Furman, S., & Hadjri, K. (2025). Wasted expertise: Why retrofit should include residents. Energy Research and Social Science, 119. https://doi.org/10.1016/j.erss.2024.103894

Community empowerment appears in the literature of participatory action research (Minkler, 2004), participatory planning (Jo & Nabatchi, 2018), and community development (Luttrell et al., 2009) as a key element of participatory practices, understanding it as a process that enables communities to take control of their lives and their environments (Rappaport, 2008; Zimmerman, 2000). Many argue that community participation becomes meaningless if it does not lead to, or pass through community empowerment. As the term is being used in diverse and ubiquitous ways, it runs the risk of ending up as an empty definition and a catch-all phrase (McLaughlin, 2015). It is therefore important to specify the perspective through which we will view the term and clarify the nuances.  Since its origins, empowerment has been used in two different ways. Firstly, top-down as the power that had been ‘granted’ by a higher authority, such as the state or a religious institution, and secondly, bottom-up, as a process by which groups or individuals come to develop the capacity to act and acquire power. Examples of the latter can be found in social groups such as feminists working in nongovernmental organizations throughout the global south in the 1970s, who found a way to address social issues and inequalities that enabled social transformation based on women’s self-organization (Biewener & Bacqué, 2015). The term was gradually appropriated by welfare, neoliberal, and social-neoliberal agendas whose priority was individual agency and choice. In neoliberal rationality, empowerment is related to efficiency, economic growth, business productivity, and individual rational choice to maximize profit in a competitive market economy. In social liberalism agendas, empowerment is understood as ‘effective agency’, where ‘agency’ is not an inherent attribute, but something that needs to be constructed through ‘consciousness-raising’ (McLaughlin, 2016). A broader definition sees empowerment as a social action process through which individuals, communities, and organizations take control of their lives in the context of changing the social and political environment to improve equity and quality of life (Rappaport, 2008; Zimmerman, 2000). Rowlands (1997), refers to four types of empowerment: power over, as the ability to influence and coerce; power to, to organize and change existing hierarchies; power with, as the power from the collective action and power within, as the power from the individual consciousness. Using this classification, Biewener & Bacqué (2015), adopting a feminist approach, understand empowerment as a multilevel construct with three interrelated dimensions: 1) an internal, psychological one, where ‘power within’ and ‘power to’ are developed, 2) an organizational, where ‘power with’ and ‘power over’ are strengthened and 3) a social or political level, where institutional and structural change is made possible through collective action. Thus, community empowerment links the individual level, which involves self-determination, growth of individual awareness, and self-esteem, to the collective level, relating critical consciousness and capacity building with the structural level, where collective engagement and transformative social action take place. This view of empowerment, which considers its goals and processes, has a social dimension that is lacking in other approaches that prioritize individual empowerment. Aside from the feminist movements, the philosophy and practices of community empowerment have been greatly influenced by the work of Paulo Freire, a Brazilian educator and an advocate on critical pedagogy. Freire proposed a dialogic problem-solving process based on equality and mutual respect between students and teachers; that engaged them in a process of iterative listening-discussing-acting. Through structured dialogue, group participants shared their experiences, discussed common problems, and looked for root causes and the connections among “problems behind the problems as symptoms” (Freire, 1970). The term conscientization, that Freire proposed, refers to the consciousness that arises through the involvement of people in the social analysis of conditions and their role in changing them. This awareness enables groups to be reflexive and open spaces, to enact change or to understand those limited situations that may deter change (Barndt, 1989). Empowerment can be understood as both a process and an outcome (Jo & Nabatchi, 2018). As a process, it refers to “the development and implementation of mechanisms to enable individuals or groups to gain control, develop skills and test knowledge”(Harrison & Waite, 2015) and it entails the creation of new subjects who have developed a critical consciousness and the formation of groups with a ‘collective agency’ ‚ or ‘social collective identity’ (Biewener & Bacqué, 2015). Empowerment as an outcome refers to “an affective state in which the individual or group feels that they have increased control, greater understanding and are involved and active” (Harrison & Waite, 2015). This can lead to a transformation of the social conditions by challenging the structures and institutionalized forms that reproduce inequalities. The values and the significance of community empowerment can be further applied in the participatory and community-based approaches of the housing sector. Examples of such approaches in the housing provision are the housing cooperatives, and self-developed and self-managed housing groups. Housing cooperatives aim at promoting co-creation to engage future residents, professionals, and non-profit organizations in all the stages of a housing project: problem-framing, designing, developing, cohabiting, managing, and maintaining. Such organisational models stress the importance and pave the way for community empowerment by uniting individuals with similar interests and ideals, enabling them to have housing that responds to their needs, preferences, and values. The participation of the residents aims to strengthen their sense of ownership of the process, the democratic decision-making and management, and the social collective identity, making community empowerment an integral characteristic of cooperative housing initiatives. With this social perspective, residents can gain individual and collective benefits while contributing to fairer and more sustainable urban development on a larger scale (Viskovic Rojs et al., 2020).

Community-led housing involves residents, often organised into community groups, actively participating in planning, designing, financing and managing housing projects to meet their specific needs and preferences. This active involvement nurtures a sense of community ownership and control. This sense of community encompasses  feelings of belonging, shared identity, and mutual support among the residents of a community-led housing initiatives. The term is sometimes used interchangeably with the term "collaborative housing". Collaborative housing also refers to a participatory approach to housing development; however, the focus is on collaboration with the different stakeholders and encompasses various non-profit housing delivery models. While self-organised collective housing efforts are nothing new, a new wave of such initiatives has emerged in Europe since the 2000s (Lang et al., 2018; Tummers, 2016). In recent decades, market-provided housing has been the predominant model in Europe, often prioritising economic gain over the right to adequate shelter. The primary housing options from a tenure perspective are home ownership and rent, which are not always affordable for low-income groups (OECD, 2020, 2020). As a result, many communities are coming together to create secure and affordable housing solutions (Jarvis, 2015). However, the motivations behind these initiatives can vary among the involved groups and may reflect economic, ideological, social or ecological ideals (Caldenby et al., 2020). Some of these motivations include creating affordable homes, exploring more sustainable living practices, and fostering a sense of community and social cohesion. In contrast to other forms of collective housing, community-led housing schemes do not merely emphasize resource or living space sharing: they empower the community to play a proactive role in shaping their built and living environment. According to the Co-operative Councils Innovative Network (2018), community-led housing are developments that meet the following criteria: There is meaningful community engagement throughout the process, even if they did not initiate or build the scheme. The community has a long-term formal role in the ownership or management of the homes. The benefits of the scheme to the local area and/or specified community group are clearly defined and legally protected in perpetuity. Community-led housing can take diverse forms, contingent upon the extent of involvement from the participating communities and the specific type of development. These manifestations range from grassroots groups independently initiating projects to meet their housing needs, to community organizations spearheading housing initiatives. Additionally, developers, such as local authorities or housing associations, can initiate partnerships to provide housing solutions with a community-led component (Lang et al., 2020). Furthermore, concerning the development model, community-led housing can encompass constructing new homes, repurposing vacant homes and managing existing housing units. Each of these approaches has the potential to significantly influence the broader neighbourhood context (Fromm, 2012). The forms of community-led housing include: Housing cooperatives: These are groups of people who provide and collectively manage, homes for themselves as tenants or shared owners, based on democratic membership principles. Cohousing: These consist of like-minded people who come together to provide self-contained private homes for themselves while collectively managing their scheme and often sharing activities, including communal spaces. Cohousing can be developer-led, so it is important to examine whether cases meet the broad definition given above, rather than simply use the term cohousing as a marketing device. Community Land Trusts (CLTs): These are not-for-profit corporations that hold land as a community asset and serve as long-term providers of rental housing or shared ownership. Self-help housing: Small, community-based organisations bringing empty properties back into use, often without mainstream funding and with a strong emphasis on construction skills training and support. Tenant-Managed Organisations: They provide social housing tenants with collective responsibility for managing and maintaining the homes through an agreement with their council or housing association.   These models are adaptable and not mutually exclusive; for example, a co-housing group could choose to establish either a cooperative or a Community Land Trust (CLT). It is important to note that there are variations in how these models are applied in different contexts and countries. For local authorities, community-led housing offers several advantages. It improves the housing supply and the availability of affordable homes, diversifying the housing market while ensuring the long-term affordability of housing units. Additionally, community-led housing supports urban regeneration efforts and repurposes vacant homes. It has the potential to empower communities so that they become more self-sufficient. By involving residents in addressing their housing needs, these initiatives provide opportunities for vulnerable groups, such as the elderly, mono-parental families, etc., to live in supportive communities. Such housing schemes can be developed in various contexts, offering solutions for different housing challenges, including informal settlements, former refugee camps, and the heavily owner-occupied housing markets of South and Eastern Europe.

