1. Introduction
Society will not meet crucial net zero greenhouse gas (GHG) emission goals without achieving deep-energy retrofits for all residential buildings. Yet, building retrofits to increase energy efficiency and enable decarbonization have been difficult to implement effectively (Mata et al. 2021). They have been a particularly challenging climate solution to implement despite the fact that they can realize GHG emission reductions more quickly, are cost-effective compared with other climate change-mitigation actions, and can be achieved using existing technologies (Hoicka & Das 2021). A better understanding of how to effectively pursue deep-energy retrofits is needed, especially as numerous known barriers make retrofits challenging to implement (Hoicka & Das 2021; Tozer 2019).
Deep-energy retrofits for residential buildings are an opportunity to address energy poverty. Energy poverty is when households experience inadequate access to energy services such as heating or lighting sufficient to live a decent life (Middlemiss 2022). Linking deep-energy retrofits with energy poverty is a matter of justice since energy-poor households are often entangled in other socio-economic adversities that restrict their abilities to mitigate and/or adapt to a changing climate. The energy poor must be:
able to participate in the transition to net zero, and […] not subject to further disadvantage through it.
Energy poverty has a range of social and health impacts and has been linked to health conditions such as cardiovascular disease and respiratory conditions (Marmot Review Team 2011). Deep-energy retrofits can address energy poverty by reducing energy waste, reducing monthly household bills, and improving thermal comfort of homes (Hoicka & Das 2021; Zhivov et al. 2015). While there have been reviews summarizing the enablers of retrofits generally (Mata et al. 2021), behavioral barriers to climate change mitigation in energy-poor households (Streimikiene et al. 2020), and the relationship between energy poverty and health (Ballesteros-Arjona et al. 2022), there remains a lack of research focused on the barriers and enablers of retrofit implementation that are specific to households vulnerable to energy poverty.
This paper answers the question: Which factors have been identified as influencing the achievement of low-carbon energy retrofits for households vulnerable to energy poverty? The paper is structured as follows. First, the significance of deep retrofits for energy poverty is explained. Next, the methods for this systematic literature review are introduced. The findings are then presented, which identify a range of influential factors across several themes: financial, policy and organizational, trust and communication, technical, attitudes and values, and health, safety, and comfort. Policy recommendations and conclusions are made.
2. Energy retrofits to address energy poverty
2.1 What is energy poverty?
Energy poverty—sometimes referred to as fuel poverty or energy insecurity—is broadly understood as the lack of adequate energy services to provide basic needs (Harrison & Popke 2011; Reames 2016). Though energy poverty is difficult to define due to objective and subjective indicators (Martini 2021), as well as differences in geographical location (Liu et al. 2019), some of the most commonly identified drivers of energy poverty are poor energy efficiency, low incomes, and high energy bills, in addition to political, structural, and situational drivers such as the 2022 ‘gas crisis’ (Boardman 1991; Middlemiss 2022). Energy poverty is measured and identified across scales from the household level—e.g. households that would need to spend more than 10% of their income to achieve adequate heating (Boardman 1991)—to national measures of the share of households with an absolute energy expenditure below half of the national median or the share of households in a nation who self-report an inability to keep the home warm (Martini 2021).
Geographical differences in climate impact households’ vulnerability to energy poverty by determining temperature variations and how challenging it is to maintain thermal comfort affordably (Middlemiss 2022). The state of building infrastructure impacts energy poverty, since the presence of heating and cooling infrastructure, amount of insulation, and condition of buildings can either exacerbate or mediate the effects of extreme temperatures on inhabitants (Middlemiss 2022). In addition, social and political factors such as the labor market, the state of social policies, and the housing and energy markets influence energy poverty by impacting peoples’ costs of living and abilities to earn a living wage (Middlemiss 2022). Higher inequality and levels of absolute poverty are also correlated with higher levels of energy poverty (Galvin 2019).
Households experiencing energy poverty tend to sacrifice other needs in order to pay for their energy supply, exacerbating other social issues related to poverty such as lower educational attainment (Xu & Chen 2019). Energy poverty is also linked to physical and mental health issues such as cardiovascular disease, respiratory conditions, anxiety and depression, and increased risk of conditions, e.g. influenza, pneumonia, asthma, arthritis, and accidents at home (Marmot Review Team 2011).
