Indoor Thermal Comfort
Area: Design, planning and building
Improving indoor thermal comfort is a widely agreed motivate for housing retrofit (Femenías et al., 2018; Outcault et al., 2022; Sojkova et al., 2019; Zahiri & Elsharkawy, 2018). Low carbon retrofit of existing social housing tends to be driven by cost, the use of eco-friendly products, and energy savings (Sojkova et al., 2019). Energy savings are particularly important in colder climates where households require larger energy loads for space heating and thermal comfort and are therefore at greater risk of fuel (energy) poverty (Sojkova et al., 2019; Zahiri & Elsharkawy, 2018). Femenías et al.’s (2018) extensive literature review on property owners’ attitudes to energy efficiency argues that renovations are 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” (Outcault et al., 2022, p.3) refer to comfort, modernity, health, safety, education, and better indoor air quality (Amann, 2006; Bergman & Foxon, 2020; Broers et al., 2022; Outcault et al., 2022). In poorly maintained social housing, however, the desire to improve indoor air quality and thermal comfort will have an impact on energy consumption. Occupants will, for example, use extra heating to feel comfortable in a damp, mouldy, or cold home. (Zahiri & Elsharkawy, 2018).
There are three main technical improvements to low carbon retrofit: (1) enhancing the building fabrics thermal properties; (2) improving systems efficiency; and (3) renewable energy integration (Institute for Sustainability & UCL Energy Institute, 2012). In order for the Passivehaus Institut’s EnerPHit Retrofit Plan to meet Passivhaus standards for indoor air quality, homes must achieve high levels of air tightness complemented by a mechanical ventilation system including heat recovery (MVHR). Specifically, “airtightness of a building must achieve an air change per hour rate of less than 0.6 at 50 Pa of pressure (n50), and have ventilation provided by either a balanced mechanical heat recovery ventilation or demand-controlled ventilation systems” (McCarron et al., 2019, p.297). This airtightness concept is revered for saving energy, avoiding structural damage, and contributing to thermal comfort (Bastian et al., 2022) while requiring no natural ventilation such as open windows. Mechanical HVAC units alter indoor air temperature, air movement, ventilation, noise levels, and humidity (Outcault et al., 2022). But despite known benefits to physical health and clean air, this may not lead to optimum user-comfort. This is because social housing residents have unique housing needs that differ from homeowners (Sunikka-Blank et al., 2018) and cannot be predicted without resident engagement, as residents are experts in the way they live and use their homes (Boess, 2022; Gianfrate et al., 2017; Walker et al., 2014).
Post Occupancy Evaluation after retrofit has found that social housing residents are often unfamiliar with mechanical systems and their sustainable benefits, especially when retrofit occurs without resident input (Garnier et al., 2020). This can lead to misuse, overheating, the prebound effect, and the rebound effect where affordable energy bills lead to excessive heating—at times 25-26°C (Zoonnekindt, 2019)—contributing to performance gaps as high as five times the predicted energy consumption (Traynor, 2019). Other households considered mechanical systems to be bulky, ugly, and noisy, prompting removal, lack of use, and at times emotional distress (Lowe et al., 2018). DREEAM’s Berlin pilot site found one household blocking mechanical ventilation with tissue paper because they considered the air too cold and residents “haven’t been informed about the positive impact of a well working ventilation on their health and on the energy efficiency of the heating in their apartment” (Zoonnekindt, 2019). DREEAM continued the project with Green Neighbours (Zoonnekindt, 2019), an innovative engagement program co-designed with and for residents to better inform mechanical systems usage. However, literature shows (Boess, 2022; Gianfrate et al., 2017; Walker et al., 2014) that informing residents on how to use mechanical systems is unlikely to change use-habits or adequately combat performance gaps. In order to change residents’ energy behaviours, resident stakeholders should be integrated in retrofit decision-making.
