


An Investigation of the Effectiveness of Post-Occupancy Evaluation Techniques in Characterizing Baseline User Satisfaction, Energy Use and Behaviour in Barbican Centre Dwellings

Dissertation completed as part of MRes EDS Course

Journal paper (first author)

Utilising resident feedback to inform energy-saving interventions at the Barbican

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The introduction of the Green Deal provides evidence of the UK Government’s commitment to improving the energy efficiency of our ageing and underperforming housing stock. However, the issue of what to do with those buildings which for reasons of historical or architectural significance do not lend themselves to conventional fabric interventions has not been addressed fully. A residents’ survey was conducted at the Grade II listed Barbican Centre in London, to characterise levels of occupant comfort and satisfaction, to identify any problems experienced by the residents, and to explore possibilities to improve the energy performance of the estate without compromising its status as an iconic example of post-war architecture and planning. This paper explores how occupant feedback surveys can inform the development of energy-saving interventions at an atypical case study site.

Media Article (magazine/newspaper)

Barbican residents team up with UCL to save energy and improve comfort

Blog contribution to London Remade website

Barbican Residents Property Survey Results

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Headline reads: A better understanding of how to control flat temperatures through trimmers and fuses could make significant energy savings and cut service charges, study suggests

Barbican Residents Property Survey, Progress Update

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An article written for the BA informing residents of the work being undertaken from the data they provided.


Post occupancy evaluation of Barbican dwellings

Presented at SPONGE Network / UCL Energy Seminar: ‘Energy efficiency and occupant behaviour’.

Utilising resident feedback to inform energy saving interventions at the Barbican

Presented at CIBSE Young Engineers Performance Group (YEPG) Summer Series, Rethinking Energy Performance. The Performance Gap – Does it really exist?

Can POE methods be used to design workable retrofit solutions for iconic and listed buildings?

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Presentation made at the CLUES (Challenging Lock-in through Urban Energy Systems) Energy Case Studies Conference on 08/05/12. Theory and methodology of case study research session.


Comfort for all: fantastic dream or emerging reality?

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Carrie’s work was mentioned in a piece written by Melanie Thompson, editor of the Get Sust! blog, and features on the nbs website