2.2 How can deep energy retrofits impact energy poverty?
Deep-energy retrofits are major building renovations that reduce energy-use intensity by at least 50% relative to a pre-renovation baseline and also provide associated improvements in the quality and comfort of the indoor environment (Zhivov et al. 2015). Deep-energy retrofits provide energy-use-intensity (energy efficiency) improvements through means including insulation, air-sealing, and new windows and doors. These energy efficiency improvements allow households to use less energy to achieve the same levels of energy service (Xu & Chen 2019). Deep-energy retrofits are often linked to GHG emission-reduction goals and can include fuel-switching away from fossil fuel-powered heating and cooling.
For energy-poor households, deep-energy retrofits can ameliorate one of the primary drivers of energy poverty, which is energy inefficiency or leakiness (Middlemiss 2022; Martini 2021). Deep retrofits sometimes reduce post-retrofit energy expenditures, which can allow households to adequately meet their energy needs within their financial means (Harrison & Popke 2011; Hernández & Bird 2010). These energy and cost savings can also improve household resilience to increases in energy costs (Hoicka & Das 2021). Regardless of reduced energy costs, the indoor environmental quality and comfort improvements associated with deep-energy retrofits can improve overall quality of life for households experiencing energy poverty (Harrison & Popke 2011; Hernández & Bird 2010). However, energy retrofits can also worsen energy poverty if they are implemented in a way that does not protect housing affordability and security. Deep-energy retrofits can lead to instances of ‘renoviction’ in rental properties, where value-added renovations cause the displacement of tenants through forced evictions or increases in rent (Bouzarovski et al. 2018).
3. Methods
A systematic literature review was conducted to assess the state of knowledge on the barriers to energy efficiency retrofits in the context of households vulnerable to energy poverty. The articles analysed in this study were obtained from the Scopus and Web of Science databases using a keyword search under the default search settings. These databases were chosen because they are large, interdisciplinary databases that are commonly used to conduct reviews in this field. No date, geography, discipline, or other restrictions were applied to the database searches.
One keyword search string was used to search both Web of Science and Scopus:
‘public accept*’ OR ‘social accept*’ OR ‘market accept*’ OR ‘adoption’ OR willingness OR diffusion OR ‘decision making’ OR preference* OR barrier* OR constrain* OR obstacl* OR obstruct* OR problem OR enabl* OR facilitat*
AND
energ* OR efficien* OR ‘low carbon’ OR decarboniz* OR decarbonis* OR climat* OR emission* OR carbon
AND
retrofit* OR renovat* OR ‘energy efficiency retrofit’ OR ‘passive hous*’ OR ‘passive design’ OR ‘insulat*’ OR envelop* OR refurbish* OR ‘thermal comfort’ OR weatheriz*
AND
building* OR commercial* OR residential* OR house OR home
AND
equity OR ‘low income’ OR ‘energy poverty’ OR ‘energy burden’ OR ‘energy insecurity’ OR ‘social housing’ OR ‘public housing’ OR ‘fuel poverty’ OR ‘energy vulnerability’
The results from the keyword searches in Scopus and Web of Science were imported into the web-based systematic review program Covidence for screening on 10 and 16 November 2021, respectively. Figure 1 demonstrates the number of papers included and excluded at each stage of screening. A total of 316 articles were imported from Scopus, and 315 from Web of Science, for a total of 631 articles. Duplicates were removed leaving 463 papers to be screened.
Figure 1
Workflow chart for selecting articles suitable for a systematic review of energy efficiency retrofits in households vulnerable to energy poverty.
Sources: Adapted from Mata et al. (2021) and Page et al. (2021).
First, a title and abstract screen was completed. Papers were only included if their titles and abstracts indicated that they had a clear focus on low income, energy insecure, or energy-poor households and/or social/public housing, and that they had findings directly related to barriers, enablers, or influencing factors for actual retrofit projects. Non-peer-reviewed sources, sources written in languages other than English, and sources to which the authors could not gain access were also excluded at this stage. A total of 365 articles were excluded during the title and abstract screening.