References
Amann, J. T. (2006). Valuation of Non-Energy Benefits to Determine Cost-Effectiveness of Whole-House Retrofits Programs: A Literature Review. http://aceee.org
Bastian, Z., Schnieders, J., Conner, W., Kaufmann, B., Lepp, L., Norwood, Z., Simmonds, A., & Theoboldt, I. (2022). Retrofit with Passive House components. Energy Efficiency, 15(1). https://doi.org/10.1007/s12053-021-10008-7
Bergman, N., & Foxon, T. J. (2020). Reframing policy for the energy efficiency challenge: Insights from housing retrofits in the United Kingdom. Energy Research and Social Science, 63. https://doi.org/10.1016/j.erss.2019.101386
Broers, W., Kemp, R., Vasseur, V., Abujidi, N., & Vroon, Z. (2022). Justice in social housing: Towards a people-centred energy renovation process. Energy Research and Social Science, 88. https://doi.org/10.1016/j.erss.2022.102527
Boess, S. (2022). Let’s Get Sociotechnical: A Design Perspective on Zero Energy Renovations. Urban Planning, 7(2), 97–107. https://doi.org/10.17645/up.v7i2.5107
Femenías, P., Mjörnell, K., & Thuvander, L. (2018). Rethinking deep renovation: The perspective of rental housing in Sweden. Journal of Cleaner Production, 195, 1457–1467. https://doi.org/10.1016/j.jclepro.2017.12.282
Garnier, S., Pittini, A., del Pero, C., & Vallan, A. (2020). HEART D9.9 - Evaluation of building users’ acceptance and satisfaction - I.
Gianfrate, V., Piccardo, C., Longo, D., & Giachetta, A. (2017). Rethinking social housing: Behavioural patterns and technological innovations. Sustainable Cities and Society, 33, 102–112. https://doi.org/10.1016/j.scs.2017.05.015
Institute for Sustainability, & UCL Energy Institute. (2012). Retrofit strategies. Key Findings: Retrofit project team perspectives. https://www.instituteforsustainability.co.uk/uploads/File/2236_KeySummary03.pdf
Lowe, R., Chiu, L. F., & Oreszczyn, T. (2018). Socio-technical case study method in building performance evaluation. Building Research and Information, 46(5), 469–484. https://doi.org/10.1080/09613218.2017.1361275
McCarron, B., Meng, X., & Colclough, S. (2019). A pilot study of radon levels in certified passive house buildings. Building Services Engineering Research and Technology, 40(3), 296–304. https://doi.org/10.1177/0143624418822444
Outcault, S., Sanguinetti, A., Dessouky, N., & Magaña, C. (2022). Occupant Non-Energy Impact Identification Framework: A human-centered approach to understanding residential energy retrofits. Energy and Buildings, 263, 112054. https://doi.org/10.1016/j.enbuild.2022.112054
Sojkova, K., Volf, M., Lupisek, A., Bolliger, R., & Vachal, T. (2019). Selection of favourable concept of energy retrofitting solution for social housing in the Czech Republic based on economic parameters, greenhouse gases, and primary energy consumption. Sustainability (Switzerland), 11(22). https://doi.org/10.3390/su11226482
Sunikka-Blank, M., Galvin, R., & Behar, C. (2018). Harnessing social class, taste and gender for more effective policies. Building Research and Information, 46(1), 114–126. https://doi.org/10.1080/09613218.2017.1356129
Traynor, J. (2019). ENERPHIT: A step by step guide to low energy retrofit. RIBA Publishing.
Walker, S. L., Lowery, D., & Theobald, K. (2014). Low-carbon retrofits in social housing: Interaction with occupant behaviour. Energy Research and Social Science, 2, 102–114. https://doi.org/10.1016/j.erss.2014.04.004
Zahiri, S., & Elsharkawy, H. (2018). Towards energy-efficient retrofit of council housing in London: Assessing the impact of occupancy and energy-use patterns on building performance. Energy and Buildings, 174, 672–681. https://doi.org/10.1016/j.enbuild.2018.07.010
Zoonnekindt, K. (2019). DREEAM scaling energy renovation: Final analysis on the tenants engagement and communication strategies 4.8. https://dreeam.eu/wp-content/uploads/2020/09/D.4.8_Final-analysis-on-tenants-engagement-and-communication-strategies-compressed.pdf
Created on 20-09-2022 | Update on 23-10-2024
Related definitions
Housing Retrofit
Area: Design, planning and building
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).
Created on 16-02-2022 | Update on 23-10-2024
Read more ->Participatory Approaches
Area: Community participation
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).
Created on 17-02-2022 | Update on 23-10-2024
Read more ->Energy Retrofit
Area: Design, planning and building
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).
Created on 23-05-2022 | Update on 23-10-2024
Read more ->Just Transition
Area: Policy and financing
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.
Created on 03-06-2022 | Update on 23-10-2024
Read more ->Social Sustainability
Area: Community participation
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.
