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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).

References

Bartiaux, F., Gram-Hanssen, K., Fonseca, P., Ozoliņa, L., & Christensen, T. H. (2014). A practice-theory approach to homeowners’ energy retrofits in four European areas. Building Research and Information, 42(4), 525–538. https://doi.org/10.1080/09613218.2014.900253

Brounen, D., & Kok, N. (2011). On the economics of energy labels in the housing market. Journal of Environmental Economics and Management, 62(2), 166–179. https://doi.org/10.1016/j.jeem.2010.11.00

Cerin, P., Hassel, L. G., & Semenova, N. (2014). Energy Performance and Housing Prices. Sustainable Development, 22(6), 404–419. https://doi.org/10.1002/sd.1566

European Commission. (2021). Energy Performance of Buildings Directive. Available at: https://ec.europa.eu/energy/topics/energy-efficiency/energy-efficient-buildings/energy- performance-buildings-directive_en (Accessed: 19 ¬¬October 2021)

Fawcett, T. (2014). Exploring the time dimension of low carbon retrofit: Owner-occupied housing.

Building Research and Information, 42(4), 477–488. https://doi.org/10.1080/09613218.2013.804769

Fuerst, F., Haddad, M. F. C., & Adan, H. (2020). Is there an economic case for energy-efficient dwellings in the UK private rental market? Journal of Cleaner Production, 245. https://doi.org/10.1016/j.jclepro.2019.118642

Fuerst, F., McAllister, P., Nanda, A., & Wyatt, P. (2015). Does energy efficiency matter to home- buyers? An investigation of EPC ratings and transaction prices in England. Energy Economics, 48, 145–156. https://doi.org/10.1016/j.eneco.2014.12.012

Institute for Sustainability & UCL Energy Institute. (2012). Retrofit strategies. Key Findings: Retrofit project team perspectives.

Johnston, D., Lowe, R., & Bell, M. (2005). An exploration of the technical feasibility of achieving CO2 emission reductions in excess of 60% within the UK housing stock by the year 2050. Energy Policy, 33(13), 1643–1659. https://doi.org/10.1016/J.ENPOL.2004.02.003

Karvonen, A. (2013). Towards systemic domestic retrofit: A social practices approach. Building Research and Information, 41(5), 563–574. https://doi.org/10.1080/09613218.2013.805298

Maller, C., Horne, R., & Dalton, T. (2012). Green Renovations: Intersections of Daily Routines, Housing Aspirations and Narratives of Environmental Sustainability. 29(3), 255–275. https://doi.org/10.1080/14036096.2011.606332

Moloney, S., Horne, R. E., & Fien, J. (2010). Transitioning to low carbon communities—from behaviour change to systemic change: Lessons from Australia. Energy Policy, 38(12), 7614– 7623. https://doi.org/10.1016/J.ENPOL.2009.06.058

Ravetz, J. (2008). State of the stock—What do we know about existing buildings and their future prospects? Energy Policy, 36(12), 4462–4470. https://doi.org/10.1016/J.ENPOL.2008.09.026

Tjørring, L., & Gausset, Q. (2018). Drivers for retrofit: a sociocultural approach to houses and inhabitants. 47(4), 394–403. https://doi.org/10.1080/09613218.2018.142372

van den Brom, P., Meijer, A., & Visscher, H. (2019). Actual energy saving effects of thermal renovations in dwellings—longitudinal data analysis including building and occupant characteristics. Energy and Buildings, 182, 251–263. https://doi.org/10.1016/j.enbuild.2018.10.025

Created on 16-02-2022 | Update on 07-10-2022

Related definitions

Energy Retrofit

Author: S.Furman (ESR2)

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 20-09-2022

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Indoor Thermal Comfort

Author: S.Furman (ESR2)

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.

Created on 20-09-2022 | Update on 01-12-2023

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Life Cycle Costing

Author: A.Elghandour (ESR4)

