FEEDBACK

In the end, the success or failure of buildings is decided on by the users who occupy them. Hardly any architect or client would maintain that he or she was indifferent to the fate of buildings after their completion. But systematic surveys of users are only carried out in the rarest of cases. The users’ personal attitudes and their wealth of experience affect how they feel in a space and how they judge it. Nonetheless, the well-being of people in buildings can be explained scientifically and expressed in objective, quantitative terms. In the past decades, scientists have developed methods to do so. Wouldn’t it be possible to make more of these methods and models? What if the knowledge about what contributes to user well-being was used to design buildings for better well-being in the first place?


There is a lot that can be learnt from existing buildings in order to generate new knowledge for future architecture. Architects and engineers employ many different strategies to assess the successes and failures of their designs. Yet who could be more competent to judge than the true experts on everyday life – the people who actually live and work in the buildings? In the last 40 years, a whole range of methods has been developed to quantify residents’ well-being and their level of satisfaction with their living conditions.

By Jakob Schoof
Photography by Ivan Brodey

Tegnestuen Vandkunsten: CPH Shelter/CPH Village, Copenhagen
CAN BUILDING DESIGN learn from its own successes and mistakes? How do you measure the success of a design if not by looking at the well-being and health of the users? And how can you find out whether the indoor climate really does enhance people’s well-being?
   The idea that the systematic evaluation of existing buildings could generate knowledge that will be useful when designing new ones is not new. A method, first deployed in the USA and Great Britain, was developed in the 1960s and 1970s that consisted of scrutinising existing buildings and asking the users about their experiences with the building. It is known by the collective English term ‘post-occupancy evaluation’ (POE).1 The first user surveys were carried out towards the end of the sixties in student halls of residence in America. In the seventies, the method was expanded to include hospitals, office buildings, schools, social housing, and military facilities. Since the 1990s, post-occupancy evaluation has become a more common procedure, particularly for offices and administrative buildings. There are two main reasons for this: on the one hand, it was recognised that the buildings often consumed far more energy than previously calculated; on the other, the numbers of complaints about the poor indoor climate and malfunctioning technical equipment began to escalate. Investigations in the USA and in Germany have shown that the average user satisfaction in energy-efficient or LEED certified office buildings is no higher than that reported for most office buildings.2 Experts put the blame for the performance gap between theory and practice primarily on the buildings’ increasingly complex technical equipment and the inadequate induction given to subsequent facilities managers and users during the handover.
   Meanwhile, in some countries the legislators began to react. In the UK, for example, all new-build public buildings since 2016 are subjected to a three-year monitoring process that includes an annual user survey.3 But the situation for residential buildings is quite different – and not just in the UK. There are only a few systematic studies of people’s well-being at home. According to Fionn Stevenson, professor at the School of Architecture of the University of Sheffield, the rarity of post-occupancy evaluation in this sector is linked to residents’ expectations of privacy: “Simply gaining access to people’s homes, which are private by their nature, can present a real barrier.” One aspect that may play a role in this could be the fact that the clients of office buildings have a vested interest in a healthy and productive workforce, while the owners of residential buildings do not benefit directly from the improved well-being of their tenants. Nevertheless, there are a few hopeful developments, which will be discussed below.

Measurements and surveys: the methods of post-occupancy evaluation
In principle, post-occupancy evaluations can be carried out at any time during the lifecycle of a building to provide key insights: hindsight is useful as it allows the planning process and its success to be analysed; current insights can be used to adapt the building to the needs of users, while foresight can be used to learn about planning similar buildings in the future.
   According to Fionn Stevenson, a POE offers numerous benefits: it reduces lifecycle costs and the environmental impact of buildings, decreases the developer’s liability risks, minimises the expenditure required for maintenance, increases user satisfaction, and generates valuable knowledge that can be incorporated into making future designs better. A post-occupancy evaluation usually includes the following steps:


“People are the best measuring instruments. They are just harder to calibrate.”

