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Pre-1919 Niddrie Road Retrofit – An Example of Care for Climate and Health

Created on 06-11-2023 | Updated on 13-11-2023

Some 73,000 dwellings, which account for one-fifth of the city housing stock in Glasgow, are pre-1919 sandstone tenements. Unfortunately, these historic buildings frequently face issues related to poor energy efficiency, primarily caused by outdated windows and air leakage from the façade to indoor spaces. These buildings' construction, design, and materials pose a significant challenge for the city in achieving its net-zero emission targets for its housing stock. Glasgow must reduce emissions resulting from energy consumption while simultaneously improving residents' comfort levels.


This case study highlights a deep retrofit project of an empty traditional Scottish tenement block in Glasgow. The retrofit adopted the Passivhaus enerPHit standard to address critical housing challenges, such as energy efficiency, inadequate insulation, poor indoor air quality, and the health implications of ageing homes. The project resulted in renovating eight one-bedroom flats within a classic tenement building on 107 Niddrie Road in Strathbungo East, on the city's south side.


Despite challenges related to building orientation and structural issues, this historic sandstone building became the first in Scotland to meet the Passivhaus enerPHit standard. As a result, it now offers energy-efficient, well-ventilated flats for eight households. This case study demonstrates that even century-old buildings can outperform new constructions regarding energy efficiency while simultaneously addressing environmental and societal concerns. Its success yields valuable lessons and sets a promising example for similar renovation projects in Scotland and regions with comparable climates.


The retrofitting project, led by the Southside Housing Association with support from the Scottish Government and Glasgow City Council, has gained international recognition. It was displayed in COP26's virtual pavilion as a prime example of "Deep-carbon refurbs for hard-to-heat and hard-to-treat tenement homes". It received the Glasgow Institute of Architects Sustainability Award for 2022.

John Gilbert Architects -

107 Niddrie Road, Govanhill, Glasgow

Project (year)

Construction (year)

Housing type

Urban context
City Center

Construction system

Building renovation

Reference documents

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Report from the UK Collaborative Centre for Housing Evidence "Niddrie Road, Glasgow: Tenement Retrofit Evaluation". It presents the research evaluation and broader lessons for tenements and old housing stock.



The term 'retrofit' remains a subject of debate, often used interchangeably with 'refurbishment' and 'renovation', lacking a clear distinction. Linguistically, the Oxford English Dictionary (2023) defines 'retrofit' as:

"A modification made to a product or structure to incorporate changes and developments introduced since manufacture or construction; the action or fact of modifying a product or structure in this manner. Also figurative. Concerning buildings, in later use, often implying (an instance of) the making of adaptations to improve energy efficiency or to counteract or mitigate the effects of climate change."
For buildings, retrofit encompasses substantial physical modifications made to them. These changes can stem from two kinds of activities: mitigating activities aimed at improving energy efficiency and adaptive activities, often referred to as 'adaption', involving interventions such as adjustments, reuse or upgrades to align the building with new requirements or conditions  (Dixon, 2014).

The retrofitting process of this old tenement at 107 Niddrie Road involved activities for various purposes. For instance, external activities included preserving the aesthetic appearance and heritage of Glasgow's iconic housing typology. The internal activities included repairing all services, including urgent maintenance for timber elements and structural enhancements for future residents' safety.

The retrofitting decisions were also made as a response to the pressing demands of climate change and the future needs of residents. However, these decisions were primarily based on the expertise of the landlord (the housing association), architects, and the Passivhaus enerPHit standard rather than the active involvement of the future occupants (see RE-DWELL blogpost Retrofit and Social Engagement). 

In this case study, we will only focus on three primary goals of the retrofitting process: low energy consumption, low carbon emissions, and ensuring the health and wellbeing of future dwellers.