Created on 03-06-2022 | Update on 23-10-2024
Read more ->Sustainability
Area: Community participation
Sustainability is primarily defined as 'the idea that goods and services should be produced in ways that do not use resources that cannot be replaced and that do not damage the environment' (Cambridge Advanced Learner’s Dictionary & Thesaurus, n.d.) and is often used interchangeably with the term “sustainable development”(Aras & Crowther, 2009). As defined by the UN, sustainable development is the effort to “meet the needs of the present without compromising the ability of future generations to meet their own needs” (United Nations, 1987) and is often interpreted as the strategies adopted towards sustainability with the latter being the overall goal/vision (Diesendorf, 2000). Both of these relatively general and often ambiguous terms have been a focal point for the past 20 years for researchers, policy makers, corporations as well as local communities, and activist groups, among others, (Purvis et al., 2019).
The ambiguity and vagueness that characterise both of these terms have contributed to their leap into the global mainstream as well as the broad political consensus regarding their value and significance (Mebratu, 1998; Purvis et al., 2019), rendering them one of the dominant discourses in environmental, socio-political and economic issues (Tulloch, 2013). It is, however, highly contested whether their institutionalisation is a positive development. Tulloch, and Tulloch & Nielson (2013; 2014) argue that these terms -as they are currently understood- are the outcome of the “[colonisation of] environmentalist thought and action” which, during the 1960s and 1970s, argued that economic growth and ecological sustainability within the capitalist system were contradictory pursuits. This “colonisation” resulted in the disempowerment of such discourses and their subsequent “[subordination] to neoliberal hegemony” (Tulloch & Neilson, 2014, p. 26). Thus, sustainability and sustainable development, when articulated within neoliberalism, not only reinforce such disempowerment, through practices such as greenwashing, but also fail to address the intrinsic issues of a system that operates on, safeguards, and prioritises economic profit over social and ecological well-being (Jakobsen, 2022).
Murray Bookchin (1982), in “The Ecology of Freedom” contends that social and environmental issues are profoundly entangled, and their origin can be traced to the notions of hierarchy and domination. Bookchin perceives the exploitative relationship with nature as a direct outcome of the development of hierarchies within early human societies and their proliferation ever since. In order to re-radicalise sustainability, we need to undertake the utopian task of revisiting our intra-relating, breaking down these hierarchical relations, and re-stitching our social fabric. The intra-relating between and within the molecules of a society (i.e. the different communities it consists of) determines how sustainability is understood and practised (or performed), both within these communities and within the society they form. In other words, a reconfigured, non-hierarchical, non-dominating intra-relationship is the element that can allow for an equitable, long-term setting for human activity in symbiosis with nature (Dempsey et al., 2011, p. 290).
By encouraging, striving for, and providing the necessary space for all voices to be heard, for friction and empathy to occur, the aforementioned long-term setting for human activity based on a non-hierarchical, non-dominating intra-relating is strengthened, which augments the need for various forms of community participation in decision-making, from consulting to controlling. From the standpoint of spatial design and architecture, community participation is already acknowledged as being of inherent value in empowering communities (Jenkins & Forsyth, 2009), while inclusion in all facets of creation, and community control in management and maintenance can improve well-being and social reproduction (Newton & Rocco, 2022; Turner, 1982).
However, much like sustainability, community participation has been co-opted by the neoliberal hegemony; often used as a “front” for legitimising political agendas or as panacea to all design problems, community participation has been heavily losing its significance as a force of social change (Smith & Iversen, 2018), thus becoming a depoliticised, romanticised prop. Marcus Miessen (2011) has developed a critical standpoint towards what is being labelled as participation; instead of a systematic effort to find common ground and/or reach consensus, participation through a cross-benching approach could be a way to create enclaves of disruption, i.e. processes where hierarchy and power relations are questioned, design becomes post-consensual spatial agency and participation turns into a fertile ground for internal struggle and contestation.
Through this cross-benching premise, community participation is transformed into a re-politicised spatial force. In this context, design serves as a tool of expressing new imaginaries that stand against the reproduction of the neoliberal spatial discourse. Thus, sustainability through community participation could be defined as the politicised effort to question, deconstruct and dismantle the concept of dominance by reconfiguring the process of intra-relating between humans and non-humans alike.
Created on 08-06-2022 | Update on 23-10-2024
Read more ->Social Housing
Area: Policy and financing
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).
Created on 17-06-2023 | Update on 23-10-2024
Read more ->Techno-optimism
Area: Design, planning and building
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.