A total of 98 articles remained for the full text screening phase, of which five could not be retrieved in full. The same criteria used in the title and abstract screening were applied in the full text screening. A total of 59 articles were excluded during full-text screening, of which 30 were removed due to a lack of focus on retrofit implementation, 23 were removed for lack of empirical insight (modelling only), and six were removed due to a lack of focus on low income or energy poverty. At the conclusion of both screening stages, 34 articles remained included. Three additional articles were added to the pool based on the authors’ discretion, leading to a total of 37 articles included in the analysis. The list of the articles in this analysis is provided in supplemental data online.
Each article was analyzed by the first author, while 10% of the articles were analyzed by each of the other two authors for the purpose of cross-checking analysis. Data were extracted from each paper relating to the building typologies, demographics and market segments of focus, the type of retrofits described, the methodological approaches, the geographical coverages of the studies, and the barriers and enablers to retrofits identified.
The extracted data were entered into a qualitative analysis table, using both a deductive and an inductive approach to systematically analyze findings on barriers and enablers to retrofit. The deductive approach involved the use of the categories from the summary table of reasons for adoption of low carbon solutions from Mata et al. (2021), which was augmented with new categories based on an inductive approach. Analysis of this table was performed to identify the most prominent and important themes in the factors influencing the achievement of energy retrofits unique to the demographic included in the study.
4. Results
4.1 Summary of the articles reviewed
This subsection first summarizes the articles included in this review in terms of geography, date, and types of retrofit activities. Most articles had a geographical focus on the UK, with only two articles focused on a geographical context outside Europe and North America (Table 1). The geographical distribution of articles—as determined by the continent of the first author’s institution—was similarly concentrated on Europe and North America (Table 2). The articles included in the review were all published between 2004 and 2021, with the majority of articles published within or since 2018 (Figure 2).
Table 1
Geographical coverage by country of the content of articles included in the systematic review of energy efficiency retrofits in households vulnerable to energy poverty.
| GEOGRAPHICAL COVERAGE OF ARTICLE BY COUNTRY | COUNT |
|---|---|
| Brazil | 1 |
| UK | 17 |
| France | 1 |
| The Netherlands | 5 |
| Canada | 2 |
| Australia | 1 |
| Italy | 1 |
| United States | 3 |
| Austria | 1 |
| Lithuania | 1 |
| Ireland | 2 |
| Poland | 1 |
| Multiple European Union countries | 1 |
Table 2
Continent of the first author’s institution of articles included in the systematic review of energy efficiency retrofits in households vulnerable to energy poverty.
| CONTINENT OF THE FIRST AUTHOR’S INSTITUTION | COUNT |
|---|---|
| Europe | 31 |
| North America | 5 |
| Australia/Oceania | 1 |
Figure 2
Distribution of year of publication of articles included in the systematic review of energy efficiency retrofits in households vulnerable to energy poverty.
Energy efficiency retrofit activities described in the articles included: insulation (wall, attic/loft, and/or ceiling), window and door replacement, air-sealing, light fixture replacement, improved or decarbonized heating and cooling, and renewable energy generation. Some articles described only one or two of these activities, although most of the articles described a combination of multiple retrofit activities. A few articles did not specify what was done and only referred to energy efficiency retrofit activities broadly.
4.2 Factors that enable and constrain retrofits
Specific factors were categorized that enable and constrain retrofits for households vulnerable to energy poverty. The themes that emerged are financial, policy and organizational, trust and communication, technical, attitudes and values, and health, safety and comfort.
4.2.1 Financial factors
Retrofit costs are a key consideration for property owners and tenants. Government-supported programs offering energy efficiency retrofits that reduce or eliminate retrofit costs to property owners and tenants while also leading to future energy savings are effective at enabling retrofit adoption (Long et al. 2015). The adoption of retrofit often stemmed from government support and state subsidies, particularly in the context of social housing (Hoppe 2012; Prati et al. 2020; Reeves 2011), though these are particularly successful as part of a suite of policy instruments (Tsenkova 2018). Social housing landlords identify government funding as important for retrofits both for financial viability (Cauvain & Karvonen 2018; Liu 2018), but also to raise the profile of retrofit projects internally to secure budgeting and resources (Hoppe 2012; Liu et al. 2019).