Low energy consumption

The 107 Niddrie Road is an example of how to tackle fuel poverty among dwellers living in this type of historic housing stock. In Scotland, approximately 30% of families living in traditional tenements (equivalent to 175,000 homes) are considered to be fuel poor. The substandard housing conditions of old tenements make it challenging to maintain indoor warmth. Consequently, a substantial portion of a family's income is allocated to energy bills, exacerbating fuel poverty.

The retrofit involved implementing several energy measures aligned with the Passivhaus enerPhit standard to enhance the tenement's energy efficiency. The architects of John Gilbert expect these measures to result in slashing heating costs by up to 90%. Therefore, this retrofit can be considered a deep energy retrofit. Deep energy retrofit provides up to 60 % energy savings by upgrading the building using "a combination or "package" of multiple energy measures that upgrade the physical fabric, heat generation system and lighting of a building" (Page 3, Saffari & Beagon, 2022). The adopted energy measures for this deep energy retrofit included:

1) Retrofitting the fabric:  It involved insulating walls, roof, and ground floor, installing triple-glazed windows, and ensuring airtightness to minimise thermal bridging. The retrofit also guaranteed a continuous airtightness line, including all key junctions at the attic level, windows, and doors.

2) Use of Waste Water Heat Recovery (WWHR) system:  This system heats cold water using heat recovered from shower or bath drain water. This method significantly reduces hot water costs and carbon emissions by approximately 40%. Given that heating water represents the second largest cost of a fuel bill, this system is expected to substantially reduce these costs and carbon emissions.

3) Individual Air Source Heat Pumps (ASHP):  These units were installed in the four flats on the lower floors. In parallel, efficient combi gas boilers were set up in the remaining flats to compare their performance with ASHP during residents' occupancy.


Low carbon emissions

Various measures, including the installation of ASHP and WWHR systems and the utilisation of natural materials, were implemented in a bid to reduce carbon emissions and combat climate change. The project minimised its environmental impact using fewer new materials than new construction blocks. The UK Collaborative Centre for Housing Evidence is currently evaluating the extent of the carbon reduction achieved through these measures.


Ensuring health and wellbeing

By adopting the Passivhaus enerPHit standard, the project prioritised occupant comfort, indoor air quality, and energy efficiency. Expected benefits include:

1) Thermal comfort and reduced energy costs: The retrofit project aimed to maintain warmth during winter and coolness in summer, thereby reducing energy costs, improving residents' quality of life, and minimising temperature-related stress amid rising energy expenses and extreme temperature fluctuations.

2) Damp and mould mitigation for indoor air quality:  Condensation and humid air are common issues in Scottish homes, often leading to dampness and mould, adversely affecting residents' health. The project implemented the following techniques to mitigate these risks:

  • Improving ventilation: A high-performance Mechanical Ventilation Heat Recovery (MVHR) system was installed to provide constant fresh air while extracting humidity. Contrary to a common misconception that installing MVHR eliminates the need to open windows, it is possible to do so in moderation, particularly during extreme temperatures, to conserve energy.
  • Ensuring air tightness: Thermal bridges, which leak heat during winter and create cold spots on walls, were eliminated. The retrofit assured continuous airtightness line.
  • Using breathable materials: Lime plaster was used for airtightness and vapour-permeable wood fibre for insulation. These materials mitigate common moisture-related risks in highly airtight buildings.

3) Reduced toxicity of materials for indoor air quality: Efforts were made to minimise indoor air pollution by opting for natural building materials wherever feasible. These materials were chosen to uphold excellent indoor air quality and reduce low-level toxins that could exacerbate health problems, especially for vulnerable individuals. Additionally, chemical treatments on wood were avoided to limit exposure to harmful substances and reduce costs.

4) Altered layout for better functionality and accessibility: Major changes were made to make dwellings more functional for households and guests. Some of the changes contributed to optimising available space, demonstrating the adaptability of the existing property. These adjustments aimed to improve accessibility while complying with current building regulations. A comparison of the before and after floor plan images reveals two main differences. Firstly, the kitchen was relocated closer to the living room area; it was distant and only accessible through the bedroom, making it impractical. Secondly, the bathroom was redesigned to accommodate a spacious shower, and the toilet was moved from the end of a long and narrow corridor. This change ensured accessibility, especially for family members using a wheelchair.