The in-depth study of energy poverty as a social phenomenon commenced in the late 19th century through the works of British social researchers Booth and Rowntree (O’Connor, 2016). This era was characterised by significant social and economic transformation, and these scholars were troubled by the living conditions and welfare of impoverished urban populations, who were residing in congested and unsanitary environments. Throughout the 20th century, poverty in policy contexts became quite narrowly defined as a lack of income. However, it was another social concern in the UK that led to the development of concepts like ‘fuel poverty’ or ‘energy poverty’ a century after Booth and Rowntree.[i] Following the 1973 oil crisis, the Child Poverty Action Group took the initiative to address how increasing energy costs were affecting low-income households in the UK (Johnson & Rowland, 1976). As essentials like heating, electricity, and fuels became necessary for maintaining a decent standard of living in modern British society, this advocacy group pushed for government financial support. Later, Bradshaw and Hutton (1983) introduced a narrower definition of energy poverty: “the inability to afford adequate heat in the home”. Since then, studies on energy poverty have typically excluded motor fuels, as they fall under transport poverty, a related but separate area of study (Mattioli et al., 2017). Energy poverty, as defined by Bouzarovski and Petrova (2015, p. 33), refers to "the inability to secure or afford sufficient domestic energy services that allow for participation in society." Although the precise boundaries of relevant domestic energy usage are still debated, this definition expands beyond mere heating as it encompasses energy used for cooling, which is particularly relevant in warmer climates (Thomson et al., 2019). Moreover, it enables a socially and culturally dependent understanding of what it means to participate in society (Middlemiss et al., 2019). On 13 September 2023, the European Union (2023) officially defined energy poverty as “a household’s lack of access to essential energy services, where such services provide basic levels and decent standards of living and health, including adequate heating, hot water, cooling, lighting, and energy to power appliances, in the relevant national context, existing national social policy and other relevant national policies, caused by a combination of factors, including at least non-affordability, insufficient disposable income, high energy expenditure and poor energy efficiency of homes”. The doctoral thesis and subsequent book by Brenda Boardman, Fuel Poverty: From Cold Homes to Affordable Warmth (1991), marked a significant breakthrough in energy poverty research. She emphasised the detrimental impact of energy-inefficient housing on health and quality of life. In the decades that followed, substantial literature confirmed her qualitative findings (Thomson et al., 2017). Notably, studies have demonstrated the adverse effects of living in energy poverty on physical health (Liddell & Morris, 2010), mental health (Liddell & Guiney, 2015), stress levels (Longhurst & Hargreaves, 2019), social isolation (Harrington et al., 2005), and absenteeism (Howden-Chapman et al., 2007). Boardman’s work introduced an indicator that has remained influential to this date, although it was not the first attempt to operationalise the concept of fuel poverty (Isherwood & Hancock, 1979). Her ‘2M’ indicator categorises a household as energy poor if it needs to allocate twice the median share of its budget for energy expenses to heat its home adequately. Boardman calculated this threshold to be 10% at that time. Due to its simplicity and ease of comprehension, many governments directly adopted this 10% threshold without considering specific contextual circumstances. Since the early nineties, numerous attempts have been made to develop alternative indicators. Highly influential ones include ‘Low Income High Cost’ (LIHC) by John Hills (2012), ‘Low Income Low Energy Efficiency’ (LILEE) that subsequently became the official British indicator (BEIS, 2022), and a 'hidden' energy poverty indicator by (Meyer et al., 2018). Critiques of these indicators focus, amongst other things, on their simplicity and perceived 'technocratic' approach (Croon et al., 2023; Middlemiss, 2017). This marked the beginning of significant government commitment, initially in the UK and later in other countries to address energy poverty. Although certain forms of cold weather payments had already been introduced by the UK's Conservative administrations, it was under the successive governments of Blair and Brown, following the publication of Boardman's work, that programmes such as the Winter Fuel Payment and Warm Home Discount were implemented (Koh et al., 2012). The UK examples highlight bipartisan support for addressing energy poverty, with both the Conservatives and Labour backing these efforts. This policy objective has also gained momentum in various legislative contexts, leading the EU to incorporate energy poverty alleviation as a fundamental pillar of the European Green Deal and a specific goal of its landmark Social Climate Fund (European Commission, 2021). Over the last three decades, public interest in energy poverty as a 'wicked' problem has surged, particularly during the recent energy crisis. This crisis began in 2021 when energy markets tightened due to a post-pandemic economic rebound, and it worsened dramatically after Russia's invasion of Ukraine in February 2022 (IEA, 2023). Extensive research on the impact of this price surge on energy poverty levels has been carried out throughout Europe and globally (Guan et al., 2023; Simshauser, 2023). Consequently, energy poverty has become a significant focal point in discussions related to the 'just transition,' especially within the realm of energy justice, as it serves as a valuable concept for targeting policies towards a specific vulnerable group in this context (Carrosio & De Vidovich, 2023).     [i] ‘Fuel poverty' and 'energy poverty' are used interchangeably, with the former being more common in the UK and the latter in mainland Europe (Bouzarovski & Petrova, 2015). Previously, scholars in the UK used 'energy poverty' to denote a lack of access to energy and 'fuel poverty' when affordability was the concern (Li et al., 2014). However, this distinction is no longer maintained.

Buildings are responsible for approximately 40% of energy consumption and 36% of greenhouse gas emissions in the EU (European Commission, 2021). Energy retrofit is also referred to as building energy retrofit, low carbon retrofit, energy efficiency retrofit and energy renovation; all terms related to the upgrading of existing buildings energy performance to achieve high levels of energy efficiency. Energy retrofit significantly reduces energy use and energy demand (Femenías et al., 2018; Outcault et al., 2022), tackles fuel (energy) poverty, and lowers carbon emissions (Karvonen, 2013). It is widely acknowledged that building energy retrofit should result in a reduction of carbon emissions by at least 60% compared with pre-retrofit emissions, in order to stabilise atmospheric carbon concentration and mitigate climate change (Fawcett, 2014; Outcault et al., 2022). Energy retrofit can also improve comfort, convenience, and aesthetics (Karvonen, 2013). There are two main approaches to deep energy retrofit, fabric-first and whole-house systems. The fabric-first approach prioritises upgrades to the building envelope through four main technical improvements: increased airtightness; increased thermal insulation; improving the efficiency of systems such as heating, lighting, and electrical appliances; and installation of renewables such as photovoltaics (Institute for Sustainability & UCL Energy Institute, 2012). The whole-house systems approach to retrofit further considers the interaction between the climate, building site, occupant, and other components of a building (Institute for Sustainability & UCL Energy Institute, 2012). In this way, the building becomes an energy system with interdependent parts that strongly affect one another, and energy performance is considered a result of the whole system activity. Energy retrofit can be deep, over-time, or partial (Femenías et al., 2018). Deep energy retrofit is considered a onetime event that utilises all available energy saving technologies at that time to reduce energy consumption by 60% - 90% (Fawcett, 2014; Femenías et al., 2018). Over-time retrofit spreads the deep retrofit process out over a strategic period of time, allowing for the integration of future technologies (Femenías et al., 2018). Partial retrofit can also involve several interventions over time but is particularly appropriate to protect architectural works with a high cultural value, retrofitting with the least-invasive energy efficiency measures (Femenías et al., 2018). Energy retrofit of existing social housing tends to be driven by cost, use of eco-friendly products, and energy savings (Sojkova et al., 2019). Energy savings are particularly important in colder climates where households require greater energy loads for space heating and thermal comfort and are therefore at risk of fuel poverty (Sojkova et al., 2019; Zahiri & Elsharkawy, 2018). Similarly, extremely warm climates requiring high energy loads for air conditioning in the summer can contribute to fuel poverty and will benefit from energy retrofit (Tabata & Tsai, 2020). Femenías et al’s (2018) extensive literature review on property owners’ attitudes to energy efficiency argues that retrofit is typically motivated by other needs, referred to by Outcault et al (2022) as ‘non-energy impacts’ (NEIs). While lists of NEIs are inconsistent in the literature, categories related to “weatherization retrofit” refer to comfort, health, safety, and indoor air quality (Outcault et al., 2022). Worldwide retrofit schemes such as RetrofitWorks and EnerPHit use varying metrics to define low carbon retrofit, but their universally adopted focus has been on end-point performance targets, which do not include changes to energy using behaviour and practice (Fawcett, 2014). An example of an end-point performance target is Passivhaus’ refurbishment standard (EnerPHit), which requires a heating demand below 25 kWh/(m²a) in cool-temperate climate zones; zones are categorised according to the Passive House Planning Package (PHPP) (Passive House Institute, 2016).  