Some property owners are motivated by an expectation that retrofits will reduce maintenance costs (Liu 2018; Peel et al. 2020; Prati et al. 2020), maintain property value (Liu 2018; Prati et al. 2020), and reduce vacancy and/or rent arrears (Liu 2018; Peel et al. 2020). Tools such as discount incentives for landlords (Reames 2016), negative gearing for tax subsidies (Liu et al. 2019), and community-based approaches emphasizing the cost-effectiveness of retrofits (Putnam & Brown 2021) have been found to encourage the participation of landlords in retrofit programs. Financial benefit to tenants, particularly those in fuel poverty, motivates social housing providers to pursue retrofits (Lambrechts et al. 2021; Liu 2018; Swan et al. 2013). A study of social housing providers in the UK found that social housing providers align:
various agendas, including safeguarding the wellbeing of tenants, ensuring the future viability of social housing sector, planning for rising energy costs, anticipating future CO2 regulations, and addressing tenant expectations for more optimal building performance.
Homeowners and tenants are also motivated by finances. Tenants of social housing are motivated to support energy retrofit programs due to opportunities to save on energy costs (Liu 2018; Prati et al. 2020; Streimikiene & Balezentis 2020). While some studies found that quality of life and health improvements were the dominant motivating factors for residents to support retrofits (Elsharkawy & Rutherford 2018; Lilley et al. 2017), others found that retrofit adoption by homeowners in lower income brackets are strongly motivated by decreases to monthly energy costs, followed by a desire to have a warmer house and reduce mold, while those in higher brackets are motivated by increases in property value (Long et al. 2015). Retrofits can be paid for using a variety of methods, which tenants and homeowners support to varying degrees (Seebauer 2021; Streimikiene & Balezentis 2020; MacDonald et al. 2020).
The high initial costs for retrofits and lack of sufficient funding streams were found to be a barrier across many of the studies (Bodach & Hamhaber 2010; Streimikiene & Balezentis 2020; Swan et al. 2013). High investment costs are particularly a barrier for low-income households with high energy costs (Charlier 2015) and low-income households expressed a reluctance to take on a loan (Streimikiene & Balezentis 2020). Paradoxically, the increasing costs of energy make the high investment costs for retrofits even more of a barrier; while a retrofit would pay itself off faster, lower income households have difficulty accessing the finances that would be needed for the initial investment since day-to-day costs are already squeezed by high energy costs (Liu et al. 2019; MacDonald et al. 2020). Some studies found that social housing providers found retrofit interventions too expensive to broadly apply across their building portfolios (Lambrechts et al. 2021; Reeves 2011; Tsenkova 2018).
Rent and energy cost impacts can be a barrier. Tenants can reject or feel negatively about retrofits due to concerns about cost impacts, which includes rent increases but also maintenance and other costs (Brown et al. 2014; Hoppe 2012; Ossokina et al. 2021; Reeves 2011). There is evidence that tenants are sometimes skeptical about rent increases and resistant to retrofit schemes where rents would increase, even if decreases in energy costs are anticipated to leave them with lower monthly costs overall (Hoppe 2012; Ossokina et al. 2021; Reeves 2011). Another issue related to cost impacts is the perceived fairness and clarity of different ways of splitting the costs of retrofits (Bright et al. 2019; Webb et al. 2016). Tenants may resist retrofits if they fear that costs and benefits will be unequally or unfairly shared (Hoppe 2012). If residents in multi-unit buildings share electricity meters or if rents are set inclusive of energy utilities, there is no incentive for individual units to conserve energy (Bodach & Hamhaber 2010; Tsenkova 2018). Renters may want to make efficiency upgrades, but do not have the authority (Liu et al. 2019) or may not expect to stay long enough to reap the benefit of reduced energy bills (Charlier 2015).
4.2.2. Policy and organizational factors
The literature describes a retrofit enabling factor that is summarized here as organizational leadership. Referred to as organizational commitment (Swan et al. 2013), project leadership (Hoppe 2012), or institutional capacity (Tsenkova 2018), this enabling factor refers to the ability to effectively plan and perform retrofit activities. Retrofits are more successful when project management approaches take advantage of opportunities for:
economies of scale, ‘one-stop shop’ approach and enhanced accountability for planning, financing and monitoring of projects
and residents are motivated to participate in retrofits when there is a person or institution to bear the organizational costs (Streimikiene & Balezentis 2020). Learning through practice enables retrofits by social housing authorities (Hughes et al. 2020; Lambrechts et al. 2021; Lowery et al. 2012; Peel et al. 2020). Organizational leadership can also be delivered through community-led approaches, which have been found to be:
effective at engaging households, can contribute to local supply chain development, help households access financing, and be a valuable delivery partner for local authority fuel poverty schemes.