Gary Raw


  • a tour of the building together with the users and/or the facility manager 
  • technical measurements (e.g. room temperature, heating energy consumption, light/level of illumination, amount of CO2 in rooms, air humidity, ...) 
  • user surveys using printed or digital questionnaires, or – more rarely structured interviews 

Technical measurements can, in themselves, provide interesting information about user behaviour in residential buildings. It is well known, for example that heating energy consumption in buildings that are otherwise identical in terms of construction can vary by a factor of three or even more, depending on user behaviour. In nine recently renovated apartment buildings in Karlsruhe, researchers from RWTH Aachen attempted to uncover the possible causes for this.4 To do so, they measured room temperatures based on thermostat settings but also determined ventilation behaviour using window contacts. They found that almost all combinations of temperatures considered agreeable by tenants and fresh air requirements were present. Some tenants preferred room temperatures of 24°C but kept their windows open 24 hours a day even in winter, while other tenants were content with an ambient temperature of 19°C and almost never aired their rooms.
   But in order to get to the bottom of the motives for such behaviour and find out whether residents actually feel comfortable in the indoor climate they have chosen for themselves, one has to talk to them. Only a combination of measured physical data and qualitative statements by residents will reveal what the British building evaluation specialist Bill Bordass calls “the story behind the data”. Together with Fionn Stevenson and Adrian Leaman, he wrote in an article published in 2010: “In our experience, nothing betters case studies of named buildings backed by thorough data collection, benchmarked against a national sample finishing with a list of lessons learned, preferably including reflections on the results by the parties directly involved, and especially the design team.” 5

What do we want to know? Questionnaires and their contents
Numerous questionnaires – some of them standardised – have been developed in the last 30 years as a means of surveying the users of buildings (Fig. 5). The questionnaires most commonly used internationally are the British Building Use Studies (BUS) Questionnaire6 and the CBE Occupant Indoor Environmental Quality Survey developed at University of California, Berkeley7. Both were originally developed for office buildings, schools, and other non-residential buildings; since 2010, the BUS questionnaire has also become available in a version for residential buildings. The questionnaire has also been deployed when carrying out user surveys for the certification systems NABERS (Australia) and BEES (New Zealand). The international engineering consultancy Arup now curates the commercial version of the BUS questionnaire. Adrian Leaman of BUS estimates that around 60% of all surveys that use the BUS option are carried out by planning offices and 40% by university institutes. When the questionnaire was developed, he says, care was taken to keep it as short as possible and to focus on aspects that designers and managers can actually influence. Leaman believes it is important that the questionnaire is both practical and viable because, when they survey users, planners and academics are often pursuing very different and, in many cases, incompatible goals: “POE in the university sector has another agenda. It is often far too statistical and/or modelling orientated. And the work does not
Tegnestuen Vandkunsten: CPH Shelter/CPH Village, Copenhagen
Tegnestuen Vandkunsten: CPH Shelter/CPH Village, Copenhagen
speak clearly to a designer audience. It is an academic echo chamber, not assisted by the conventions of academic publishing, especially writing styles.”
   Adrian Leaman believes it is important that survey results are published; it is the only way to achieve broad improvements in the planning quality and user-friendliness of buildings. Unfortunately, according to Leaman, many planners and building contractors do not pay much heed to this recommendation – in particular when it is a question of making less flattering individual results public. In the UK, the Usable Buildings Trust charity was established in 2002 to pursue a wider dissemination of results, in a readable and understandable form, but with limited success.8
   Furthermore, many user surveys of residential buildings continue to use questionnaires that have been customised to the respective research project or building. According to Adrian Leaman, this often means that results are not comparable, and cannot be successfully benchmarked against a common data set. Surveys almost always include questions about the user’s satisfaction with the size of the apartment, ease of use of the heating system and (where present) ventilation system, along with room climate parameters such as daylight, temperature and air quality. Additional questions can cover almost anything in or on the building – the view, privacy, the furnishings, cleanliness, the materials used, the atmosphere in the room, or technical installations. Occasionally, questionnaires may also delve into very fundamental issues. They can even include questions on the user’s satisfaction with the dwelling’s water and electricity supply − if such supplies cannot be taken for granted in that country.
   At the other end of the development spectrum are highly efficient buildings and energy-plus houses of the type currently being built in many European countries. More than 30 residential buildings that comply with energy-plus standards have been constructed in Germany in the last four years as part of the research programme “Efficient House Plus”. Researchers working at the Berlin Institute for Social Research surveyed the residents for the purposes of sociological monitoring.9 They focused particularly on how residents coped with the domestic technology installed in the buildings, but they also looked at users’ energy consumption behaviour. Resident’s attitudes towards the installed technology tended to vary quite considerably, ranging “from delight to scepticism”. However, the majority of people surveyed reported that the operation of the heating and ventilation systems was not yet intuitive for everyone. Many residents were also sceptical about the automatic regulation of the technological installations and expressed their preference for installing only as much technology in their homes as necessary. The respondents also made ambivalent statements about their energy consumption behaviour; most of them said that, since moving into an energy-plus house, they had become far more aware of their own energy consumption. The various displays in the houses, which constantly show energy consumption in real-time, certainly contributed to this increased awareness. But only a minority of the residents stated that they had actually changed their everyday habits since living in the new house.