Created on 14-10-2024 | Update on 07-11-2024
Read more ->Thermal Insulation & Airtightness
Area: Design, planning and building
Increasing the thermal properties of the building envelope is a passive strategy to reduce energy loss and ensure significant reductions in energy demand (Grecchi, 2022). Van den Brom et al (2019) define thermal renovation as “renovation measures that are taken to reduce energy consumption used for thermal comfort”, and group thermal insulation, airtightness and efficient electrical system into a single category. Accordingly, deep ‘thermal’ renovation occurs when significant improvement in at least three building components bring thermal performance to a level equal to or higher than the current building regulation standards (van den Brom et al., 2019). These building components include roof insulation, floor insulation, façade insulation, window improvements, heating system, domestic hot water system, and ventilation system (van den Brom et al., 2019). Other authors (Institute for Sustainability & UCL Energy Institute, 2012; Sojkova et al., 2019; Traynor, 2019) divide electrical systems into a further category for clearer practical application.
The concept of airtightness is revered for saving energy, avoiding structural damage, contributing to thermal comfort (Bastian et al., 2022), and is key to reducing heat loss through ventilation (Roberts, 2008). Draught proofing involves draught-stripping, replacing leaky windows and closing off unused chimneys (Roberts, 2008). The location of an airtight layer should be identified, and all penetrations through it minimised, sealed, and recorded (Traynor, 2019). This airtight layer can be airtight board, a plastered wall, or a membrane with appropriate tape at all junctions such as window openings (Traynor, 2019). Triple-glazed windows in combination with any frame material are the most efficient glazing system at reducing primary energy cost and CO₂ emissions (Sojkova et al., 2019). All air pockets should be sealed to prevent draughts and thermal bridging. Thermal bridging should be eliminated wherever possible, although a comprehensive thermal reduction with low internal surface temperatures can prevent physical problems such as moisture and mould (Bastian et al., 2022).
There are many forms of insulation to consider during retrofit that considerably contribute to a reduction in heat loss. Filling external cavity walls with insulation can reduce heat loss through walls by up to 40% (Roberts, 2008). Ground floor insulation and roof insulation are also necessary steps in DER (Grecchi, 2022; Roberts, 2008; Traynor, 2019). Ground floor insulation can occur in suspended timber floors between joists or above solid concrete floors (Traynor, 2019). Roof insulation can be added between structural elements, or using a ‘cold’ roof solution, with insulation laid or sprayed over the existing ceiling (Traynor, 2019). Alternatively, green roofs can reduce the amount of heat penetration through roofs, playing a similar role to roof insulation. This is done by absorbing heat into their thermal mass alongside the evaporation of moisture but will require structural upgrades to manage the new load (Roberts, 2008).
External wall insulation (EWI) protects the building fabric, improves airtightness and is relatively quick and easy to install (Roberts, 2008). EWI can also help mitigate overheating by absorbing less heat than the original material, while allowing existing thermal mass from solid masonry walls and concrete to be retained within the insulated envelope (Bastian et al., 2022). The two main external insulation systems are ventilated rainscreen systems and rendered insulation systems (Roberts, 2008). EWI is inappropriate for historical building use because it will cover the historical architectural character. Gupta & Gregg’s (2015) preserved the original exterior façade by using internal wall insulation inside the front façade and EWI on all other façades. However, drawbacks to this solution can include the loss of internal floor area, and reduced energy efficiency as notable heat loss can occur where the internal insulated wall meets the external insulated wall (Gupta & Gregg, 2015).
Created on 25-10-2024 | Update on 08-11-2024
Read more ->Related cases
Knight’s Walk (Lambeth's Homes)
Created on 26-07-2024
The review of this case study is structured to address aspects of architectural design, construction approach, and sustainability integration. The analysis draws on a range of data sources, including project design and access statements, sustainability statements, design drawings, planning applications, associated communications and archival records obtained from the planners, public records and the London Borough of Lambeth planning portal.
1. Design statement
The project site stretches to approximately 0.86 hectares, 84 residential units at a density of 215 dwellings per hectare are planned to be housed on the site. The surrounding areas are characterised by the prevalence of historic conservation areas. The site is located on the western side of the Cotton Garden Estate and is known for its public park and distinctive 22-storey Ebenezer, Hurley and Fairford towers. To the north is the Walcot Road Conservation Area with its three-storey terraced houses. To the east is Renfrew Roadside, which contains several listed buildings, including the Magistrates Court, the former Lambeth Fire Station and Workhouse (later converted to Lambeth Hospital) and what is now The Cinema Museum (Mae, 2017). Figure 1 illustrates the location of the project within the urban fabric of London.