5) Preserve the tenement heritage: The street-facing facade was internally insulated, ensuring the building's historic appearance was preserved. Additionally, triple-glazed windows were carefully chosen to keep the traditional window frame design.


Replicating this retrofitting process on a large scale

The retrofit project at 107 Niddrie Road represents a noteworthy example of successfully implementing the Passivhaus enerPHit standard for deep retrofitting old tenements. The retrofit incorporated a range of energy efficiency techniques, including enhanced ventilation systems and the use of natural, non-toxic materials. However, replicating these retrofits on a larger scale presents some advantages and challenges. For instance, retrofitting several tenements at once could offer the financial benefit of bulk purchasing advanced energy-efficient technologies, like heat pumps, potentially reducing overall costs.

However, the social factor of the dwellers poses a challenge in replicating these projects on a larger scale, mainly when dealing with multiple tenements being retrofitted simultaneously.

Minimising disruptions to residents' daily lives during work is imperative to ensure the success of building retrofitting. In inhabited properties, resident cooperation becomes pivotal for project success. Resistance or a lack of understanding among residents can impede the implementation process. Retrofritting an inhabited dwelling disturbs household life. Communicating the benefits of the retrofit project and addressing residents' concerns becomes paramount, which is also time-consuming and financially burdensome for housing associations. Therefore, a critical factor that contributed to the successful process of executing the retrofit in this case was the vacant status of the flats, which might not be the case for other Scottish tenements.

Retrofitting tenements on a large scale faces several technical challenges, including the absence of a dependable supply chain for advanced technologies like heat pumps. Some technologies mandated by the Passivhaus standards are relatively new to the UK market. Additionally, the technical expertise required to install and maintain these advanced technologies is still inadequate.

Alignment with project research areas

The 107 Niddrie Road project, as an example of deep retrofitting, addresses some issues within the three primary research areas of RE-DWELL.

Design, Planning and Building

This project aimed to serve as a model for the Scottish housing system by showcasing the potential of retrofitting a 120-year-old tenement. It demonstrates the feasibility of retrofitting vacant and abandoned homes and promotes energy and carbon savings. Furthermore, it highlights the retrofit's potential to enhance health and wellbeing by reducing energy costs, ensuring year-round ventilation, mitigating dampness and mould, and avoiding toxic materials. Despite the inherent challenges in heating tenements, the project provides valuable lessons and inspires confidence for future retrofitting endeavours. It should encourage planning authorities to adopt similar healthy and low-carbon home retrofitting approaches.

Community Participation

During the retrofitting process, residents were not actively involved because the building had been vacant for two years due to safety concerns related to its structural stability. However, in the future, residents will play an active role on a personal level, contributing to using low-carbon homes and evaluating their performance. A comprehensive research project led by the UK Collaborative Centre for Housing Evidence (CaCHE) at the University of Glasgow will assess the performance and costs of two groups of flats. Planned monitoring systems will collect real-time data from one group with installed heat pumps and compare it to the group of flats with gas boilers. This extensive monitoring and tenant engagement approach aims to identify areas that require communication and determine the necessary support for tenants to optimise the use of their new energy-efficient homes.

Policy and Financing

The retrofitted flats will be offered as social housing rentals. The project's objective is to provide affordable housing and combat fuel poverty. It surpasses government energy efficiency standards, alleviating the financial strain on tenants related to energy bills. This initiative is expected to decrease instances of rent defaults and vacant properties, making housing more affordable in terms of both rent and energy costs.

The project offers valuable insights into both policy and finance, with funding contributions from Glasgow City Council, the Southside Housing Association (property owners), and the Scottish Government. A research partnership has been established to investigate the retrofitted tenement further. CaCHE is leading the research at the University of Glasgow in collaboration with Prof Tim Sharpe from the University of Strathclyde Department of Architecture, Chris Morgan from John Gilbert Architects, Glasgow City Council, and CCG Construction Ltd.