Quantitative determination of well-being: The Housing Well-being Inventory
Bernd Wegener, professor of social sciences at Humboldt University in Berlin, and his colleague Moritz Fedkenheuer have developed a new approach to obtaining a quantitative understanding of housing well-being. The Housing Well-being Inventory (HWI) is based on the fundamental premise that well-being encompasses more than just the usual comfort


“The elephant isn’t in the room.
It is the room.”

Bill Bordass


parameters such as temperature, daylight supply and air quality. But what does this ‘more’ consist of? To find out, Wegener and Fedkenheuer initially carried out numerous interviews with students but also with test families such as residents of the VELUX LichtAktiv Haus in Hamburg. Based on the responses, they consolidated ten dimensions of housing well-being that were summarised into three groups (Fig. 4). The two social scientists used a questionnaire with 29 statements (items) to determine how pronounced the dimensions of well-being were in certain buildings and for their residents. When responding to the questionnaire, residents had to specify how much they agreed with each individual statement. Statements ranged from “I feel at home in my apartment” to “My apartment needs to be renovated” to “It’s too light where I sleep”. Two to three items were assigned to every dimension of housing well-being to improve the reliability of the results.
   With the HWI, Wegener and Fedkenheuer also aimed to find out how people’s well-being at home affects their energy consumption behaviour. To identify this, they added additional modules to their questionnaire. The modules contained questions about environmental awareness, the preferred style of living, the residents’ attitudes to housing technology and to their own health.

International comparison of housing satisfaction: the VELUX Healthy Homes Barometer
The Housing Well-being Inventory method can be also used to determine the housing satisfaction of entire populations and communities. This is precisely what Wegener and Fedkenheuer did with the Healthy Homes Barometer in 2015 and 2016, working together with the VELUX Group and the market research institutes Operate A/S and Wilke.10 For the second edition of the Barometer, published in 2016, a selected representative sample of 14,000 people from 14 European countries were given a catalogue of 20 questions. This catalogue of questions is a reduced selection of the 29 items of the Housing Well-being Inventory. During their survey, researchers also found that 77% of Europeans do not have optimal sleeping conditions at home and that 82% live in rooms that are occasionally too cold in winter. Complaints of overheating are even more common − 87% of Europeans stated that their home was sometimes too warm in summer.
   The study confirmed the association between ventilation, daylight and respondents’ subjective feeling about their health; people who reported that they regularly aired their rooms and had enough daylight at home assessed their own health as significantly better compared to people who lacked fresh air and natural light in their home.
   The size of their home, the condition it was in (i.e., whether it required renovation or not) and relations with the neighbours had the biggest impact on housing satisfaction. According to Moritz Fedkenheuer, this is a clear indication that post-occupancy evaluations in residential buildings should not just be limited to questions about classic comfort parameters − socio-demographic factors and the building’s location also play a role. Owners of apartments are, on average, more satisfied with the apartment than tenants; people living in the country tend to be more satisfied than city dwellers; and younger people are more likely to be content than elderly persons. Moreover, it was found that the newer the house or apartment, the more likely its residents were to feel comfortable. On average, North Europeans were the most likely to be satisfied with their living conditions, followed by people living in Western, Eastern and Southern Europe. For those living in the Mediterranean area, housing satisfaction depended very
DataAE +Harquitectes: Students' hall of residence in Sant Cugat del Vallès

Figure 2

Design strategies aligned with user needs and expectations according to Bill Bordass and Adrian Leaman. Whereas essential functions that do not require user interaction should operate silently in the background (upper left quadrant), all systems requiring interaction with the users should be either easy to understand (upper right quadrant) or provide the necessary flexibility for unpredictable changes and individual needs (lower right quadrant).

