Analysing energy considerations in residential renovation planning and design: a case study comparison between Denmark and Sweden

The European Commission has set a goal to reduce the dependence on fossil fuels by 2050 (Tsemekidi Tzeiranaki et al., 2022). Buildings in the EU are responsible for 40% of energy use and 36% of greenhouse gas emissions (Tsemekidi Tzeiranaki et al., 2022). Approximately, 75% of the existing residential buildings in the EU are energy inefficient according to building standards (Filippidou & Jimenez Navarro, 2019) and 75%–80% of them will still be in use by the year 2050 (Fabbri et al., 2016). Approximately 97% of the existing buildings in the EU need to be upgraded by 2050 to achieve the ambitious decarbonisation and climate-neutrality goals the EU has set up for 2050 (Bean et al., 2019). Additionally, the revised Directive (EU) 2024/1275 (Energy Performance of Building Directive) (European Union, 2024) sets trajectories for progressive renovation in residential buildings, by calling the Member States to take action to reduce the average primary energy use of residential buildings by 16% in 2030 and by 20–22% in 2035, with at least 55% of that reduction to be achieved through the renovation of the 43% worst performing residential buildings. Thus, there is a need for the Member States to examine their strategies further to respond to the need for extended renovation on a massive scale.

When it comes to renovation, numerous energy efficiency and reduction measures are available; however, the building industry has been reluctant to embrace them (Butt et al., 2021; Economidou et al., 2019; Lindkvist et al., 2014; Moshood et al., 2024). It's frequently observed that technical solutions for energy efficiency in buildings are not only available and economically viable but also not consistently implemented (Cabeza & Chàfer, 2020; D'Agostino et al., 2021; Economidou et al., 2020). The discrepancy between the potential for enhancing energy efficiency and reduction and the actual outcomes is commonly termed the energy paradox (e.g., Broin et al., 2015; Gram-Hanssen, 2014; Solà et al., 2021). Moezzi and Janda (2014) further emphasise that social potential is just as crucial as technical potential. Social potential refers to the capacity of social groups and communities to contribute to energy efficiency, not just through individual behaviors but through collective actions and social interactions. It involves how groups—such as tenants, professionals, and citizens—can influence energy practices and decision-making, thereby helping drive systemic change. Unlike technical potential, which focuses on available technological solutions, social potential highlights the role of social dynamics and collective participation in shaping energy use.

This study aligns with the growing interest in exploring energy and buildings through an interpretative lens (Schweber & Leiringer, 2012; Gram-Hanssen & Georg, 2018; Hagbert & Femenias, 2016). The interpretative lens in this study is characterised by its emphasis on context, real-world practices, the dynamics of inclusion and exclusion, interdisciplinary insights, and the prioritisation of energy efficiency in decision-making processes. The focus is on meanings and contexts that shape professionals’ decisions. By focusing specifically on the planning and design meetings of building professionals, this research addresses a critical gap in understanding why energy efficiency measures are sometimes prioritised while at other times neglected. The primary research questions addressed in this article are as follows: (i) How does the focus on energy efficiency emerge as the focal point in renovation planning and design meetings, and why are they sometimes not prioritised over other concerns? (ii) In what circumstances are energy efficiency initiatives met with resistance in comparison to other agenda items, and how can this resistance be elucidated?