In addition, retrofits are effectively enabled by government requirements (Lambrechts et al. 2021; Liu 2018; Reeves 2011; Tsenkova 2018). Notably, the perception that policy is coming can also be a driver for building owners to pursue retrofits (Reeves 2011; Cauvain & Karvonen 2018). A lack of government support and institutional barriers make it difficult to navigate retrofit policies, particularly a lack of consistency in government policy (Lambrechts et al. 2021; Peel et al. 2020; Putnam & Brown 2021). While this is a common finding for retrofits, a more nuanced finding specifically for low-income households is that government policies on energy poverty have not supported retrofits. Policies have focused on cost relief on an emergency basis for low-income households and there is a lack of government support for programs that pay for energy efficiency improvements in low-income households (Liu et al. 2019).
Retrofits are hindered by poor communication, complex program design and delivery, and lack of capacity. There are issues with communication, such as across government agencies to scale-up retrofits or to pursue integrated retrofits (e.g. energy, aging in place, and health) (Hughes et al. 2020; Rodger et al. 2021). Complexities in program design and delivery can also be a challenge for retrofits, such as high administrative burden for subsidy applicants (Fylan et al. 2016; Lambrechts et al. 2021). Retrofits often take place alongside other repairs or property improvements and program rules that make pursuing joint repairs difficult are a barrier (Reames 2016). In addition, abrupt changes to government funding rules can derail retrofits and reduce trust in future government programs (Fylan et al. 2016; Liu 2018).
4.2.3. Communication and trust
Communication before, during, and after the retrofit process garnered tenants’ support for energy retrofits, while trust enhanced this support. Poor communication and engagement with tenants are a barrier to retrofit (Brown et al. 2014; Sunikka 2006). Communication and engagement can enhance initial support for retrofits by shrinking the information gap to make eligible households aware of retrofit support programs. This communication can be successful through multimodal engagement such as energy efficiency labeling for buildings (Bodach & Hamhaber 2010), information on bills, or leaflets emphasizing the relevance to people‘s lives (Brown et al. 2014; Liu et al. 2019). A focus on co-benefits can help here:
unless a direct connection was made between residents’ social and economic priorities and weatherisation, it would be difficult to motivate a large number of households to participate.
Communication and engagement during the implementation of retrofits is also important. Studies find that when tenants are involved and well informed about key aspects of the project, they are more supportive (Prati et al. 2020). One study found that:
low-income renters welcome a wide range of procedural options, in particular, providing transparent and comprehensive information on the planned renovation and mitigating inconvenience during the construction phase.
It is effective to emphasize outcomes such as increased comfort (Ossokina et al. 2021) or quality-of-life improvements and gradually introduce environmental outcomes (Reames 2016). In addition, poor understanding of the purpose of retrofits can cause homeowners to abandon the process after application to a program (Pillai et al. 2021).
Trust is a crucial factor driving the adoption of retrofits and can even be generated through successful retrofit projects. First, it is important that residents obtain information about retrofit programs from sources they trust (Liu et al. 2019; MacDonald et al. 2020). In a retrofit program targeting a specific low-income neighborhood in the US, staff used community-based social marketing approaches to drive participation by having trusted members of the community share good experiences about the program and advocate for weatherization in their own neighborhoods (Reames 2016). Trust is eroded if residents feel:
disenfranchised from the process, rather than ownership of it [… or] like subjects in an experiment that they had not consented to.
A direct contact for residents who worked to resolve problems was a solution in these cases (Webb et al. 2016). Barriers can also arise due to trust concerns about the acceptance of outsiders or concerns about unknown contractors in their homes (Brown et al. 2014; Reames 2016).
Trust between residents and landlords is also influential. When occupants have higher trust of their landlords, they are more likely to endorse payment schemes that distribute costs among residents based on ability to pay or using green lease schemes:
presumably because they are confident that their interests will be heard when ability criteria and payment schemes are defined.