This retrofitting project and the associated research serve as a compelling case study for policymakers as it underscores the potential of retrofitting vacant housing to reduce embodied carbon and energy consumption. Furthermore, it enables a comparison of the costs and efficiency of various heating systems, offering valuable insights for decarbonisation initiatives.


Design, planning and building

Community participation

Policy and financing

* This diagram is for illustrative purposes only based on the author’s interpretation of the above case study

Alignment with SDGs

The project supports various Sustainable Development Goals (SDGs), with elaboration on seven of them as follows:

SDG 3: Good health and wellbeing

The project prioritised the health and wellbeing of households, implementing various measures aligned with the EnerPHit standard. These efforts included repairing the fabric to ensure adequate insulation and airtightness, providing warmth in winter. Measures also aimed at enhancing indoor air quality by installing MVHR systems to maintain year-round ventilation to mitigate mould and dampness and using non-toxic materials. Reducing heating demands was an integral step to lowering energy bills to be paid by occupants. Moreover, the exterior facade was meticulously repaired, preserving the place's heritage and distinctive Scottish spirit.


SDG 7: Affordable and Clean Energy

The project aimed to retrofit this tenement to be energy-efficient by using ASHP and WWHR, in addition to enhancing the performance of the building envelope. As a result, energy bills for the residents are expected to drop significantly, making the housing more affordable. As a result, the project contributes substantially to addressing challenges related to fuel poverty.


SDG 9: Industry, Innovation, and Infrastructure

If the housing stock is considered an integral component of national infrastructure, Glasgow, for example, boasts a significant inventory of 73,000 historic pre-1919 sandstone tenements. This endeavour is noteworthy in tackling challenges associated with this prevalent housing type within the city. It stands as an innovative, collaborative effort between housing-related industries and institutions aiming to retrofit historical buildings using techniques that respond to current and future needs related to climate change mitigation and the impact of energy price fluctuations while caring for residents' health in the long term.


SDG 10: Reduced Inequalities

This project has transformed eight social housing flats into energy-efficient, renovated, and healthy living spaces. The implemented energy efficiency measures not only exceeded government standards and social landlord requirements but also significantly reduced energy bills, alleviating the financial burden of the tenants. This cost reduction could lead to decreased rent defaults and vacant properties, thereby enhancing the availability and affordability of decent housing. Ultimately, it promotes equal opportunities for individuals to reside in comfortable, well-maintained homes.


SDG 11: Sustainable cities and communities

The retrofitting process embodies various facets of sustainability. Firstly, it addresses economic sustainability by lowering energy bills for residents. Secondly, the decisions prioritise low embodied carbon, contributing to environmental sustainability. Additionally, the project focuses on the health and wellbeing of residents. Transforming these tenements into high-performance social housing reflects a commitment to social sustainability.


SDG 13: Climate Action

The project recognises the environmental and social costs of neglecting climate change and fuel poverty. In doing so, it addresses several key themes, highlighting a pioneering approach to energy efficiency that reduces carbon footprint and ensures the building's resilience during temperature fluctuations. This project was selected as a best practice case study for the virtual pavilion, exemplifying the initiatives implemented in Glasgow, the COP26 host city.


SDG 17: Partnerships for the Goals

The project brought together diverse stakeholders, including housing associations, local government, academia, and industry experts to collaborate in addressing climate change while prioritising household wellbeing. Monitoring systems were installed to provide real-time data for researchers to compare the operational performance and costs between heat pumps and gas boilers as heating systems, contributing to the ongoing discussions about fuel cost and fuel poverty. This partnership with academia for the real-time evaluation of the flats' performance underscores the significance of working together to achieve sustainable objectives for this tenement and future initiatives.