In response to the growing interest in energy efficiency and the building industry, this study provides a unique contribution by focusing specifically on the decision-making dynamics within renovation planning meetings, a previously underexplored area in renovation research. This emphasis on the micro-level dynamics of planning and design meetings allows us to investigate how energy efficiency measures are negotiated, prioritized, or sidelined in the context of real-world practices. Previous research by some of the authors has highlighted the role of building professionals in facilitating or hindering energy efficiency measures (Palm & Reindl, 2018; Reindl, 2017). Furthermore, they explored how energy emerges from the practices of building professionals and how energy efficiency measures evolve as these professionals negotiate the content and objectives of such measures (Palm & Reindl, 2016; Pihl, 2019; Reindl, 2020; Reindl & Palm, 2020). However, this study takes a novel approach by investigating the specific decision-making dynamics within renovation planning meetings, aiming to elucidate the circumstances under which energy efficiency initiatives face resistance compared to other agenda items. This focus on the nuances of professional practice provides new insights into the complexities surrounding the prioritisation of energy efficiency. Moreover, the comparative analysis of case studies from Sweden and Denmark offers a unique perspective on how cultural and institutional contexts influence energy efficiency practices. This cross-national examination enhances the understanding of varying approaches to energy efficiency, contributing to a more nuanced view of the challenges and opportunities in different settings. The methodological rigour of this study, utilising participatory observations, interviews, and document analysis, enables a comprehensive exploration of the negotiation processes that shape energy efficiency measures. This triangulation of methods not only strengthens the findings but also provides a distinctive dataset which highlights the intricate interplay between professional practices and energy decision-making.

Ultimately, the implications of this research extend beyond academic discourse; they offer valuable insights for policymakers and practitioners aiming to improve the implementation of energy efficiency measures in building renovations. By understanding the dynamics at play in decision-making contexts, stakeholders can develop more effective strategies to promote energy-efficient practices, thereby advancing sustainability in the built environment.

In the scientific literature, there is a wealth of studies advocating for the renovation of existing building stock to combat climate change, accompanied by numerous suggestions for areas of focus for both researchers and practitioners. For example, Zhao et al. (2019) conducted a bibliometric review of 2980 articles on green buildings, shedding light on the primary areas of research emphasis in this domain. Their study identified key research topics in green building, such as green roofs, vertical greening systems, water efficiency, energy performance, and life cycle assessment. They also highlighted knowledge gaps in areas like corporate social responsibility, real performance validation of green buildings, and the application of information and communication technologies (ICT) in green building design. Häkkinen and Belloni (2011) discussed the barriers and drivers for sustainable buildings, highlighting key actions to promote sustainability, including raising client awareness about the benefits of sustainable construction, developing, and implementing methods for managing sustainable building requirements, leveraging sustainable building tools, enhancing designers' competencies and collaborative efforts, and fostering the emergence of new concepts and services. Meanwhile, Janda et al. (2015) concentrated their research on enhancing energy efficiency in buildings, particularly focusing on energy reduction in residential homes. Their contribution lies in emphasizing the need for a broader understanding of energy demand through alternative epistemological approaches, such as constructivism and interpretivism, to explore more comprehensive and novel solutions beyond the dominant positivist approaches. Ayarkwa et al. (2022) underscored the significance of educating stakeholders on the future advantages of green buildings, involving personnel with a background in sustainable construction, and establishing sustainable priorities and objectives early in the planning stages of renovation projects to effectively address sustainability challenges in buildings.

Furthermore, numerous studies highlight the abundance of measures and technologies available to reduce energy consumption in residential buildings and the sluggish response of the building industry in embracing them. For instance, Economidou et al. (2020) offer an overview of energy efficiency policies for buildings in the EU, emphasising the positive impacts of these policies on enhancing the energy efficiency of building stock. However, they also address the challenges posed by the imperative to address climate change impacts in buildings, alongside opportunities for the building industry to leverage existing technologies. Similarly, Cabeza and Chàfer (2020) conducted an extensive review of academic literature concerning technological options and strategies for achieving zero-energy buildings. They note a deficiency in knowledge transfer regarding successful strategies implemented and a lack of cross-country information exchange concerning technologies for energy efficiency in buildings, a sentiment echoed by Lindkvist et al. (2014) in their examination of cases in Sweden and Norway. Moreover, Darko et al. (2017) delve into issues influencing the adoption of green building technologies from the perspective of experts. They highlight the resistance to change within the building industry, widespread ignorance among practitioners regarding green building technologies, and the substantial costs associated with these technologies as primary barriers hindering their adoption. Palm & Bryngelsson (2023) discuss similar barriers as Darko et al. but about the slow uptake of energy-efficient innovations at building sites. Regarding the abundance of existing measures and technologies, several authors also emphasise the mutually beneficial relationship between green architecture and energy efficiency. This could also be applied to advance energy efficiency in renovations even further (e.g. Chen et al., 2010; Umoh et al., 2024; Yuan et al., 2017). Green architecture refers to the integration of sustainable design principles, such as using renewable energy sources, energy-efficient systems, and eco-friendly materials, to minimize a building's environmental impact. Energy efficiency, in turn, focuses on optimizing the performance of energy systems, insulation, and HVAC systems within buildings to reduce energy consumption and environmental impact.