Successful retrofit experiences beget trust (Long et al. 2015), but tenants and building owners may also have mistrust based on experiences with previous repairs or modernization that has had cost overruns or has been promised but delayed or not delivered (Brown et al. 2014; Hoppe 2012; Prati et al. 2020). Households may distrust the government and distrust programs promising renewal after years of broken promises (Reames 2016). Residents may not trust that participation in the program is in their best interest if they feel like they will be penalized for seeking funding (Reames 2016). Finally, a lack of trust can be a barrier particularly when it is transmitted between residents, including through myths (e.g. tenants are not eligible, there will be a hidden charge on utilities bills, etc.) (Brown et al. 2014).
4.2.4 Technical
Retrofits are motivated by the need to replace or improve a building’s technical facilities. Building owners identify opportunities for retrofits by surveying stock conditions (e.g. equipment energy ratings or replacement cycles, insulation type, etc.) and, in line with a long-term strategy, efficiency projects may be chosen. Tenants are supportive of retrofits aligned with planned renewal (Ossokina et al. 2021: 10).
Program eligibility can be difficult to navigate due to the condition of existing technical elements of the building and the narrow eligibility pathway that must be navigated for some programs. Programs might exclude buildings that have had some weatherization, even if more is needed (Reames 2016), or might require homes to be in good condition by requiring that programs only pay for efficiency improvements. The age and condition of the building stock can affect retrofit success (Peel et al. 2020; Pillai et al. 2021). Social housing providers may need to navigate trade-offs between replacing essential building components and energy-efficiency retrofits since there is sometimes not enough funding to do both (Tsenkova 2018).
4.2.5. Information
Information barriers include the poor quality of energy performance data, poor resident awareness of retrofit programs, and a lack of professional advice. Accurate energy performance data can be challenging to obtain, making it difficult to communicate anticipated outcomes to residents and achieve specific energy-use reductions (Bright et al. 2019; Lowery et al. 2012). Awareness about existing programs is an issue (Elsharkawy & Rutherford 2018; Healy & Clinch 2004; Reames 2016). Community-led approaches can help to target and engage lower income households (Putnam & Brown 2021; Reames 2016). Private landlords can be difficult to identify and contact to engage in programs (Fylan et al. 2016). The provision of information after retrofits is another challenge; residents are dissatisfied with retrofits if they do not know how to operate, maintain, or monitor new systems, and new systems may not operate correctly (Bal et al. 2021; Fylan et al. 2016; Lilley et al. 2017; Sunikka-Blank et al. 2012). Finally, studies show a lack of awareness and training about efficiency retrofits in general in the construction sector (Bodach & Hamhaber 2010; Lambrechts et al. 2021) and point to insufficient energy related advice received in order to plan retrofit projects (Elsharkawy & Rutherford 2018).
4.2.6 Attitudes and values
Social housing providers can be morally motivated to pursue retrofits to provide affordable housing, but environmental, financial, and social values also jointly play a role in the adoption of energy efficiency retrofits for social housing (Cauvain & Karvonen 2018; Lambrechts et al. 2021; Liu 2018; Reeves 2011). Environmental values also played a role as a co-benefit along with addressing social and economic priorities (Prati et al. 2020; Reames 2016; Reeves 2011). Finally, efficiency measures that improve aesthetic appearance also motivate retrofits (Bal et al. 2021; Bright et al. 2019; Lilley et al. 2017; Prati et al. 2020).
Resistance to new technology can also be a barrier. Tenants may be familiar with certain energy technologies and fear or dislike change (Hoppe 2012; Sunikka 2006). Staff of social housing providers can also be skeptical of new technology based on past experiences (Reeves 2011).
4.2.7 Health, safety, and comfort
Retrofits were enabled by the possibilities for improved comfort as well as improved health and safety. The outcome of achieving a warmer home motivates occupants to pursue retrofits (Bright et al. 2019; Elsharkawy & Rutherford 2018; Lilley et al. 2017; Webb et al. 2016) and has even been heralded as the ‘most significant outcome’ of retrofits (Elsharkawy & Rutherford 2018: 302). For example:
in homes that were previously considered hard to heat and where some occupants reported that they felt they were never warm enough, tenants considered this improvement in thermal comfort to be more significant than money saving.
Comfort levels can improve significantly. For one retrofit:
the proportion who said cold housing was a ‘serious’ problem fell to one-third of previous levels.