In response to the unique characteristics and features of the site, the design team developed a comprehensive strategy to integrate the development. Firstly, the scale and massing have been carefully balanced in order to harmonize with the surrounding area. This is achieved through the use of graduated massing and a deliberate emphasis on the incorporation of open spaces and parks (Mae, 2017). Secondly, the existing transport and vehicular access has been maintained to avoid creating new routes. Thirdly, a car-free zone has been established, with the number of parking spaces on the site limited to eight, exclusively for residential units. Additionally, a number of bicycle parking bays have been installed to provide secure and convenient storage for cyclists. Fourthly, the "The Walk" concept has been implemented, offering a pedestrian route designed with human needs in mind, in an aim to promote connectivity between the site, parks, buildings, and existing public areas. This includes creating gateways and landmarks to enhance the sense of procession along the footpaths. Moreover, a balanced integration of soft and hard landscape elements was pursued to foster a sense of cohesive connectivity while preserving the site's architectural heritage (Mae, 2017). Figure 2 provides a comparative visual representation of the former site against the proposed design. Figure 2 provides a comparative visual representation of the former site against the proposed design for Knight’s Walk.
From a typological perspective, a total of 84 units have been developed, ranging in size from 54 square metres for the smallest units to 90 square metres for the largest. Phase one comprises 16 flats, including 10 one-bedroom flats, three two-bedroom flats and three three-bedroom flats. In contrast, phase two offers a broader choice with 15 one-bedroom flats, 38 two-bedroom flats and 15 three-bedroom flats.
With regard to architectural design, three key design considerations were identified as being of particular importance (HDA, 2022; Mae, 2017). The primary concern was the accessibility of the site for its residents, with particular attention paid to the needs of senior citizens and those with special requirements. This emphasis is particularly pronounced in Phase One, where the majority of units have been designed to meet both the Building Regulations Part M (which provides guidance on access to and use of buildings, including facilities for disabled occupants and easy movement through a building), and the prescribed national standards for accessible spaces (Mae, 2017). Secondly, the efficient use of space was prioritised, with the use of simple and clean architectural lines to optimise the functionality within each unit and the circulation areas. Thirdly, the well-being of residents was a significant consideration, with each unit featuring a terrace overlooking the surrounding green spaces and parks. The overall distribution of flats in both phases is shown in Figure 3.
2. Construction
In terms of construction methods, the project adopts a fabric-first approach that focuses on improving the properties of the building fabric, with the objective of optimising thermal performance, airtightness and moisture management. This approach is intended to reduce the necessity for additional mechanical or technical solutions, thereby achieving enhanced energy efficiency and comfort (Eyre et al., 2023). In addition, project planners have incorporated supplementary measures to improve construction processes (Mae, 2017). These include using a reinforced concrete structure in locations prone to thermal bridging, while avoiding cores as the primary structural support system. Furthermore, a strategy to rationalise the building’s "form factor" ensures a coherent visual progression of the building mass whilst mitigating thermal impacts such as overheating on the overall building envelope. Secondly, a balanced glazing ratio has been implemented to reduce direct thermal impacts, with the additional benefit of providing resistance to thermal mass. The use of light-coloured materials also serves to reduce the heat island effect and thermal conductivity between the exterior and interior of the building. Finally, the use of a cantilevered method, particularly in building extensions, reduces thermal bridging while improving the overall aesthetics of the structures.
3. Sustainability and energy
Several methods to promote sustainability have been integrated into the building’s envelope. The project follows the three-point model known as the "energy hierarchy", which is based on the principles of "Be Lean", "Be Clean", and "Be Green". “Be Lean” emphasizes the planning and construction of buildings that consume less energy. "Be Clean" focuses on efficiently providing and consuming energy, while "Be Green" aims to meet energy needs through renewable sources (Muralidharan, 2021).
3.1. Energy and carbon strategy
In line with energy hierarchy models, the project's energy strategy focuses on the building envelope and incorporates high-performance standards recommended by Passivhaus to optimise building mass and thermal boundaries. In addition, provisions have been made to future-proof the buildings by providing provisional spaces for future connection to planned district and central heating systems. Efforts to reduce carbon emissions centre on establishing accurate baseline emissions using the Standard Assessment Procedure (SAP), implementing passive measures such as natural ventilation and high-efficiency appliances, and reducing reliance on fossil fuels for electricity generation through the use of photovoltaic cells as a secondary energy source. As a result, the buildings have achieved a 35 per cent reduction in carbon emissions compared to local regulations and similar developments (Mae, 2017; TGA, 2017).