Retrofitting Niddrie Road: the pre-1919 tenement undergoing a 21st century revamp. (2021). Scottish Housing News. Retrieved from:  (Accessed: 11 September 2023)

Niddrie Road Retrofit (n.d.) John Gillbert Architects. Retrieved from: (Accessed: 7 September 2023)

Fearn, H. (2014) If housing were seen as infrastructure there would be a lot more of it, The Guardian. Retrieved from: (Accessed: 12 September 2023).

International Passive House Association (2023) frequently asked questions with regard to Passive Houses. Available at: https://www.passivehouse (Accessed: 12 September 2023)

Scottish Ecological Design Assosiation (2023) The Sustainable Renovation design guideline. Available at



Virtual Tour: COP26 Virtual Tour inside the 107 Niddrie Road building before retrofitting:

You Tube Video: Niddrie Road: A blueprint for energy-efficient traditional tenements?

You Tube Video: Niddrie Road Virtual Visit with John Gilbert Architects (09/08/2022) | streamed by  The Glasgow Institute of Architects explaining various technical details to overcome issues of executing proper insulation and airtightness in this historic building:

You Tube Video: Virtuous Luxury: How Passive Houses can improve life and help the Planet | Jeff Colley | TEDxTralee

BBC Article on this project: How do we make homes fit for net zeroes?


Related vocabulary

Energy Poverty

Energy Retrofit

Housing Retrofit

Area: Policy and financing

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

Created on 17-10-2023

Author: T.Croon (ESR11)


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

Author: S.Furman (ESR2)


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

Author: A.Fernandez (ESR12), Z.Tzika (ESR10), S.Furman (ESR2)


Related publications

Furman, S. (2022, August). Upgrading social housing to meet the socio‐economic needs of today’s dwellers, and the environmental needs of the planet: A framework beyond retrofit. In New Housing Researchers Colloquium (NHRC) at the European Network for Housing Research (ENHR) Conference 2022, Barcelona, Spain.