(Webb et al. 2016): 420
Occupants have been found to support retrofits with combined health and comfort benefits (Lilley et al. 2017; Long et al. 2015; Ossokina et al. 2021; Prati et al. 2020; Baborska-Narozny et al. 2020). The inability to afford adequate heating and cooling is not just an issue of comfort since fuel poverty has health implications such as respiratory and cardiovascular illnesses. Energy cost savings after retrofits may be used to address these health, safety, and comfort issues (Elsharkawy & Rutherford 2018). Quality-of-life concerns can take precedence over financial savings, even for low-income households (Lilley et al. 2017). Nonetheless, residents are concerned about discomfort during the retrofit period (Brown et al. 2014; Long et al. 2015; Peel et al. 2020; Sunikka-Blank & Galvin 2021). Concerns about discomfort during the retrofit period shape people’s decisions about whether or not to pursue a retrofit (Brown et al. 2014; Long et al. 2015).
5. Discussion
This paper reviewed evidence about the factors that affect the realization of retrofits for households in energy poverty. Similarities to general findings on retrofits were compared with findings specifically related to households in energy poverty. Some of the findings relate to the household itself (e.g. factors influencing support for retrofits by tenants) and some relate to landlords or building owners (e.g. factors enabling social housing providers to retrofit).
Financial factors are important in the consideration of energy retrofits for low-income households, which is consistent with previous findings (Bodach & Hamhaber 2010; Lang et al. 2021; Mata et al. 2021; Peel et al. 2020; Streimikiene & Balezentis 2020; Swan et al. 2013; Bal et al. 2021). Previous work on barriers and enablers of retrofits has mainly focused on upfront costs without identifying the nuanced impacts on other financial considerations (Lang et al. 2021; Mata et al. 2021). The findings of this review highlight the importance of understanding retrofits in the context of their holistic financial impacts on residents and building owners in terms of upfront costs, rent, maintenance, and energy expenses. First, no-cost retrofit options are motivating factors for low-income residents (Long et al. 2015). In addition, lower costs for landlords to participate in retrofit programs reduces barriers to participation. Also, there is evidence that renters are not only motivated to support retrofit programs by the prospect of lower energy costs, but also by the related (perceived or real) impacts on their other expenses, such as rent and maintenance. Lastly, another financially motivating factor for landlords and social housing providers of affordable housing is the expectation of having lower vacancy, rent arrears, and maintenance costs (Liu 2018; Peel et al. 2020; Prati et al. 2020).
While financial factors are certainly critical in retrofit decisions, it is found here that comfort, health, and quality-of-life considerations are of equal or greater importance in the decision-making of both low-income households and rental building owners (Bal et al. 2021; Elsharkawy & Rutherford 2018; Lilley et al. 2017; Ossokina et al. 2021; Reames 2016). These findings specific to households vulnerable to energy poverty contrast with much of the retrofit literature, which highlights financial factors as the most salient barrier (Alam et al. 2019; Mata et al. 2021). In addition, general literature on retrofits frequently discuss ‘comfort’ as a motivating factor (Beillan et al. 2011; Lang et al. 2021; Leardini et al. 2015), but it is found that for households vulnerable to energy poverty, the importance of retrofits extends beyond comfort and into health. Many of the studies included in this review cited the desire to establish warmer, healthier homes free of dampness and mold as a motivating factor in retrofit decisions (Bright et al. 2019; Lilley et al. 2017; Long et al. 2015; Ossokina et al. 2021; Prati et al. 2020).
Health and energy poverty alleviation considerations have been found to be particularly motivating for social housing providers, whose moral mandates drive them to pursue retrofits for the benefit of their tenants, beyond the pursuit of financial gain (Bright et al. 2019; Cauvain & Karvonen 2018; Reeves 2011). These findings are consistent with the growing field of literature on the impacts energy poverty and health, which finds that living in energy poverty is associated with conditions such as respiratory and cardiovascular illness (Cai et al. 2020; Elsharkawy & Rutherford 2018), poor self-reported health, poor mental health (Thomson et al. 2017), and the exacerbation of existing conditions (Marmot Review Team 2011).