Area: Design, planning and building

Life Cycle Costing (LCC) is a method used to estimate the overall cost of a building during its different life cycle stages, whether from cradle to grave or within a predetermined timeframe (Nucci et al., 2016; Wouterszoon Jansen et al., 2020). The Standardised Method of Life Cycle Costing (SMLCC) identifies LCC in line with the International Standard ISO 15686-5:2008 as "Methodology for the systematic economic evaluation of life cycle costs over a period of analysis, as defined in the agreed scope." (RICS, 2016). This evaluation can provide a useful breakdown of all costs associated with designing, constructing, operating, maintaining and disposing of this building (Dwaikat & Ali, 2018). Life cycle costs of an asset can be divided into two categories: (1) Initial costs, which are all the costs incurred before the occupation of the house, such as capital investment costs, purchase costs, and construction and installation costs (Goh & Sun, 2016; Kubba, 2010); (2) Future costs, which are those that occur after the occupancy phase of the dwelling. The future costs may involve operational costs, maintenance, occupancy and capital replacement (RICS, 2016). They may also include financing, resale, salvage, and end-of-life costs (Karatas & El-Rayes, 2014; Kubba, 2010; Rad et al., 2021). The costs to be included in a LCC analysis vary depending on its objective, scope and time period. Both the LCC objective and scope also determine whether the assessment will be conducted for the whole building, or for a certain building component or equipment (Liu & Qian, 2019; RICS, 2016). When LCC combines initial and future costs, it needs to consider the time value of money (Islam et al., 2015; Korpi & Ala-Risku, 2008). To do so, future costs need to be discounted to present value using what is known as "Discount Rate" (Islam et al., 2015; Korpi & Ala-Risku, 2008). LCC responds to the needs of the Architectural Engineering Construction (AEC) industry to recognise that value on the long term, as opposed to initial price, should be the focus of project financial assessments (Higham et al., 2015). LCC can be seen as a suitable management method to assess costs and available resources for housing projects, regardless of whether they are new or already exist. LCC looks beyond initial capital investment as it takes future operating and maintenance costs into account (Goh & Sun, 2016). Operating an asset over a 30-year lifespan could cost up to four times as much as the initial design and construction costs (Zanni et al., 2019). The costs associated with energy consumption often represent a large proportion of a building’s life cycle costs. For instance, the cumulative value of utility bills is almost half of the cost of a total building life cycle over a 50-year period in some countries (Ahmad & Thaheem, 2018; Inchauste et al., 2018). Prioritising initial cost reduction when selecting a design alternative, regardless of future costs, may not lead to an economically efficient building in the long run (Rad et al., 2021). LCC is a valuable appraising technique for an existing building to predict and assess "whether a project meets the client's performance requirements" (ISO, 2008). Similarly, during the design stages, LCC analysis can be applied to predict the long-term cost performance of a new building or a refurbishing project (Islam et al., 2015; RICS, 2016). Conducting LCC supports the decision-making in the design development stages has a number of benefits (Kubba, 2010). Decisions on building programme requirements, specifications, and systems can affect up to 80% of its environmental performance and operating costs (Bogenstätter, 2000; Goh & Sun, 2016). The absence of comprehensive information about the building's operational performance may result in uninformed decision-making that impacts its life cycle costs and future performance (Alsaadani & Bleil De Souza, 2018; Zanni et al., 2019). LCC can improve the selection of materials in order to reduce negative environmental impact and positively contribute to resourcing efficiency (Rad et al., 2021; Wouterszoon Jansen et al., 2020), in particular when combined with Life Cycle Assessment (LCA). LCA is concerned with the environmental aspects and impacts and the use of resources throughout a product's life cycle (ISO, 2006). Together, LCC and LCA contribute to adopt more comprehensive decisions to promote the sustainability of buildings (Kim, 2014). Therefore, both are part of the requirements of some green building certificates, such as LEED (Hajare & Elwakil, 2020).     LCC can be used to compare design, material, and/or equipment alternatives to find economically compelling solutions that respond to building performance goals, such as maximising human comfort and enhancing energy efficiency (Karatas & El-Rayes, 2014; Rad et al., 2021). Such solutions may have high initial costs but would decrease recurring future cost obligations by selecting the alternative that maximises net savings (Atmaca, 2016; Kubba, 2010; Zanni et al., 2019). LCC is particularly relevant for decisions on energy efficiency measures investments for both new buildings and building retrofitting. Such investments have been argued to be a dominant factor in lowering a building's life cycle cost (Fantozzi et al., 2019; Kazem et al., 2021). The financial effectiveness of such measures on decreasing energy-related operating costs, can be investigated using LCC analysis to compare air-condition systems, glazing options, etc. (Aktacir et al., 2006; Rad et al., 2021). Thus, LCC can be seen as a risk mitigation strategy for owners and occupants to overcome challenges associated with increasing energy prices (Kubba, 2010). The price of investing in energy-efficient measures increase over time. Therefore, LCC has the potential to significantly contribute to tackling housing affordability issues by not only making design decisions based on the building's initial costs but also its impact on future costs – for example energy bills - that will be paid by occupants (Cambier et al., 2021). The input data for a LCC analysis are useful for stakeholders involved in procurement and tendering processes as well as the long-term management of built assets (Korpi & Ala-Risku, 2008). Depending on the LCC scope, these data are extracted from information on installation, operating and maintenance costs and schedules as well as the life cycle performance and the quantity of materials, components and systems, (Goh & Sun, 2016) These information is then translated into cost data along with each element life expectancy in a typical life cycle cost plan (ISO, 2008). Such a process assists the procurement decisions whether for buildings, materials, or systems and/or hiring contractors and labour, in addition to supporting future decisions when needed (RICS, 2016). All this information can be organised using Building Information Modelling (BIM) technology (Kim, 2014; RICS, 2016). BIM is used to organise and structure building information in a digital model. In some countries, it has become mandatory that any procured project by a public sector be delivered in a BIM model to make informed decisions about that project (Government, 2012). Thus, conducting LCC aligns with the adoption purposes of BIM to facilitate the communication and  transfer of building information and data among various stakeholders (Juan & Hsing, 2017; Marzouk et al., 2018). However, conducting LCC is still challenging and not widely adopted in practice. The reliability and various formats of building related-data are some of the main barriers hindering the adoption of LCCs (Goh & Sun, 2016; Islam et al., 2015; Kehily & Underwood, 2017; Zanni et al., 2019).