Posted on 30-08-2022




Icon retrofit-and-social-engagement-we-can-do-better

Retrofit and Social Engagement | We can do better

Posted on 13-07-2023

That’s it. The final summer school of RE-DWELL has officially been and gone. This year saw input not only from my cohort of ESRs and supervisors, but we were joined by industry partners to test the first iteration of RE-DWELL’s ‘Serious Game’ – which will be coming to a city near you. ‘Serious Game’ combines academia and industry to help all housing stakeholders navigate complex questions regarding holistically sustainable housing. Through the game, transdisciplinary discussion promptsaction through tools and methods within policy and finance; design, planning and building; and community participation – the benchmark of RE-DWELLS investigations. This output will form a part of the transdisciplinary framework based on the ESR’s PhD’s.   One turn of the 'Serious Game' took our group from the solution “new tools to tailor make housing solutions”—through exploring methods including urban rooms, workshops with critical action research, transdisciplinary collaboration, and grant of use models—to an answer: “could the participation of people living in social housing improve retrofit solutions more than end point performance targeted retrofit?” Funnily enough, this question is identical to one of my research questions.   Working on my PhD in social housing retrofit with tenant engagement, has put the terms “retrofit” and “social sustainability” on the tip of my tongue. Constantly ready to listen, learn, and discuss these concepts, I see blind spots everywhere. Tom Dollard from Pollard Thomas Edwards revealed a stunning environmentally sustainable scheme, even attempting some socially sustainable effort on the Blenheim Estate greenfield site in Oxfordshire but drew attention to the ethical grey area of building on a greenfield. Paul Quinn from Clarion revealed plans for regeneration that prioritise the Right-to-Return but is often not taken advantage of. A good way to keep the existing community together, Quinn says, is to build new environmentally sustainable housing on the same plot, decant the existing tenants into this housing, then retrofit the rest. Of course, this only works if the plot allows new buildings, and often buildings with retrofit potential are still cited for demolition and rebuild.   85-95% (European Commission, 2020) of buildings will remain standing in 2050, in the UK this extends to 80% of all dwellings (Pierpoint et al., n.d.) and they desperately need retrofitting for the climate crisis and for inhabitants. There are residential buildings in London designed for 40% occupancy. These leave 60% of those homes empty, acting as safety deposit boxes called “foreign investment”. Do we need to build more? Or do we need to re-enforce existing building stock and insist on full occupancy? When asked about retrofit, “we could do better” is a common reply from architects and housing associations. So why aren’t we doing better? It’s true that retrofit incurs more upfront cost that new build—in part because new build in the UK is exempt from tax, while retrofit is not—but the opportunities for long-term returns are enormous. To name a few: embodied carbon savings; new supply chains; opportunities to upskill unemployed tenants in a field with huge skills gaps; upskilling construction workers who fear a dwindling construction sector; physical and mental health and wellbeing implications; and integrative, iterative learning from the tenants who are experts in the way they live.   During the RE-DWELL visit to London, I visited the Building Centre exhibition Retrofit 23:Towards Deep Retrofit of Homes at Scale*. The exhibition (which I highly recommend) displays examples of retrofit from around the UK. The questions identified in the exhibition read “how do we fund retrofit and leverage the benefits? How best can deep retrofit be scaled up locally across streets and neighbourhoods to meet the net zero goals?”. It states that improving performance brings environmental, economic, and social benefits. Environmental benefits are easily displayed through energy performance statistics, economic benefits are displayed in terms of financial cost, but social benefits remain a struggle to translate beyond technical measures such as quantifiable indoor air quality and temperatures. The lack of quantifiable social benefits can be a huge barrier in tenant engagement because of the need to justify the extra expense, especially in social housing. But this is where engagement is most needed. In homes where residents are already disempowered by the knowledge that changes to their homes are not their decision to make. Noble efforts of community engagement displayed on a handful of case studies in the Retrofit 23 exhibition include: meetings with installers, on-site training, and one example of a resident design group where tenants had some real design impact.   Deep Retrofit comes with a specific restriction: to reduce energy consumption by 60-90% of pre-retrofit levels (Fawcett, 2014; Femenías et al., 2018) and therefore immediately places the focus on environmental sustainability and economic viability, consequently deemphasising social sustainability. So I ask the question: can deep retrofit lead to holistic sustainability? Mostly, engagement efforts are systems motivated, attempting to teach residents the correct use of technical systems, at times nominating technical agents from within the building to help transfer this knowledge to the others.   The biggest success of the Retrofit 23 exhibition must be the message board. Full of answers to the question “how can the challenge of retrofitting homes be made easier?”. Answers included: more grant money; increased low-carbon incentives; neighbourhood scale solutions; increase supply chains; increased education and training; upskill; knowledge sharing with children, schools, and communities; and attention to detail to avoid costly mistakes. My personal additions included cut tax on retrofit, extend funding spending deadlines, and legislate social engagement processes.   Often, social housing residents don’t want costly mechanical interventions, they want people to listen to their input and learn from the way they occupy their homes. Not that technical solutions don’t have their place, of course. But there are plenty of energy savings to be had with passive solutions, education, and conversation.   Let’s do better.     *Retrofit 23: Towards Deep Retrofit of Homes at Scale is a free exhibition held at the Building Centre in London until 29thSeptember 2023.     References European Commission. (2020). A Renovation Wave for Europe -greening our buildings, creating jobs, improving lives.   Fawcett, T. (2014). Exploring the time dimension of low carbon retrofit: Owner-occupied housing. Building Research and Information, 42(4), 477–488.   Femenías, P., Mjörnell, K., & Thuvander, L. (2018). Rethinking deep renovation: The perspective of rental housing in Sweden. Journal of Cleaner Production, 195, 1457–1467.   Pierpoint, D., Rickaby, P., & Hancox, S. (n.d.). Social Housing Retrofit Toolkit MODULE 3: Housing Retrofit Policy Summary.

Author: S.Furman (ESR2)

Summer schools, Reflections


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