A precise and definitive definition of environmentally sustainable social housing remains elusive. Instead, it encompasses a bundle of interrelated terms such as low-impact buildings, sustainable buildings and environmentally responsible buildings, all of which are interwoven with the characteristics of social housing and its policy and development. This review examines the theoretical underpinnings of social housing and environmental sustainability at the EU level, outlines the challenges of integrating sustainability into housing and proposes an overarching definition of environmentally sustainable social housing. Social housing narratives Elsinga (2012) explains that social housing in the European Union is broadly described as a set of initiatives to provide high-quality and affordable housing for disadvantaged and middle-income groups, usually managed by public authorities (Elsinga, 2012). In the UK and the Netherlands, however, the management of social housing has largely been entrusted to non-profit organisations. This approach contrasts with that of Germany and Spain, where public subsidies are provided to commercial landlords in exchange for a fixed social rent and thus constitute a form of social housing. Granath Hansson and Lundgren (2019) further note that the historical development of social housing in the EU has involved a significant transfer of responsibility from local authorities to non-municipal providers, albeit under highly regulated practices such as the UK's managerialist approach (Granath Hansson & Lundgren, 2019). Priemus (2013) offers a definition that emphasises the regulatory framework and the role of the public sector in regulating social housing (Priemus, 2013). This definition identifies the target group as households unable to compete in the private housing market due to financial, physical or mental health problems or belonging to an ethnic minority or immigrant group. Bengtsson (2017), adopting a target group perspective, characterises social housing as a "system" designed to provide housing to resource-constrained households, with the requirement for their needs to be confirmed (Bengtsson, 2017). Although there is no universally accepted definition of social housing, it can be assumed that social housing functions as a system that supports households with limited financial resources by providing long-term accommodation. This system requires a mechanism to assess the needs of the target groups, ensuring that the housing is provided as a subsidy and not as a self-sustaining unit. Consequently, rents or prices within this system must be affordable and below market prices. Environmental sustainability narratives While there is no definitive definition of environmental sustainability specific to the EU in the literature, several scholars have contributed to understanding this concept from a global perspective and thus influenced its interpretation at the EU level. Notable contributions include those by Hey (2005), Portney (2015), Purvis et al. (2019) and Morelli (2011). Purvis et al. (2019) emphasise that environmental sustainability results from describing environmental protection goals and their interrelationships with broader concepts of the built environment. Environmental sustainability has evolved into a dynamic and multidisciplinary concept that is closely linked to concepts such as resilience, durability and renewability. Morelli (2011) states that environmental sustainability can be applied at different levels and encompasses tangible and intangible aspects (Morelli, 2011). Portney (2015) argues that environmental sustainability goals include conserving natural resources, improving people’s well-being, and promoting industrial efficiency without compromising societal development. The contemporary approach to implementing sustainability focuses on reducing the resource consumption of buildings (such as water and energy) and minimising waste production while improving the quality of the built environment. This approach goes beyond individual buildings and extends to the urban fabric of cities (Berardi, 2012; McLennan, 2004). The EU's approach to environmental sustainability is reflected in its directives, policies, initiatives and guidelines. An example of these initiatives is the European Green Deal (EC, 2019), which aims for a carbon-neutrality across Europe by 2050 while promoting sustainable economic growth (Fetting, 2020; Siddi, 2020). In addition, the EU emphasises the importance of integrating environmental concerns into various policy areas, including energy, transport, agriculture and industry. The EU Circular Economy Action Plan, for example, promotes an economy that minimises waste and supports sustainable consumption and production patterns (EC, 2020). Overall, the EU's approach to environmental sustainability emphasises the need for a comprehensive, integrated, and long-term perspective (Hermoso et al., 2022; Johansson, 2021). This approach considers the economic, social, and environmental dimensions of sustainability and emphasises the importance of international cooperation in addressing global environmental challenges (Fetting, 2020; Hermoso et al., 2022; Siddi, 2020). Integration imperatives and its challenges The realisation of environmentally sustainable social housing presents numerous challenges. The initial investment in sustainable building technologies and materials is often considerable, especially given the limited funds available for social housing projects. Compliance with ever-evolving environmental regulations further complicates the delivery of sustainable social housing. Consequently, there is an urgent need to adapt sustainable practices to different scales of social housing projects, which requires careful planning and adaptation to the specific needs and context of different developments (Oyebanji, 2014). Despite these challenges, the field of sustainable social housing offers significant opportunities for innovation and improvement. Technological progress continuously offers more efficient, cost-effective and sustainable solutions (IEA, 2022). In addition, robust policy frameworks and incentives are crucial for the adoption of sustainable practices (Fetting, 2020). Another crucial element is the active participation of different stakeholders in the design and maintenance of housing, which can significantly improve both sustainability and social cohesion (Shirazi & Keivani, 2019). The way forward Environmentally Sustainable social housing is becoming increasingly important as it represents both a possible future and an ambitious goal. It envisions an environmentally responsible housing sector without compromising its development capacity (Morgan & Talbot, 2001; Oyebanji, 2014; Winston, 2021). It aims to create housing that minimises its environmental footprint, promotes the well-being of its residents and provides affordable housing opportunities. It also aims to meet the housing needs of vulnerable and low-income groups while promoting sustainable development and addressing climate and environmental issues (Udomiaye et al., 2018).

Housing quality is concerned with the conditions and characteristics ensuring it is safe, healthy, comfortable, and sustainable for its occupants. It considers the physical conditions of a dwelling and the social and physical environment surrounding it (Bonnefoy, 2007; Swope & Hernández, 2019). There is increasing pressure to ensure affordable housing meets quality standards in Europe and the UK. Neglecting quality in assessing affordability could perpetuate poor-quality, unsustainable housing, harming both the planet and households' wellbeing (AHC, 2019; Fraser et al., 2023; Haffner & Heylen, 2011; OECD, 2021). This vocabulary entry focuses on housing quality.   Housing quality directly impacts the wellbeing of households by influencing physical and mental health and financial stability. It has been recognised as a crucial determinant of health and wellbeing, as poor housing conditions are linked to numerous health issues, including respiratory and cardiovascular diseases, injuries, and mental health disorders (WHO, 2018). As such, housing quality not only concerns the physical attributes of a dwelling but also its capacity to support the health and wellbeing of its occupants​ (Rolfe et al., 2020).     Levels of Housing Quality   Housing quality can be recognised through various contextual levels, which include:   Physical structures and features of buildings, such as insulation, ventilation systems, materials used, and essential services such as heating, plumbing, and electrical systems (Keall et al., 2010). Internal environment and living conditions, which refer to the atmosphere within a dwelling. These include air quality, light, noise levels, and thermal comfort, all contributing to indoor environmental quality. They could also encompass factors such as overcrowding and cleanliness (Riva et al., 2022). The living conditions arise from the interaction between the building characteristics and the residents, and how they use or treat the dwelling. (Bonnefoy, 2007; Riva et al., 2022). For example, mould can develop due to a lack of proper ventilation systems suitable for the household and dwelling size. Alternatively, a proper ventilation system might be provided; however, occupants may not use it when cooking, bathing or showering (Keall et al., 2010). Household characteristics refer to the behaviours and lifestyles of residents. According to Keall et al. (2010, p. 767), the household level encompasses "social, cultural and economic aspects such as affordability, suitability, security of tenure,” which impact people's needs for space, energy, water, and transport. Additionally, it acknowledges that demographic, psychological, and biological aspects, such as attitudes towards recycling, maintenance, cleaning routines, and use of space, influence lifestyles. External community and infrastructure involve the neighbourhood, regional policies, and global environmental conditions impacting housing quality. Factors such as urban planning decisions, availability of community resources, and neighbourhood safety play crucial roles (Keall et al., 2010; Swope & Hernández, 2019). Regulatory and policy frameworks pertain to the standards and regulations to ensure housing quality. Compliance with these regulations should promote equity in housing practices (Swope & Hernández, 2019). For example, A new set of Consumer Standards established by the Regulator of Social Housing in England aims to improve the quality of social housing and ensure that landlords fulfill their responsibilities to tenants by providing quality homes, transparent operations, and fair tenancy management (Regulator of Social Housing, 2024).     