Created on 05-12-2022 | Update on 20-05-2023

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Area: Policy and financing

Window guidance is a credit policy allowing central banks to steer bank lending toward certain economic activities. In the post-war period, it was common for both developed and emerging economies to employ various forms of credit control and allocation. However, these policies were virtually discontinued by the 1980s and the mandate of the central banks was reduced to controlling inflation through interest rates. Housing affordability and sustainability are strongly interlinked with monetary policies, particularly because housing prices and supply rely on debt for financing (Muellbauer, 2018). This link is embodied in inflation-adapted interest rates, which are used by central banks to “cool down” the economy and control prices. Currently, high inflation has pushed central banks all over the world to increase interest rates. Increases in interest rates impact the interbank lending rates such as the Euribor or the Libor and ultimately affect the price of credit in an economy. This then influences in particular capital-intensive industries such as housing development and renovation. Social housing organisations (SHOs) which provide social -thus affordable- rental housing, particularly in North-Western Europe, are dependent on credit to finance not only the provision of housing, but also the energy-efficient renovation of their stock. The rise in interest rates resulting from central banks’ monetary policy aimed at curbing inflation puts the financial viability of renovation and new construction in jeopardy. This insight is not new, as the dependence on credit for renovation and maintenance was already foreseen as an issue in the late 90s by the British housing economist Christine Whitehead (1999). Traditionally, governments support social housing providers through grants, subsidies and through the guaranteeing of their debt (Lawson, 2013). For example, publicly owned social housing providers in Germany have their debt rated equally to that of their main owners: municipalities and regions. As a result, their financing costs also benefit from a high rating implying low-interest rates for their debt. This is also the case in France and the Netherlands where ultimately it is public institutions that guarantee SHO debt. For instance, a Dutch social housing provider raises debt at a triple AAA rating, that of the Dutch state. This lowers their interest costs in comparison to that of other companies which may be rated lower, hence have a higher risk premium and pay more for their debt (Fernández et al., forthcoming). In an inflationary environment, where interest rates rise across the board, this means higher financing costs for SHOs despite their risk premium remaining constant. Window guidance is relevant in this context because it would allow central banks to set a lower interest rate for lending to certain activities, thus creating a window. During the period between 1945-1980, advanced and emerging economies alike implemented interventions on credit and capital markets. Central banks would align lending with industries, exports and manufacturing while increasing interest rates for less desirable sectors (Bezemer et al., 2023; Hodgman, 1973). According to Bezemer et al., (2023) based on Hodgman (1973) and Goodhart (1989 pp. 156–158), ‘credit guidance’, ‘credit controls’, ‘credit ceilings’, ‘directed credit’, and ‘moral suasion’ are also common names for these types of policy. More recently, organisations such as Positive Money have been advocating for a sovereign money proposal where banks would obtain funds from their national central bank with limitations on their usage (Youel, 2022). This enhanced control over bank lending opens up the possibility of earmarking private capital for investment in decarbonisation activities. For example, lending for speculative purposes or for highly polluting activities could be curtailed while the financial viability of environmentally friendly activities could be expanded. Ultimately, credit controls offer the possibility to guide credit toward the provision of affordable and sustainable housing and away from sectors such as fossil fuels or speculative bubbles.  

Created on 24-04-2023 | Update on 22-05-2023

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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 20-06-2023

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Performance Gap in Retrofit

Author: S.Furman (ESR2)

Area: Design, planning and building

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.

Created on 08-09-2023 | Update on 01-12-2023

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Post-occupancy Evaluation

Author: L.Ricaurte (ESR15)

Area: Design, planning and building

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.

Created on 22-10-2023 | Update on 16-11-2023

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