Indoor Environmental Comfort - Integrating Universal Design & Energy Efficiency in Home Renovations

Abstract

Sustainability in the built environment is now firmly in the societal agenda with intensification of efforts by governmental and non-governmental organizations, policy makers, businesses, and academics. Energy efficiency (EE) in buildings is seen as a key component of an environmentally sustainable built environment. At the same time Universal design (UD), driven by demographic changes and evolution of values towards a more inclusive society, is embraced as a strategy for improving social sustainability in the built environment. The research presented in this thesis is inspired by the drive to improve the overall sustainability of the existing housing stock by increasing the adoption of environmental and social sustainability measures related to energy efficiency and universal design respectively. Despite both belonging to the vision for a more sustainable built environment, there is little interdisciplinary research that considers energy efficiency and universal design in tandem. This separation is a missed opportunity to better fulfil the residents’ immediate and long-term needs through the simultaneous execution of EE and UD renovations. However, we have observed that there is a mismatch between the needs and aspirations of homeowners considering renovation, which tend to focus on improving their comfort, and the policies which purportedly incentivize and facilitate these home renovations. Therefore, the main objective for this research is to propose a new frame for policy and research on sustainable home renovations from the perspective of owneroccupiers by developing an inhabitant/renovator-centered understanding of the role of comfort in home renovations. It is guided by the following research question: “How can comfort be used to merge UD (LLL) and EE measures in order to increase the adoption of both in housing renovations?” The thesis can be understood in 3 consecutive parts which iteratively and progressively reveal the next step. Part I, comprising Chapters 2 and 3, explores the relationship between EE and UD in theory and practice. In Chapter 2 a comparative review of research on EE and UD is undertaken revealing that they are complementary but not directly compatible at a conceptual level. Although UD and EE started in similarly narrow technical scope and at a similar time in the 1970s, EE has developed into an engineering dominated field driven by measurable outcomes. On the other hand, UD research has broadened dramatically towards diversity and inclusion and is still struggling with its various definitions. The key insight was that EE and UD are different types of concepts (product & process respectively) which makes their combination conceptually incorrect. This makes it difficult to speak of EE and UD in similar terms. While acknowledging the depth of the academic debate on the definition UD, this is sidestepped in favour of focusing on the outcomes of a UD process. For this reason, the Lifelong living term (Levenslangwonen in Dutch), considered to be a product of a UD process, is used instead in order to facilitate the integration with Energy efficiency without engaging in theoretically problematic comparisons. This opens the door for a “middleman”, or unifying concept to be introduced. When analysing Energy efficiency research on adoption incentives comfort had surfaced as important driver of EE adoption. Comfort, in the general sense, is also an implicit outcome of the UD process and Lifelong living measures. This became more apparent when the actual EE and Lifelong living (LLL) measures combined in practice and the motivations of the homeowners were analysed (see Chapter 3). The case study of 9 homes that have implemented both EE and LLL measures, a first on this topic, suggests that these homeowners tend to have a future-orientated thinking, unsurprising for people who implemented measures whose benefit is only visible in the long term. Surprisingly, they saw neither conflicts nor synergies in combining EE and LLL, indicating that the advantages of the joint execution, beyond not having to engage in renovation twice, are not obvious to homeowners. The combination is “just common sense” because it future proofs their home and gives them “peace of mind” and “comfort”. One of the unexpected but important insights of this study was that the homeowners saw the building professionals (architect, contractor etc.) as unhelpful, and sometimes outright against their vision. These are precisely the advisors who should have the knowledge, experience, and potential to guide the client towards more sustainable homes, but were not trusted by the homeowners in the study. This insight influenced the direction and requirements of the Comfort Tool designed later in the research process, as a communication tool between building professionals and homeowners engaging in renovation. The comfort thread was followed up in Part 2 (Chapters 3 and 4) which explores with the meaning of comfort and proposes an Indoor Environmental Comfort framework. Chapter 4 begins with a new hypothesis (EE+LLL=Comfort) and presents more literature research on comfort and its meaning in EE, UD and other literature. It demonstrates that “Comfort” is a relevant and essential topic for those who renovate their homes. The many studies on incentives and motivation show comfort consistently among the top 2-3 reasons for building or renovating a (environmentally) sustainable home. For LLL and UD improving comfort of access and use for as many people as possible is the fundamental goal implicit in all the various definitions. Therefore, further investigation of the meaning of comfort in the context of home renovations is carried out in three qualitative studies. They corroborate the holistic meaning of comfort observed in the case studies. Comfort at home was described with terms related to EE such as thermal comfort and fresh air, and to LLL such as