Housing Quality Indicators   Housing quality indicators are vital for assessing the conditions of dwellings. They could address various aspects of housing, such as safety, sustainability, comfort, and suitability for residents. These indicators are essential for understanding the physical state of housing and the living conditions within dwellings. These indicators could serve four purposes:   Measuring housing quality and affordability across countries: Some housing quality indicators could enable meaningful cross-country comparisons to better determine what residents are paying for in terms of quality. The OECD (2021) Policy Brief on Affordable Housing highlighted some housing quality measures to accompany measuring housing affordability, such as the "Overcrowding Rate," "Housing Deprivation Rate," and subjective measures to assess housing affordability and quality based on household perceptions. Elaboration on these measures is available in the Measuring Housing Affordability vocabulary.   Measuring housing quality within a country: Some indicators are used to evaluate the quality of housing schemes to ensure that housing standards are met across different regions. For example, non-decent housing in England is identified with the help of the Housing Health and Safety Rating System (HHSRS) (Department for Communities and Local Government, 2006). HHSRS assesses 29 potential health and safety hazards in residential properties, including structural dangers, toxicity, mould and inadequate heating. Another example is England's Housing Quality Indicators (HQIs) system. Although currently withdrawn, it served as an assessment tool to evaluate housing scheme quality. The HQIs system encompassed four categories: location and proximity to amenities, site-related aspects (landscaping, open spaces, pathways), housing unit features (noise, lighting, accessibility, sustainability), and the external environment (Homes and Communities Agency, 2011).   Measuring housing satisfaction across groups:  Other indicators measure household satisfaction, gauging how well housing meets their expectations and needs. For example, the English Housing Survey (EHS) collects comprehensive data on housing conditions and residents' satisfaction levels across different demographic groups and regions (DLUHC, 2019). It evaluates housing quality, adequacy of amenities, safety measures, and overall satisfaction with the living environment. Thus, it enables identifying targeted improvements needed within the housing sector.   Measuring housing quality of a specific housing scheme: Post-Occupancy Evaluation (POE) could be considered a housing quality indicator in the design and construction context. POE is a process for assessing buildings' performance and functionality after they have been occupied (Hadjri & Crozier, 2009). It could include energy efficiency, indoor environmental quality, and occupant satisfaction (Elsayed et al., 2023). The evaluation involves various methodologies to collect data, which can be objective (measured data) and subjective (occupant feedback), providing insights that could lead to improvements in management practices and future designs. However, in the EU context, this process remains inconsistent (Elsayed et al., 2023). This inconsistency hinders comparing results and gathering insights to improve broader housing quality.   Despite the usefulness of the indicators mentioned above, accurately measuring housing quality is still challenging. The inherent subjectivity of what constitutes "adequate" housing means that perceptions can vary significantly due to influences of cultural, economic, and individual expectations. Furthermore, the technical feasibility of employing comprehensive quality indicators is often limited by outdated or incomplete data on the characteristics of dwellings. These limitations hinder effective housing quality assessment, making it difficult to enforce and update housing standards consistently (OECD, 2021).

Environmental Retrofit Buildings are responsible for approximately 40% of energy consumption and 36% of carbon emissions in the EU (European Commission, 2021). Environmental retrofit, green retrofit or low carbon retrofits of existing homes ais to upgrade housing infrastructure, increase energy efficiency, reduce carbon emissions, tackle fuel poverty, and improve comfort, convenience and aesthetics (Karvonen, 2013). It is widely acknowledged that environmental retrofit should result in a reduction of carbon emissions by at least 60% in order to stabilise atmospheric carbon concentration and mitigate climate change (Fawcett, 2014; Johnston et al., 2005). Worldwide retrofit schemes such as RetrofitWorks, EnerPHit and the EU’s Renovation Wave, use varying metrics to define low carbon retrofit, but their universally adopted focus has been on end-point performance targets (Fawcett, 2014). This fabric-first approach to retrofit prioritises improvements to the building fabric through: increased thermal insulation and airtightness; improving the efficiency of systems such as heating, lighting and electrical appliances; and the installation of renewables such as photovoltaics (Institute for Sustainability & UCL Energy Institute, 2012). The whole-house systems approach to retrofit further considers the interaction between the occupant, the building site, climate, and other elements or components of a building (Institute for Sustainability & UCL Energy Institute, 2012). In this way, the building becomes an energy system with interdependent parts that strongly affect one another, and energy performance is considered a result of the whole system activity. Economic Retrofit From an economic perspective, retrofit costs are one-off expenses that negatively impact homeowners and landlords, but reduce energy costs for occupants over the long run. Investment in housing retrofit, ultimately a form of asset enhancing, produces an energy premium attached to the property. In the case of the rental market, retrofit expenses create a split incentive whereby the landlord incurs the costs but the energy savings are enjoyed by the tenant (Fuerst et al., 2020). The existence of energy premiums has been widely researched across various housing markets following Rosen’s hedonic pricing model. In the UK, the findings of Fuerst et al. (2015) showed the positive effect of energy efficiency over price among home-buyers, with a price increase of about 5% for dwellings rated A/B compared to those rated D. Cerin et al. (2014) offered similar results for Sweden. In the Netherlands, Brounen and Kok (2011), also identified a 3.7% premium for dwellings with A, B or C ratings using a similar technique. Property premiums offer landlords and owners the possibility to capitalise on their  retrofit investment through rent increases or the sale of the property. While property premiums are a way to reconcile          split incentives between landlord and renter, value increases pose questions about long-term affordability of retrofitted units, particularly, as real an expected energy savings post-retrofit have been challenging to reconcile (van den Brom et al., 2019). Social Retrofit A socio-technical approach to retrofit elaborates on the importance of the occupant. To meet the current needs of inhabitants, retrofit must be socially contextualized and comprehended as a result of cultural practices, collective evolution of know-how, regulations, institutionalized procedures, social norms, technologies and products (Bartiaux et al., 2014). This perspective argues that housing is not a technical construction that can be improved in an economically profitable manner without acknowledging that it’s an entity intertwined in people’s lives, in which social and personal meaning are embedded. Consequently, energy efficiency and carbon reduction cannot be seen as a merely technical issue. We should understand and consider the relationship that people have developed in their dwellings, through their everyday routines and habits and their long-term domestic activities (Tjørring & Gausset, 2018). Retrofit strategies and initiatives tend to adhere to a ‘rational choice’ consultation model that encourages individuals to reduce their energy consumption by focusing on the economic savings and environmental benefits through incentive programs, voluntary action and market mechanisms (Karvonen, 2013). This is often criticized as an insufficient and individualist approach, which fails to achieve more widespread systemic changes needed to address the environmental and social challenges of our times (Maller et al., 2012). However, it is important to acknowledge the housing stock as a cultural asset that is embedded in the fabric of everyday lifestyles, communities, and livelihoods (Ravetz, 2008). The rational choice perspective does not consider the different ways that occupants inhabit their homes, how they perceive their consumption, in what ways they interact with the built environment, for what reasons they want to retrofit their houses and which ways make more sense for them, concerning the local context. A community-based approach to domestic retrofit emphasizes the importance of a recursive learning process among experts and occupants to facilitate the co-evolution of the built environment and the communities (Karvonen, 2013). Involving the occupants in the retrofit process and understanding them as “carriers” of social norms, of established routines and know-how, new forms of intervention  can emerge that are experimental, flexible and customized to particular locales (Bartiaux et al., 2014). There is an understanding that reconfiguring socio-technical systems on a broad scale will require the participation of occupants to foment empowerment, ownership, and the collective control of the domestic retrofit (Moloney et al., 2010).