This review also identified national and local government requirements to pursue retrofits as a motivating factor in the decision to retrofit, particularly within the social housing sector (Lambrechts et al. 2021; Liu et al. 2019; Liu 2018; Peel et al. 2020; Reeves 2011; Tsenkova 2018). Prior research has identified the importance of government subsidies and consistent and supportive government policy in retrofit implementation (Alam et al. 2019; Butt et al. 2021; Lang et al. 2021; Mata et al. 2021), which were also found to be motivating factors in this review (Lambrechts et al. 2021; Liu et al. 2019; Liu 2018; Peel et al. 2020; Reeves 2011). The present findings show that requirements to complete retrofits through regulations or policy targets have been influential, which is a step beyond enabling policies such as subsidies.
It was also found that trust and communication are important enablers of successful retrofit implementation. There is a clear need for trust and communication between residents and housing providers (both social and private) regarding retrofit measures and costs (Reames 2016; Seebauer 2021), between housing providers and governments regarding policies, regulation, and funding (Hoppe 2012; Lambrechts et al. 2021), and between residents/building owners and practitioners (Brown et al. 2014; Hoppe 2012; Prati et al. 2020). Further, there are many dimensions of trust that are specifically important to households vulnerable to energy poverty, as this demographic has often experienced broken promises on the part of governments and housing providers, social inequities, and disenfranchisement from decision-making, which means that trusted messengers are particularly important (Reames 2016; Webb et al. 2016; Putnam & Brown 2021). The present findings support other research identifying lack of trust as a barrier (Mata et al. 2021) while highlighting the importance of communication from trusted sources and the necessity of building trust through procedural transparency and reciprocity before, during, and after retrofit implementation, especially among residents who are vulnerable to energy poverty.
6. Policy recommendations
Based on the barriers and enablers identified by the literature reviewed in this study, key recommendations are identified for retrofit policies targeted at households vulnerable to energy poverty (Table 3).
Table 3
Policy recommendations for retrofit policies targeted at households vulnerable to energy poverty
| RECOMMENDATIONS FOR RETROFIT POLICIES TARGETED AT HOUSEHOLDS VULNERABLE TO ENERGY POVERTY | KEY SOURCES |
|---|---|
| Hoppe (2012); Ossokina et al. (2021); Reames (2016); Reeves (2011); Baborska-Narozny et al. (2020) |
| Hughes et al. (2020); Prati et al. (2020); Seebauer (2021); Bal et al. (2021) |
| Reames (2016); Putnam & Brown (2021) |
| Elsharkawy & Rutherford (2018); Friedman (2010); Howden-Chapman et al. (2005); Nicol et al. (2015); Cauvain & Karvonen (2018) |
| Lambrechts et al. (2021); Liu (2018); Reeves (2011); Tsenkova (2018) |
| Bright et al. (2019); Lowery et al. (2012) |
7. Conclusions
This systematic review has identified which factors influence the achievement of energy retrofits for households vulnerable to energy poverty. The results identify a range of influential factors across several themes: financial, policy and organizational, trust and communication, technical, attitudes and values, and health. Health and quality of life are particularly influential motivating factors among households vulnerable to energy poverty. This is notable since the retrofit literature frequently discusses comfort as a motivating factor but does not extend further to identify health. The findings also show the importance of trust and communication between stakeholders. Multiple financial considerations are also important, such as the availability of no-cost retrofit options and the prospect of lower energy and maintenance costs, and government requirements to retrofit and minimum energy standards are motivating.
Further research on energy efficiency retrofit implementation in households vulnerable to energy poverty is required. First, the findings of this review are based on papers with an extremely limited geography, with the majority of studies originating in the UK. Further research is needed across different geographical contexts to gain a better understanding in the context of different demographics, climates, housing types, and political and social structures. Second, there is an opportunity to connect the literature on the factors producing vulnerability to energy poverty—a literature that is outside of the purview of this review—with the enablers and barriers of retrofits. For example, are some barriers to retrofits greater for specific groups (e.g. older people)? Lastly, the studies within this review predominately focus on social housing, leaving a gap in research on retrofits in low-income private rental and low-income ownership situations. This gap is important to address, as there are many non-social housing households that are vulnerable to energy poverty.
Acknowledgements
The authors thank the reviewers for their helpful and insightful comments.
Competing interests
The authors have no competing interests.
Funding
This research was funded by a University of Toronto Scarborough Cluster of Scholarly Prominence grant entitled ‘Urban Just Transitions from Scarborough to the Globe.’
Supplemental data
Supplemental data for this article can be accessed at: https://doi.org/10.5334/bc.304.s1