3.2. Overheating strategy
Managing the risk of overheating has become an essential consideration in the design and construction of housing in the UK (Sameni et al., 2015). The quality of the indoor environment in any dwelling, particularly in summer, is vulnerable to excessive solar heat gain which is accentuated by the lack of rapid ventilation measures. To mitigate these challenges, the project's overheating strategy minimises internal heat generation through energy-efficient design and reduces heat gain through careful orientation, shading, windows, and insulation. Passive ventilation measures, such as natural cross-ventilation and fixed external shading, are also utilised. In addition, primary heating pipework is carefully planned to minimise losses, particularly when installed within the dwellings (TGA, 2017).
3.3. Policy and standards
The project has been developed in accordance with a complex network of interrelated policies and standards at the national, regional and local levels, in addition to mandatory national sustainability guidelines. Notably, Building Regulations Part L, which sets out specific requirements for insulation, heating systems, ventilation and fuel use, and aim to reduce carbon emissions by 31 per cent compared to those of previous regulations. Knight's Walk introduced a new layer of mandatory requirements, designated as "regional" guidelines. These guidelines are specific to the Greater London area and serve as a reference for all developments. In addition to fulfilling the national and regional regulations, the project had to comply with the requirements set forth by the local councils. Furthermore, the developer's requirements, known as Lambeth's Housing Design Standards function as a clarifying framework, outlining the pertinent policies at the national and regional levels.
As a result, the project has comfortably achieved an energy rating of B (based on the Standards Assessment Procedure calculations), with the potential to progress to an A rating. The project has developed a multi-level sustainability strategy and architectural language that considers climate, environment, and local needs, focusing on energy and carbon reduction. These strategies include encouraging active travel, increasing biodiversity and implementing adaptations to mitigate the effects of climate change through a drainage strategy and incorporating SuDS and tree planting. In addition, each flat has been fitted with mechanical ventilation with heat recovery, providing a constant supply of fresh, filtered air even when the windows are closed. All apartments are also equipped with energy-saving electrification systems to minimise electricity consumption (HDA, 2022).
4. Reflections
The section highlights both the successful aspects and the potential areas for improvement identified in the previous sections by addressing the following questions:
What methodologies were deployed within Knight’s Walk that can be classified as exemplifying ‘good’ practise?
The comprehensive assessments conducted by the designers, covering a wide range of intervention areas, facilitated the formulation of a responsible phasing strategy that mitigated the social, economic, and environmental risks associated with large-scale development projects. The early provision of alternative, well-built housing for tenants who were displaced has fostered robust collaboration between developers, designers, and local communities.
The project was developed in accordance with widely recognised accessibility standards, including compliance with Building Regulations Part M. A comprehensive assessment framework was employed to measure the quality of outcomes in line with national, regional, and local policies. In order to facilitate the adoption of improved energy efficiency strategies, consultation was undertaken with specialists versed in Passivhaus design standards. As a result of this consultation, it was determined that no additional standards were required. These strategies included the implementation of passive measures, such as massing, orientation, and material selection, complemented by high-efficiency mechanical ventilation systems, photovoltaic cells, energy-efficient appliances and well-insulated façade designs. As a result, the project achieved a Class B environmental performance during the operational phase and a diminished average national CO₂ emission for residential buildings by 80 per cent. The project's carbon production averaged 0.7 tonnes of CO₂ per year, with primary energy consumption ranging from 42 to 58 kilowatt hours per square metre (kWh/m2) (DLUHC, 2021).
What are the potential weaknesses inherent to Knight’s Walk?
Notwithstanding the robust practices that were put in place, several risks were identified, particularly in relation to the design approach that was selected. Although the fabric-first approach is regarded as a fundamental tenet of sustainable construction, it has not been without its detractors. A significant concern is the long-term variability in the performance of fabric-first buildings, which is contingent upon factors such as maintenance practices, occupant behaviour and climate fluctuations. Inadequate construction quality or maintenance practices can result in the deterioration of energy efficiency gains over time, underscoring the need for continuous monitoring and maintenance (Eyre et al., 2023). This could consequently result in a considerable increase in operational costs, thereby jeopardising the objective of housing affordability over the long term. Furthermore, buildings with high insulation using the fabric-first approach may be susceptible to overheating during the warmer seasons in certain climates, particularly if passive cooling strategies are inadequately integrated into the design (Eyre et al., 2023). This can lead to additional energy consumption for cooling purposes and counteract efforts to achieve highly efficient energy.