Justice theory is as old as philosophical thought itself, but the contemporary debate often departs from the Rawlsian understanding of justice (Velasquez, Andre, Shanks, & Meyer, 1990). Rawls (1971) argued that societal harmony depends on the extent to which community members believe their political institutions treat them justly. His First Principle of ‘justice as fairness’ relates to equal provision of ‘basic liberties’ to the population. His Second Principle, later referred to as the ‘Difference Principle’, comprises unequal distribution of social and economic goods to the extent that it benefits “the least advantaged” (Rawls, 1971, p. 266).1[1] As this notion added an egalitarian perspective to Rawlsian justice theory, it turned out to be the most controversial element of his work (Estlund, 1996). The idea of a ‘just transition’ was built on these foundations by McCauley and Heffron (2018), who developed an integrated framework overarching the ‘environmental justice’, ‘climate justice’ and ‘energy justice’ scholarships. The term was first used by trade unions warning for mass redundancies in carbon-intensive industries due to climate policies (Hennebert & Bourque, 2011), but has acquired numerous interpretations since. This is because the major transition of the 21st century, the shift towards a low-carbon society, will be accompanied by large disturbances in the existing social order. In this context, a just transition would ensure equity and justice for those whose livelihoods are most affected (Newell & Mulvaney, 2013). A just transition implies that the ‘least advantaged’ in society are seen, heard, and compensated, which corresponds with three key dimensions conceptualised by Schlosberg (2004): distributive, recognitional, and procedural justice. Distributive justice corresponds with Rawls’ Difference Principle and comprehends the just allocation of burdens and benefits among stakeholders, ranging from money to risks to capabilities. Recognitional justice is both a condition of justice, as distributive injustice mainly emanates from lacking recognition of different starting positions, as well as a stand-alone component of justice, which includes culturally or symbolically rooted patterns of inequity in representation, interpretation, and communication (Young, 1990). Fraser (1997) stressed the distinction between three forms: cultural domination, nonrecognition (or ‘invisibility’), and disrespect (or ‘stereotyping’). Procedural justice emphasises the importance of engaging various stakeholders – especially the ‘least advantaged’ – in governance, as diversity of perspectives allows for equitable policymaking. Three elements are at the core of this procedural justice (Gillard, Snell, & Bevan, 2017): easily accessible processes, transparent decision-making with possibilities to contest and complete impartiality. A critique of the just transition discourse is that it preserves an underlying capitalist structure of power imbalance and inequality. Bouzarovski (2022) points to the extensive top- down nature of retrofit programmes such as the Green New Deal, and notes that this may collide with bottom-up forms of housing repair and material intervention. A consensus on the just transition mechanism without debate on its implementation could perpetuate the status quo, and thus neglect ‘diverse knowledges’, ‘plural pathways’ and the ‘inherently political nature of transformations’ (Scoones et al., 2020). However, as Healy and Barry (2017) note, understanding how just transition principles work in practice could benefit the act of ‘equality- proofing’ and ‘democracy-proofing’ decarbonisation decisions. Essentially, an ‘unjust transition’ in the context of affordable and sustainable housing would refer to low-income households in poorly insulated housing without the means or the autonomy to substantially improve energy efficiency. If fossil fuel prices – either by market forces or regulatory incentives – go up, it aggravates their already difficult financial situation and could even lead to severe health problems (Santamouris et al., 2014). At the same time, grants for renovations and home improvements are poorly targeted and often end up in the hands of higher income ‘free-riding’ households, having regressive distributional impacts across Europe (Schleich, 2019). But even when the strive towards a just transition is omnipresent, practice will come with dilemmas. Von Platten, Mangold, and Mjörnell (2020) argue for instance that while prioritising energy efficiency improvements among low-income households is a commendable policy objective, putting them on ‘the frontline’ of retrofit experiments may also burden them with start-up problems and economic risks. These challenges only accentuate that shaping a just transition is not an easy task. Therefore, both researchers and policymakers need to enhance their understanding of the social consequences that the transition towards low-carbon housing encompasses. Walker and Day (2012) applied Schlosberg’s dimensions to this context. They conclude that distributive injustice relates to inequality in terms of income, housing and pricing, recognitional justice to unidentified energy needs and vulnerabilities, and procedural injustice to inadequate access to policymaking. Ensuring that the European Renovation Wave is made into a just transition towards affordable and sustainable housing therefore requires an in-depth study into distributive, recognitional and procedural justice. Only then can those intertwining dimensions be addressed in policies.   [1] To illustrate his thesis, he introduces the ‘veil of ignorance’: what if we may redefine the social scheme, but without knowing our own place? Rawls believes that most people, whether from self-interest or not, would envision a society with political rights for all and limited economic and social inequality.  

According to the Oxford English Dictionary, participation is “the act of taking part in an activity or event”. Likewise, it can also mean “the fact of sharing or the act of receiving or having a part of something.” It derives from old French participacion which in turn comes from late Latin participationem, which means “partaking” (Harper, 2000).  References to participation can be found in many fields, including social sciences, economics, politics, and culture. It is often related to the idea of citizenship and its different representations in society. Hence, it could be explained as an umbrella concept, in which several others can be encompassed, including methodologies, philosophical discourses, and tools. Despite the complexity in providing a holistic definition, the intrinsic relation between participation and power is widely recognised. Its ultimate objective is to empower those involved in the process (Nikkhah & Redzuan, 2009). An early application of participatory approaches was the Participatory Rural Appraisal (PRA) which exerted a significant influence in developing new discourses and practices of urban settings (Chambers, 1994; Friedmann, 1994). In the late 1970s increasing attention was paid to the concept by scholars, and several associated principles and terminologies evolved, such as the participation in design and planning with the Scandinavian approach of cooperative design (Bφdker et al., 1995; Gregory, 2003). Participation in design or participatory design is a process and strategy that entails all stakeholders (e.g. partners, citizens, and end-users) partaking in the design process. It is a democratic process for design based on the assumption that users should be involved in the designs they will go on to use (Bannon & Ehn, 2012; Cipan, 2019; Sanoff, 2000, 2006, 2007). Likewise, participatory planning is an alternative paradigm that emerged in response to the rationalistic and centralized – top-down – approaches. Participatory planning aims to integrate the technical expertise with the preferences and knowledge of community members (e.g., citizens, non-governmental organizations, and social movements) directly and centrally in the planning and development processes, producing outcomes that respond to the community's needs (Lane, 2005). Understanding participation through the roles of participants is a vital concept. The work of Sherry Arnstein’s (1969) Ladder of Citizen Participation has long been the cornerstone to understand participation from the perspective of the redistribution of power between the haves and the have-nots. Her most influential typological categorisation work yet distinguishes eight degrees of participation as seen in Figure 1: manipulation, therapy, placation, consultation, informing, citizen control, delegated power and partnership. Applied to a participatory planning context, this classification refers to the range of influence that participants can have in the decision-making process. In this case, no-participation is defined as designers deciding based upon assumptions of the users’ needs and full-participation refers to users defining the quality criteria themselves (Geddes et al., 2019). A more recent classification framework that also grounds the conceptual approach to the design practice and its complex reality has been developed by Archon Fung (2006) upon three key dimensions: who participates; how participants communicate with one another and make decisions together, and how discussions are linked with policy or public action. This three-dimensional approach which Fung describes as a democracy cube (Figure 2), constitutes a more analytic space where any mechanism of participation can be located. Such frameworks of thinking allow for more creative interpretations of the interrelations between participants, participation tools (including immersive digital tools) and contemporary approaches to policymaking. Aligned with Arnstein’s views when describing the lower rungs of the ladder (i.e., nonparticipation and tokenism), other authors have highlighted the perils of incorporating participatory processes as part of pre-defined agendas, as box-ticking exercises, or for political manipulation. By turning to eye-catching epithets to describe it (Participation: The New Tyranny? by Cooke & Kothari, 2001; or The Nightmare of Participation by Miessen, 2010), these authors attempt to raise awareness on the overuse of the term participation and the possible disempowering effects that can bring upon the participating communities, such as frustration and lack of trust. Examples that must exhort practitioners to reassess their role and focus on eliminating rather than reinforcing inequalities (Cooke & Kothari, 2001).