Source: Adapted from A. Leaman, ‘User needs and expectations’, in Buildings, Culture and Environment: Informing Local and Global Practices, Oxford: Blackwell Pub. (2003)


Figure 3

Conceptual model for the evaluation of building performance by Marans and Spreckelmeyer. Our environmental satisfaction and our behaviour inside a building are not just influenced by the objective environmental attributes of the building, but also by how we ‘frame’ our experience of the building, i.e.: what buildings have we experienced in the past, and what standards are commonly applied to buildings in the culture that we live in?

Source: R. W. Marans & K. F. Spreckelmeyer, Evaluating Built Environments, Chicago: The University of Michigan (1981).






Figure 4

First-order and second-order well-being factors according to the Housing Well-being Inventory (HWI). The size of the home is not correlated to any of the other factors and hence forms its own second-order category. However, its influence on overall housing well-being has been shown to be less significant than that of both the affective and functional well-being.

Source: Bernd Wegener


DataAE +Harquitectes: Students' hall of residence in Sant Cugat del Vallès
DataAE +Harquitectes: Students' hall of residence in Sant Cugat del Vallès
Surrounded by overgrown meadowland, the architectural college of Sant Cugat del Vallès near Barcelona has stood alone at the edge of the town ever since its foundation. Now, 57 modular student flats have been built there. Two long, two-storey blocks made of prefabricated concrete modules flank a central, open courtyard. The individual apartments are private areas to which students can retreat, whereas the communal life of the students takes place in the green courtyard. According to the calculations of the architects, the energy requirement of the flats is around 70% less than the maximum allowed by Spanish law.
Technical University of Darm- stadt, Department of Design  and Building Technology: students' hall of residence 'Cubity' in Frankfurt
Technical University of Darmstadt, Department of Design and Building Technology: students' hall of residence 'Cubity' in Frankfurt 
Cubity is a real-life laboratory for new forms of communal student living. There are only eight square metres of available space for each occupant, whereas the communal areas are all the more spacious. The build envelope is formed by a translucent polycarbonate facade in which windows can be opened only at the corners of the building. A modular rooflight supports the natural ventilation. Only the prefabricated living cubes in the building are actively heated and cooled. The large communal area can only be slightly temperated with the help of an underfloor heating system, which allows the temperatures to fluctuate between around 18 and 28 °C depending on the season and the amount of sunshine that enters.
much on the size and state of renovation of their home, while in Eastern Europe the indoor room climate had a big impact on housing satisfaction.
   The survey also provided interesting answers to the question of why people did not air their rooms more often or heat their homes more in winter. Technical shortcomings, such as too little insulation or an inadequate heating system, were some of the reasons cited. The wish – or the necessity – to save on energy costs at home is quite common. But lack of knowledge is also a possible explanation; many people overestimate the heat loss caused by a short period of intensive ventilation. And many more people ventilate their homes after getting up in the morning than before going to bed. And yet a sufficient supply of fresh air in the evening is essential for healthy sleep.
   Often it is not abstract knowledge but actual experience that changes people’s attitudes towards housing. This was also demonstrated by the evaluation of the LichtAktiv Haus and the VELUX Model Homes 2020 buildings. People often only perceive the difference between a dark home and a light home when they experience it in everyday life. Or to put it differently − we simply do not know what we are missing until we see an abundance of daylight in our new home with our own eyes.