light, accessibility, aesthetics, ease of maintenance etc. For the respondents in these studies, comfort at home encompasses physical, social and psychological elements of dwelling in a building. These studies provide the first suggestion of comfort indicators from the perspective of inhabitants. The comfort indicators are analysed and distilled by comparing them with other studies and methods which take a holistic view of building quality. Because the indicators were derived from people’s intuitive understanding of comfort at home, they are not distinct and mutually exclusive. There is overlap and interdependence between indicators and their meaning can vary depending on the reader’s interpretation. With the comfort indicators in hand, which represent the combination of EE and LLL, we established the Indoor Environmental Comfort framework. The framework places Indoor Environmental Comfort in relation to Energy efficiency, Lifelong living, Universal design, and Comfort in the more general definition. Indoor Environmental Comfort is presented as an overarching concept consisting of both EE and LLL aspects, while being a smaller subsection of the all-encompassing meaning of Comfort applicable to the context of home renovation. The list of IEC indicators is then tested in a survey presented in Chapter 5 to see whether they were indeed relevant to attendees in a construction fair. The results of the survey, in combination with other feedback led to a revised list of indicators for IEC. A final list of 16 indicators is proposed in Chapter 6. In Part 3 (Chapters 6-8) the knowledge gained in the previous four chapters is operationalised, via the development and deployment of the Comfort Tool method. Chapter 6 is of particular importance as it brings together many of the results from the previous four chapters and proposes a revised IEC framework, introduces the Comfort Tool method (CT), as well as the comforttool.be online app as a proof of concept of the CT. The Comfort Tool is designed to elicit the subjective level of Indoor Environmental Comfort from the perspective of the inhabitants. The CT takes a user-centred approach and rests on an interdisciplinary set of theoretical constructs bringing together knowledge from psychology, nursing, design and building science. It has three objectives: 1. Raise awareness of EE and LLL measures 2. Simple to use and understand, even by laymen. 3. Improve communication between residents and experts The Comfort Tool method is translated into a 6 step process and built as a web application at www.comforttool.be with enough detail to be a functional proof of concept. The CT process is aligned with the Person-Environment Fit theory in the sense that it measures the preferences/needs of the person and then assesses the perceived performance of environment (i.e. the House). The result is a “Comfort Profile” - Comfort Fit and an Improvement Potential - that is unique to the person and the house being analyzed. The Comfort profile can be used as a starting point for reflecting on the renovation plans and deeper discussions with architects and other building experts. The functional prototype of the Comfort Tool is then deployed in three different studies as a assessment tool but also to gather more information on the tool itself. First, in Chapter 7, we circle back to the beginning and investigate the bi-directional relationship between EE+LLL and IEC – i.e., what is the effect of EE+LLL on Indoor Environmental Comfort, and vice-versa, what is the effect on EE and LLL measures when renovation is approached through Indoor Environmental Comfort. The CT is used in four renovated case study houses linked to two Living Labs to assess comfort perception before and after renovation. It is then used as an aid for designers in a masterclass with architecture students. The results indicate that there is a positive bi-directional relationship between EE, LLL and IEC: more EE and LLL measures lead to higher Indoor Environmental Comfort, and a focus on (IE) comfort during design leads to implementation of EE and LLL measures. The CT captured several cobenefits of energy efficiency and LLL measures which indicates that Indoor Environmental Comfort can be an effective concept for highlighting the co-benefits of deep renovations from the perspective of the inhabitants. With these results, we can claim to have provided a detailed answer to the central research question on the role that comfort can play in merging EE and LLL in order to increase the adoption of both. Finally, in Chapter 8, the comfort profiles data that users of the Comfort Tool web app provided was analyzed to gain insights into the comfort preferences and the perceived comfort conditions (of their current homes) for Flemish homeowners. Although this study does not directly contribute to answering the research question, it is an example of the applicability of the Comfort Tool method as an instrument for deeper insights about the preferences and needs in home renovations from the perspective of the inhabitant – both at a one-on-one level, and from a larger population. It can be argued that the Comfort Tool helps to transform a design process into a more UD process. Although its development was made possible by using a product of UD (i.e. Lifelong Living criteria), the Comfort Tool has come full circle by facilitating the process rather than pushing specific design requirements. Renovation policy and incentive programs for sustainable renovations can leverage homeowners’ innate aspirations and preferences in their expectations of a home renovations. There is scope for such an approach to improve take up of sustainable measures related to UD and EE, particularly in the private owner-occupied housing market in Belgium. This thesis can be seen as a starting point for further research on a holistic and cohesive treatment of environmental and social sustainability issues in housing as a response to increasingly urgent expectations at the European and regional levels for sustainable renovations.