The performance gap in retrofit refers to the disparity between the predicted and actual energy consumption after a retrofit project, measured in kWh/m2/year. This discrepancy can be substantial, occasionally reaching up to five times the projected energy usage (Traynor, 2019). Sunikka-Blank & Galvin (2012) identify four key factors as contributing to the performance gap: (1) the rebound effect, (2) the prebound effect, (3) interactions of occupants with building components, and (4) the uncertainty of building performance simulation outcomes. Gupta & Gregg (2015) additionally identify elevated building air-permeability rates as a factor leading to imbalanced and insufficient extract flowrates, exacerbating the performance gap. While post occupancy evaluation of EnerPhit—the Passivhaus Institut certification for retrofit—has shown far better building performance in line with predictions, the human impact of building users operating the building inefficiently will always lead to some sort of performance gap (Traynor, 2019, p. 34). Deeper understanding of the prebound effect and the rebound effect can improve energy predictions and aid in policy-making (Galvin & Sunikka-Blank, 2016). Therefore, the ‘prebound effect’ and the ‘rebound effect’, outlined below, are the most widely researched contributors to the energy performance gaps in deep energy retrofit.   Prebound Effect The prebound effect manifests when the actual energy consumption of a dwelling falls below the levels predicted from energy rating certifications such as energy performance certificates (EPC) or energy performance ratings (EPR). According to Beagon et al. (2018, p.244), the prebound effect typically stems from “occupant self-rationing of energy and increases in homes of inferior energy ratings—the type of homes more likely to be rented.” Studies show that the prebound effect can result in significantly lower energy savings post-retrofit than predicted and designed to achieve (Beagon et al., 2018; Gupta & Gregg, 2015; Sunikka-Blank & Galvin, 2012). Sunikka-Blank & Galvin’s (2012) study compared the calculated space and water heating energy consumption (EPR) with the actual measured consumption of 3,400 German dwellings and corroborated similar findings of the prebound effect in the Netherlands, Belgium, France, and the UK. Noteworthy observations from this research include: (1) substantial variation in space heating energy consumption among dwellings with identical EPR values; (2) measured consumption averaging around 30% lower than EPR predictions; (3) a growing disparity between actual and predicted performance as EPR values rise, reaching approximately 17% for dwellings with an EPR of 150 kWh/m²a to about 60% for those with an EPR of 500 kWh/m²a (Sunikka-Blank & Galvin, 2012); and (4) a reverse trend occurring for dwellings with an EPR below 100 kWh/m²a, where occupants consume more energy than initially calculated in the EPR, referred to as the rebound effect. Galvin & Sunikka-Blank (2016) identify that a combination of high prebound effect and low income is a clear indicator of fuel poverty, and suggest this metric be utilised to target retrofit policy initiatives.   Rebound Effect The rebound effect materializes when energy-efficient buildings consume more energy than predicted. Occupants perceive less guilt associated with their energy consumption and use electrical equipment and heating systems more liberally post-retrofit, thereby diminishing the anticipated energy savings (Zoonnekindt, 2019). Santangelo & Tondelli (2017) affirm that the rebound effect arises from occupants’ reduced vigilance towards energy-related behaviours, under the presumption that enhanced energy efficiency in buildings automatically decreases consumption, regardless of usage levels and individual behaviours. Galvin (2014) further speculates several factors contributing to the rebound effect, including post-retrofit shifts in user behaviour, difficulties in operating heating controls, inadequacies in retrofit technology, or flawed mathematical models for estimating pre- and post-retrofit theoretical consumption demand. The DREEAM project, funded by the European Union, discovered instances of electrical system misuse in retrofitted homes upon evaluation (Zoonnekindt, 2019). A comprehensive comprehension of the underlying causes of the rebound effect is imperative for effective communication with all retrofit stakeholders and for addressing these issues during the early design stages.   Engaging residents in the retrofit process from the outset can serve as a powerful strategy to mitigate performance gaps. Design-thinking (Boess, 2022), design-driven approaches (Lucchi & Delera, 2020), and user-centred design (Awwal et al., 2022; van Hoof & Boerenfijn, 2018) foster socially inclusive retrofit that considers Equality, Diversity, and Inclusion (EDI). These inclusive approaches can increase usability of technical systems, empower residents to engage with retrofit and interact with energy-saving technology, and enhance residents’ energy use, cultivating sustainable energy practices as habitual behaviours. Consequently, this concerted effort not only narrows the performance gap but simultaneously enhances overall wellbeing and fortifies social sustainability within forging communities.

As the name suggests, Post-Occupancy Evaluation (POE) is the process of assessing the performance of a building once it has been occupied. It is often conflated and falls under the umbrella of Building Performance Evaluation (BPE) (Boissonneault & Peters, 2023; Preiser, 2005; Stevenson, 2018). Other definitions refer to POE as any activity intended to assess how buildings perform and the level of satisfaction of their users, ranging from simple survey questionnaires to indoor environmental quality (IEQ) measurements, which makes its scope very broad (Li et al., 2018). Nevertheless, in the case of POE, the focus should be on the occupants’ experience of the building and the impact of spaces on their behaviour and well-being (Watson, 2003 in Sanni-Anibire et al., 2016). It is commonly suggested that POE should be conducted at least a year after the handover and occupation of the building so that users can experience and test it under different weather conditions (RIBA et al., 2016). In the context of housing, housing providers, developers and architecture practices can benefit from enquiring what makes a good design from the occupants’ point of view. A systematic and rigorous POE combined with periodic user experience surveys can be very beneficial as it helps to improve relationships with tenants and provide a better picture of the quality of the housing stock. Thus, POEs do not only help to balance the scale between the social, economic and environmental aspects of buildings but also revitalise the role of research in the whole life cycle of projects. Despite its potential benefits for the various stakeholders engaged in the production of the built environment, POE is not a widespread practice in the sector. There is a notable absence of literature and research on the subject (Durosaiye et al., 2019; Hadjri & Crozier, 2009). However, since the 2010s, there has been a growing academic interest in POE, as evidenced by the increasing number of scientific publications, including studies related to post-occupancy evaluation (Li et al., 2018). There is a consensus in literature that learning from experience, whether from unintended consequences of ill-considered design or from successful projects, through the active involvement of occupants and users of buildings is a pathway for innovation. POE is commonly considered as an activity that requires long-term commitment and can be time and resource-consuming. This is a limitation that can be explained by the short-term logic of the construction sector and the fleeting commitment of developers, especially private and profit-driven, to the communities and clients they work with. In the same vein, the question of who is responsible for commissioning and conducting a POE represents the biggest barrier to its widespread implementation in the sector (Cooper, 2001). Concerns are inextricably linked to the cost and scope of the assessment, the equipment and professionals involved, and the possibility of being held accountable for flaws that might be exposed by the activity. Discussions around the importance of inspecting buildings after completion to assess their environmental performance have gained momentum in recent decades as a consequence of the evidenced climate crisis and the significant share of carbon emissions attributable to activities related to the built environment (according to UNEP (2022), 37 per cent of CO2 emissions in 2021). Nonetheless, the emergence of POE as a concept for the built environment dates back to the 1960s in the USA, where it was originally used to assess institutional facilities and fell mainly within the remit of facility managers (Preiser, 1995). Later, the PROBE (Post Occupancy Review of Building Engineering) research conducted between 1995 to 2002 on 23 non-residential case studies in the UK helped spread the concept among the whole gamut of professionals involved in the design and construction of buildings (Bordass et al., 2001; Cohen et al., 2001). With respect to design and housing, the work of Marcus and Sarkissian (1986) in Housing as if People Mattered is worth mentioning. In this book, the authors have outlined a set of design guidelines derived from evidence gathered through POEs. Their research was conducted with the aim of comprehending people's preferences and dislikes about their neighbourhoods and homes, utilizing a people-centred perspective that delves into " the quality of housing environments from a social standpoint, as defined by residents" (p.5). Their approach to POE is grounded in viewing housing as a process rather than a mere product. They propose rethinking the relationship between the designer and inhabitant, extending beyond the completion of buildings. This perspective aligns with that of Brand (1995), who views buildings as intricate systems governed by the 'Shearing layers of change', a concept developed from Duffy's proposal (Duffy & Hannay, 1992). Accordingly, buildings are understood as layered structures in which time plays a pivotal role in the way they interact with each other and with the user. As Duffy stated, quoted in Brand (1995, p.12): “The unit of analysis for us isn’t the building, it’s the use of the building through time. Time is the essence of the real design problem.” This renders it necessary to go back to the building once finished and continue doing so throughout its lifecycle. The levels of POE The literature distinguishes between three ‘levels of effort’ at which POE can be conducted, which differ mainly in terms of the thoroughness and purpose of the assessment: indicative, investigative, and diagnostic (Hadjri & Crozier, 2009; Preiser, 1995; Sanni-Anibire et al., 2016). These levels vary in methods and the degree of engagement of researchers and participants, and encompassing the phases of planning, conducting and applying. They can be described briefly as follows: Indicative: This level provides a general assessment of the most important positive and negative aspects of the building from the users' point of view. It involves a brief data collection period, characterised by walk-throughs, interviews and survey questionnaires with occupants. It is not exhaustive and may reveal more complex problems that need to be addressed with an investigative or diagnostic POE. It can be completed in a few hours or days. Investigative: If a relevant problem identified in an indicative POE requires further research, an investigative POE is carried out. This second level implies a more robust amount of data to be collected, the use of more specialised methods, and possibly the disruption of occupants' routines and building use due to the prolonged engagement in the research endeavour. It can take weeks to months to complete. Diagnostic: This level is characterised by its approach which is both longitudinal and cross-sectional. It may involve one or more buildings and a research process that may take months to a year or more to complete. It is more akin to research conducted by specialised institutions or scholars. The scope can be very specific but also have sector-wide implications. Possible applications of the information gathered through POE A more recent review of the literature on POE studies highlights the variegated range of purposes behind it: impact of indoor environmental quality on occupants, design and well-being, testing of technologies, informing future decision-making or feedforward, and impact of building standards and green rating systems, to name a few (Boissonneault & Peters, 2023; Li et al., 2018). The breadth of applications and rationale for conducting POE studies show that it is a powerful tool for assessing a wide array of issues in the built and living environment, and partly explain the interest it holds for researchers. However, the industry is still lagging behind, which hinders the dissemination and further implementation of the findings and results.  