New ways of living and what the residents think about them
For the upcoming years, Bernd Wegener and Moritz Fedkenheuer have planned another research project in which they want to go back to the roots, as it were, of post-occupancy evaluations. Student halls of residence were the first buildings whose residents were systematically asked about their housing satisfaction. In many respects, halls of residence are the laboratories of the future for living in expanding urban centres; they are places where people who cannot afford large apartments live together in confined spaces, and they are where new ways of communal living that go beyond traditional nuclear families can be tried out.
   In the coming years, the two social scientists want to carry out sociological investigations in three student halls of residence. The first is a fairly traditional hall of residence with many small individual apartments; the second is a so-called Vario living concept where residents can vary the size of communal and private spaces using movable wall elements; and the third is the experimental ‘Cubity’ hall of residence. In Cubity, each resident only has eight square meters of private space. In return, the students will be provided with a generous communal area.
   The Vario hall of residence, based on a design by the architecture firm Drexler Guinand Jauslin, will be built in Heidelberg as part of the International Building Exhibition (IBA). Cubity has already been built. It was designed by students of TU Darmstadt under the direction of Anett-Maud Joppien and Manfred Hegger, and was completed in Frankfurt at the end of 2016. Here again, the evaluation will be based on the criteria of the Housing Well-being Inventory, although the Inventory was expanded by several aspects specific to living in halls of residence. Compared to typical single-family apartments and houses, social interaction, privacy, customisability and productivity (how easy is it to study undisturbed in the rooms) tend to play a significantly greater role in the case of Cubity & Co.
   In addition to questionnaires and individual and group interviews, Moritz Fedkenheuer also uses methods of participant observation to study how students live together. To do this, he spends several days living in the halls of residence himself; while staying there he records his own subjective impressions. He additionally logs as many activities in the halls as possible: Where do students meet each other? What is the communal area used for and how intensively is it used? The interviews with the residents also aim primarily to obtain a better understanding of how the different rooms are used. The students are asked to tell where they stay, how often they linger there and for what purpose. But they are also asked to give free rein to their creativity by designing – based on their own personal experiences with the house – an alternative Cubity that would meet their needs even better.

What to do with the knowledge acquired? A concept for new feedback systems
But what can the knowledge obtained about the conditions under which people feel comfortable at home be used for? In the short term, it can be used to carry out small modifications in the investigated buildings or to improve the usability of the technical installations. In the long term, the knowledge can be used to design even better residential buildings tailored to the needs of their residents. But the knowledge obtained could also be used to motivate residents to behave in a more energy-conscious way. Nowadays, many energy-efficient new buildings use display screens to inform residents about their energy consumption in real-time. The hope is that this feedback will encourage people to be aware and use energy more responsibly. But experience has shown that the result of these display screens is often only a one-off effect; energy consumption tends to drop by a few percentage points in the first few weeks after moving in and then remains constant at the new level – or may even increase again as residents revert back to their old habits. “To achieve sustained changes in behaviour, the feedback needs to be much more personalised and should include concrete tips on changing behaviour,” says Bernd Wegener. And feedback systems also need to spot what the right motivation could be. Instead of attempting to entice residents by energy savings of a few pennies, it might be better to tempt them by the prospect of better well-being, Wegener thinks. The system’s energy-saving tips should be adapted to take account of the building’s efficiency standard and the residents’ attitudes. How pronounced is their overall energy awareness? How much time do they spend at home each day? In a research project funded by the EU, Bernd Wegener and Moritz Fedkenheuer have developed a concept for such an interactive feedback system. There can be no doubt that a lot of development efforts will still be needed to implement their concept. But if this is what could close the feedback loop between buildings and users, then ultimately both sides could benefit − the residents and the environment.

Outlook: rarely has building evaluation been as important as it is today
How does new knowledge arise? In science, this is an everyday occurrence. Hypotheses are proposed, tested and, depending on the results, accepted or rejected. Architects would also do well to regularly examine their built hypotheses if they want to adequately meet future challenges. The evaluation of existing buildings makes an important contribution to this. It is the missing link that can complete the learning curve in architecture and ensure that future generations of buildings perform better in practice than those of today. To do so, it is clear that buildings need to contribute to their users’ well-being.
   Although experts – including those who were interviewed for this issue of Daylight/Architecture, such as Marilyne Andersen, Davidson Norris and Matthias Schuler – repeatedly stress the importance of post-occupancy evaluation, the method still leads a niche existence in Europe. At the moment, however, it is receiving valuable impetus from two directions − the social sciences and information technology. For residential buildings in particular, there are now promising new approaches to the quantification of occupants’ well-being. In future, intelligent control systems could be able to learn the individual preferences of their users and adapt the interior climate accordingly. But even if this happens someday, it will not be the end of development. Even then, existing buildings will supply architects and planners with valuable information so that they can expand their wealth of experience and generate knowledge for future designs.
Technical University of Darm- stadt, Department of Design  and Building Technology: students' hall of residence 'Cubity' in Frankfurt
Technical University of Darm- stadt, Department of Design  and Building Technology: students' hall of residence 'Cubity' in Frankfurt

Figure 5

Questionnaires used for post occupancy evaluation in residential buildings, with the respective criteria and aspects covered.