More collaboration between academia and industry is therefore crucial as the great impact lies in applying POE and BPE as a structural part of the sector’s practice. Moreover, since POE primarily relies on fieldwork and the collection of empirical data, a more comprehensive assessment that incorporates mixed methods and a systematic approach can yield greater benefits for the entire building production chain. The collected feedback, analysis and resulting conclusions can create learning loops within organisations and bring about real changes in the lives of current and future building users. Therefore, a robust POE should be accompanied by the implementation of the concomitant action plan to address the problems identified. For this purpose, a theory of change approach can be helpful. In this sense, POE can become a very effective facility management tool (Preiser, 1995). Some examples of the varied uses of data provided by robust POE and BPE include the creation of databases for informed decision-making, benchmarking and integration into BIM protocols or GIS-powered tools. In this sense, generating data that can be compared and benchmarked is critical to the long-term impact and value for money of undertaking the activity. It is therefore imperative to recognise POE for its benefits rather than viewing it as a liability or a mere nice-to-have feature. On the other hand, POE inherently involves a wide range of disciplines within the built environment, including design, engineering, psychology, policy and finance, among others. This multidisciplinary aspect can be leveraged to promote transdisciplinary research to help better understand the relationships between buildings and people It delves into the impact of these relationships, considering human behaviour and well-being. This perspective is often referred to as the building performance-people performance paradigm, as denominated by other POE researchers (Boissonneault & Peters, 2023). Architectural geographers, for instance, have explored the various meanings and emotions ascribed by inhabitants to buildings, particularly council estates in the UK, through actor-network theory-informed research (Jacobs et al., 2008, 2016; Lees, 2001; Lees & Baxter, 2011). Similarly, the work of organisations such as the Quality of Life Foundation encompassed in the Quality of Life Framework (Morgan & Salih, 2023; URBED, 2021), has highlighted the link between the places where we live and its impact on our quality of life through systematic POEs conducted in collaboration with social housing providers and local authorities. Amid the climate emergency and the pressing need to curtail carbon emissions, there is now a need for the sector to innovate and mitigate the impact of building construction and operation. It has been argued that sustainability cannot be achieved only by adopting energy-efficient technologies or by promoting certifications such as LEED, Passivhaus, or assessment protocols such as BREEAM (Building Research Establishment Environmental Assessment Methodology). As discussed earlier, conducting these assessments is an effective tool to mitigate and solve the discrepancy between the expected energy performance of the designed building vis à vis that of its real-life counterpart, the so-called performance gap. POE can be used to ascertain the social performance gap by including qualitative and well-being-related indicators (Brown, 2018). In this way, buildings are evaluated not only in terms of their ability to comply with building regulations and environmental goals, but also in meeting social objectives in order to provide greater sustainability and affordability, particularly in housing.

A universal definition of social housing is difficult, as it is a country-specific and locally contextualised topic (Braga & Palvarini, 2013). This review of the concept focuses on social housing in the context of the UK from the late 1980s, which Malpass (2005) refers to as the phase of ‘restructuring the housing and welfare state’, to the early 2000s, known as the phase of the ‘new organisation of social housing’. In response to previous demands for housing, such as those arising during the Industrial Revolution, and recognising the persistent need to address the substandard quality of housing provided by private landlords in the UK (Scanlon et al., 2015), the primary objective of social housing has historically been to enhance the overall health conditions of workers and low-income populations (Malpass, 2014; Scanlon et al., 2015). However, this philanthropic approach to social housing changed after the Second World War when it became a key instrument to address the housing demand crisis. Private initiatives, housing associations, cooperatives and local governments then became responsible for providing social housing (Carswell, 2012; Scanlon et al., 2015). Social housing in the UK can be viewed from two perspectives: the legal and the academic (Granath Hansson & Lundgren, 2019). Along these two perspectives, social housing is often analysed based on four main criteria: the legal status of the landlord or provider, the tenancy system or tenure, the funding mechanism or subsidies, and the target group or beneficiaries (Braga & Palvarini, 2013; Carswell, 2012; Granath Hansson & Lundgren, 2019). From a legal perspective, social housing maintained its original goals of affordability and accessibility during the restructuring period in the late 1980s. However, citing the economic crisis, the responsibility for developing social housing shifted from local authorities to non-municipal providers with highly regulated practices aligned with the managerialist approach of the welfare state (Granath Hansson & Lundgren, 2019; Malpass, 2005; Malpass & Victory, 2010). Despite the several housing policy reviews and government changes, current definitions of social housing have maintained the same approach as during the restructuring period. Section 68 of the Housing and Regeneration Act 2008, updated in 2017, defines social housing as low-cost accommodation provided to people whose rental or ownership needs are not met by the commercial market (HoC, 2008; 2017, pp. 50-51). The Regulator of Social Housing, formerly the Homes and Communities Agency, has adopted the earlier definition of social housing and clarified which organisations provide it across the UK. These organisations include local authorities, not-for-profit housing associations, cooperatives, and for-profit organisations (RSH, 2021). In contrast, the National Housing Federation emphasises the affordability of social housing regardless of the type of tenure or provider (NHF, 2021). From an academic perspective, Malpass (2005) explains that during the restructuring phase, social housing was defined as a welfare-supported service – although it did have limitations, which meant that funding principles shifted from general subsidy to means-tested support for housing costs only, which later formed the basis for the Right to Buy Act introduced by the Thatcher government in the early 1980s (Malpass, 2005, 2008). The restructuring phase, however, came as a response to the housing 'bifurcation' process that began in the mid-1970s and accelerated sharply from the 1980s to 1990s (Kleinman et al., 1998; Malpass, 2005). During this phase, the role of social housing in the housing system was predominantly residual, with greater emphasis placed on market-based solutions, and social housing ownership concerned both local authorities and housing associations (Malpass & Victory, 2010). This mix has influenced the perception of social housing in the 'new organisation' phase as a framework that regulates public housing intervention for specific groups and focuses on enabling non-municipal providers (Malpass, 2005, 2008; Malpass & Victory, 2010). Currently, as Carswell (2012) explains, social housing plays an important role in nurturing a variety of initiatives aimed at providing ‘good-quality’ and ‘affordable’ housing for vulnerable and low-income groups (Carswell, 2012). Oyebanji (2014) sees social housing as any form of government-regulated housing provided by public institutions, including non-profit organisations (Oyebanji, 2014). Additionally, Bengtsson (2017) describes social housing as a system that aims to provide households with limited means, but only after their need has been confirmed through testing (Bengtsson, B, 2017 as cited in Granath Hansson & Lundgren, 2019). To a great extent, social housing in the UK can be seen as a service system that is intricately linked to the welfare state and influenced by political, economic, and social components. Despite being somehow determined by common factors and actors,  the relationship between social housing and the welfare state can sometimes be complex and subject to fluctuations (Malpass, 2008). In this context, the government plays a vital role in shaping and implementing the mechanisms and practices of social housing. While the pre-restructuring phase focused on meeting the needs of the people by increasing subsidies and introducing the right to buy (Stamsø, 2010), the aim of the restructuring phase was to meet the needs of the market by promoting economic growth (privatisation, market-oriented policies and reducing the role of local authorities) (Stamsø, 2010; Malpass, 2005) . The new organisational phase, on the other hand, works to meet and balance the needs of all, with people, politics and the economy becoming more intertwined. Welfare reform legislation passed in 2010 aims to enable people to meet their needs, but through 'responsible' subsidies, leading to a new policy stance that has been described as 'neoliberal' thinking (Hickman et al., 2018). However, there are still no strict legal requirements for the organisation and development of social housing as an independent service system, and most of the barriers to development are closely related to the political orientation of the government, rapid changes in housing policy and challenges arising from providers' perceptions of existing housing policy structures (Stasiak et al., 2021).

From the three pillars of sustainable development, economic, environmental and social, the latter  involving social equity and the sustainability of communities, has  been especially neglected. Ongoing problems caused by conflicting economic, environmental and social goals with regard to the processes of urbanisation continue. underpinning economic growth that contradict principles of environmental and social justice (Boström, 2012; Cuthill, 2010; Winston, 2009). Research on sustainable development highlights the need for further investigation of social sustainability (Murphy, 2012; Vallance et al., 2011). Social sustainability has been interpreted as an umbrella term encompassing many other related concepts; “social equity and justice, social capital, social cohesion, social exclusion, environmental justice, quality of life, and urban liveability” (Shirazi & Keivani, 2019, p. 4). A vast number of studies have been dedicated to defining social sustainability by developing theoretical frameworks and indicators particularly relevant to urban development and housing discourse (Cuthill, 2010; Dempsey et al., 2011; Murphy, 2012; Woodcraft, 2012). However, with a lack of consensus on the way of utilising these frameworks in a practical way, especially when applied to planning, social sustainability has remained difficult to evaluate or measure. Consequently, planning experts, housing providers and inhabitants alike understand social sustainability as a normative concept, according to established social norms, and less as an opportunity to critically examine existing institutions. Vallance et al (2011) provide three categories to analyse social sustainability, development, bridge and maintenance sustainability: (a) social development improves conditions of poverty and inequity, from the provision of basic needs to the redistribution of power to influence existing development paradigms; (b) the conditions necessary to bridge social with ecological sustainability, overcoming currently disconnected social and ecological concerns; and (c) the social practices, cultural preferences as well as the environments which are maintained over time. Maintenance social sustainability particularly deals with how people interpret what is to be maintained and includes “new housing developments, the layout of streets, open spaces, residential densities, the location of services, an awareness of habitual movements in place, and how they connect with housing cultures, preferences, practices and values, particularly those for low-density, suburban lifestyles” (Vallance et al., 2011, p. 345). Therefore, the notion of maintenance is especially important in defining social sustainability by directly investigating the established institutions, or “sets of norms” that constitute the social practices and rules, that in turn, affect responsibilities for planning urban spaces. A conceptual framework that appears frequently in social sustainability literature is that of Dempsey et al. (2011)⁠ following Bramley et al. (2009), defining social sustainability according to the variables of social equity and sustainability of community and their relationship to urban form, significantly at the local scale of the neighbourhood. In terms of the built environment, social equity (used interchangeably with social justice) is understood as the accessibility and equal opportunities to frequently used services, facilities, decent and affordable housing, and good public transport. In this description of local, as opposed to regional services, proximity and accessibility are important. Equitable access to such local services effectively connects housing to key aspects of everyday life and to the wider urban infrastructures that support it. Sustainability of community is associated with the abilities of society to develop networks of collective organisation and action and is dependent on social interaction. The associated term social capital has also been used extensively to describe social norms and networks that can be witnessed particularly at the community level to facilitate collective action (Woolcock, 2001, p. 70). They might include a diversity of issues such as resident interaction, reciprocity, cooperation and trust expressed by common exchanges between residents, civic engagement, lower crime rates and other positive neighbourhood qualities that are dependent on sharing a commitment to place (Foster, 2006; Putnam, 1995; Temkin & Rohe, 1998). In fact, “the heightened sense of ownership and belonging to a locale” is considered to encourage the development of social relations (Hamiduddin & Adelfio, 2019, p. 188). However, the gap between theoretical discussions about social sustainability and their practical application has continued. For example, the emphasis of social sustainability as a target outcome rather than as a process has been prioritised in technocratic approaches to planning new housing developments and to measuring their success by factors which are tangible and easier to count and audit. Private housing developers that deal with urban regeneration make bold claims to social sustainability yet profound questions are raised regarding the effects of gentrification (Dixon, 2019). Accordingly, the attempted methods of public participation as planning tools for integrating the ‘social’ have been found to be less effective - their potential being undercut due to the reality that decision-making power has remained at the top (Eizenberg & Jabareen, 2017). Therefore, social sustainability is not a fixed concept, it is contingent on the interdependence of the procedural aspects (how to achieve social sustainability) and substantive aspects (what are the outcomes of social sustainability goals) (Boström, 2012). From this point of view, social sustainability reveals its process-oriented nature and the need to establish processes of practicing social sustainability that begin with the participation of citizens in decision-making processes in producing equitable (i.e. socially sustainable) development. As a dimension of sustainable development that is harder to quantify than the economic or environmental aspects, the operationalisation of social sustainability goals into spatial, actionable principles has remained a burgeoning area of research. In such research, methods for enhancing citizen participation are a particularly important concern in order to engage and empower people with “non-expert” knowledge to collaborate with academic researchers.

Techno-optimism refers to the belief that advances in technology will improve humanity, enhance quality of life, and solve critical problems including climate change, health issues and social inequality (Danaher, 2022). According to Danaher (2022), techno-optimism assumes technology will ensure “the good does or will prevail over the bad” (p.54). Techno-optimists believe that technological innovation is a key driver for economic growth and can provide solutions to many of the pressing challenges faced by contemporary society (Wilson, 2017). Keary (2016) links faith in technological optimism to an unshakable commitment to economic growth. Technological change modelling (TCM), he argues, has shifted the terms of environmental debate, pulling efforts away from ‘green’ ecologism (associated with degrowth movements), and toward techno-optimism; a belief that mitigation pathways should rely on technological advancements. Techno-optimism emerges from enlightenment ideals, whereby reason and scientific progress are seen as pathways to improving human conditions and capabilities by overcoming “existential risk” (Bostrom, 2002) through technological advancements (Wilson, 2017). Hornborg (2024) criticises techno-optimism for its failure to address ecological and social inequalities exacerbated by technology. Further, technological solutions often address symptoms rather than root causes, leading to a superficial treatment of complex problems (Wilson, 2017).  Hornborg, using Marx’s commodity fetishism and World Systems Theory as his guide (Marx, 1990), seeks to unmask modern assumptions about what technology is. Both capitalists and certain left-wing thinkers exalt technology, viewing it as embodying human progress — a promethean mode of thinking. This overlooks, however, the social relations and material, energetic, and metabolic flows needed to maintain technological systems. Technology needs a “sociometabolic reconceptualization” (Hornborg, 2024, p. 28). Historically, technological progress in the world’s industrial core, was dependent on unequal social relations and colonial patterns of extraction from non-industrial peripheries. Shifting to green technologies, in Horrnborg’s view, will involve repeating these inequities: sugar-ethanol, or electric powered cars, for instance, will rely on exploited land in Brazil and the cobalt-rich Congo. “High tech cores versus their exploited peripheries” (Hornborg, 2024, p. 38), recasts the colonial industrial core-periphery dynamic (Wolf et al., 2010), exacerbating ecological and social inequalities. By attributing too much power to technology itself, techno-optimists may neglect the need for conscious and deliberate governance of technological change (Bostrom, 2002, p. 11). Further, it is crucial to maintain a balanced perspective that recognises both the opportunities and the limitations of technological advancements (Wilson, 2017). Social, political, and cultural contexts must shape technological outcomes. Danaher (2022) argues through collective effort, it is possible to create the right institutions and frameworks to guide technological development towards beneficial ends. Technological innovation plays a key role in deep energy retrofit (DER), which relies on three main technical improvements to reach end point performance targets, measured in kWh/m2/year: increased thermal insulation and airtightness; improving the efficiency of systems such as heating, lighting, and electrical appliances; and installation of renewables such as photovoltaics (Institute for Sustainability & UCL Energy Institute, 2012). Techno-optimism in DER has led to the widespread adoption of ground source and air source heat pumps, such as mechanical heat and ventilation systems (MVHR) (Traynor, 2019), to mechanically stabalise indoor air temperatures (Outcault et al., 2022), LED lighting smart systems (Bastian et al., 2022), and upgraded systems for heating and hot water (Roberts, 2008). There are many concerns with techno-optimism in DER: (1) the gap between predicted and actual energy performance can reach as high as five times the prediction (Traynor, 2019), (2) the adoption of techno-optimism does not consider the certainty of technological obsolescence, (3) inoperable windows due to mechanical heating and ventilation increases the risk of future overheating, and cooling costs, and (4) DER disregards architectural vernacular and passive energy strategies, including cross ventilation, thermal mass, and solar gains. In social housing retrofit, non-energy benefits including comfort, modernity, health, and safety, (Amann, 2006; Bergman & Foxon, 2020; Broers et al., 2022)—negated in techno-optimism—are often more important to social housing residents than energy-related benefits. Further, technological innovation in retrofit is often tested on social housing (Morgan et al., 2024), despite housing tenants from marginalised groups, to convince private markets to adopt technologies.