Name
Building Use Studies
Design Quality Indicator
CBE Occupant Indoor Environmental Quality Survey
Effizienzhaus Plus questionnaire
Housing Well-Being Inventory
Developed by
Building Use Studies Ltd. (UK)
Construction Industry Council (UK)
Center for the Built Environment, University of Berkeley (USA)
Berliner Institut für Sozialforschung (DE)
Bernd Wegener, Moritz Fedkenheuer (DE)
Year
1985 (original version) 2010 (residential version)
2002
2004
2013
2013
Applicable to residential buildings
yes
Partly
Partly (with adaptations)
Yes
Yes
Criteria/aspects covered
  • Location 

  • Space

  • Layout

  • Storage

  • Appearance

  • needs

  • Temperature in winter
  • Air quality in winter

  • Temperature in summer

  • Air quality in summer

  • Noise

  • Lighting

  • Health (perceived)

  • Personal control

  • Design (overall)

  • Changes in lifestyle

  • Utilities costs

  • Use 

  • Access

  • Space

  • Character & innovation

  • Form & materials

  • Internal environment

  • Urban & social integration

  • Performance

  • Engineering systems

  • Construction

  • General satisfaction

  • Building

  • General satisfaction

  • workspace

  • Ease of interaction

  • Building cleanliness

  • Comfort of furnishing

  • Amount of light

  • Building maintenance

  • Colours and textures

  • Workspace cleanliness

  • Amount of space

  • Furniture adjustability

  • Visual comfort

  • Air quality

  • Visual privacy

  • Noise

  • Temperature

  • Sound privacy

  • Size

  • Appropriateness of the floor plan

  • Brightness

  • Neighbourhood

  • Indoor climate

  • Functionality of the heating system/ heating controls

  • Functionality of the ventilation system/ ventilation controls

  • Health/Allergic reactions

  • Energy balance

  • Ease of Interaction

  • Ease of maintenance

  • Consumption behaviour (related to energy and other resources)

  • Emotional attachment

  • Size

  • Modernity

  • Daylight

  • Neighbourhood

  • Heating control

  • Energy consumption

  • Humidity

  • Quality of sleep

  • Indoor climate


Notes
  1. The Usable Buildings Trust from the UK uses a narrower definition of POE, applying this term only to building evaluations carried out as part of the overall design and building process. For surveys done purely for research purposes, the more generic term ‘building evaluation’ is used.
  2. S. Altomonte, S. Schiavon (2013): Occupant satisfaction in LEED and non-LEED certified buildings. Building and Environment, Vol. 68, pp. 66–76 A. Wagner et al. (2015): Nutzerzufriedenheit in Bürogebäuden. Fraunhofer IRB Verlag, Freiburg
  3. cf. BIM Task Group: Government Soft Landings. www.bimtaskgroup.org/gsl/ 
  4. Nutzerverhalten bei Sanierungen berücksichtigen. Projektinfo 02/2015. bine Informationsdienst, Eggenstein-Leopoldshafen 2015. www.bine.info/publikationen/publikation/nutzerverhalten-bei-sanierungen-beruecksichtigen/ 
  5. A. Leaman , F. Stevenson, B. Bordass (2010) Building evaluation: practice and principles, Building Research & Information, 38:5, 564–577 
  6. www.busmethodology.org 
  7. www.cbe.berkeley.edu/research/survey.htm
  8. www.usablebuildings.co.uk 
  9. Berliner Institut für Sozialforschung: Sozialwissenschaftliche Evaluation des Modellprogramms Effizienzhaus Plus Standard. Berlin 2015. www.forschungsinitiative.de/effizienzhaus-plus/forschung/forschung-netzwerk/sozialwissenschaftliches-monitoring
  10. www.velux.com/article/2016/europeans-on-healthy-living-the-healthy-homes-barometer-2016