However, focusing solely on energy savings risks overlooking the broader environmental performance of buildings, particularly regarding embodied energy and material lifecycle impacts (Duan et al., 2024). This concern is increasingly acknowledged in policy frameworks such as the revised Energy Performance of Buildings Directive (EPBD) (European Union, 2024), which incorporates provisions for lifecycle greenhouse gas emissions. This includes embodied carbon from materials and processes associated with construction, renovation, and deconstruction. By integrating these considerations, renovations can align energy efficiency improvements with comprehensive sustainability goals, a critical step toward mitigating climate change.

Building owners and occupants pose additional challenges to adopting energy-efficient technologies in buildings. Schleich (2019) underscores the necessity for supportive schemes targeting medium and low-income households, as they often lack the means to implement even basic energy efficiency measures such as appliances and utilities. Giraudet (2020) delves into information asymmetries that contribute to the inadequate adoption or outright rejection of energy efficiency measures by building owners and tenants. Meanwhile, Melvin (2018) highlights the reluctance of building owners to invest in energy efficiency measures, resulting in higher energy bills for tenants and promoting poor energy behaviour within buildings. Vogel et al. (2016) identify several problem areas regarding energy efficiency implementation in Swedish multifamily buildings. These include poor communication of the benefits of energy efficiency measures from professionals to building owners, increased costs for occupants due to ambiguous energy-related rules and regulations (such as unclear guidelines for energy-efficient investments, fluctuating subsidies, and inconsistent building performance standards), unclear incentives for supporting building owners in adopting energy efficiency measures, and an overall lack of transparency regarding energy pricing models, information communication, and planning and delivery processes.

The existing literature offers a diverse array of studies examining building renovation from various perspectives, including those that highlight potential economic benefits from a technical standpoint, such as Abu-Hijleh et al. (2017), and Paganin et al. (2017). Additionally, studies are adopting a market-oriented approach, focusing on investment decisions and economic factors influencing renovations, exemplified by works such as Elliott et al. (2015), Alberini et al. (2014), and Rasmussen (2017). A third stream of research concentrates on the development of business models aimed at supporting energy renovations of existing building stock. This includes studies by Bianco et al. (2022), Brown (2018), Brown et al. (2022), D’Oca et al. (2019), Mihailova (2023), Mlecnik et al. (2019), Pardalis (2021), and Pardalis et al., (2020, 2022). These studies provide valuable insights into the financial and operational frameworks necessary to facilitate and incentivise building renovation initiatives, ultimately contributing to the sustainable transformation of the built environment.

Focusing solely on the physical, technical, and economic (PTE) aspects of renovations, as emphasised by Hampton (2019), overlooks the crucial dimension of social practices involved in delivering energy-efficient solutions in buildings. Each organisation interprets information, advice, and reports on energy efficiency through the lens of its traditions, cultures, and established practices, leading to unique processes of alignment (Hampton, 2019). While a significant number of studies on energy renovations adopt a scientific and technological perspective, relatively little attention has been paid to the social practices and assumptions that influence how and whether these technologies are practically implemented (Yarrow, 2016). Understanding the social dynamics and organisational behaviours surrounding energy renovation initiatives is essential for effective implementation and long-term sustainability.

Authors studying energy renovations predominantly concentrate on the impacts of policy instruments on various stakeholders. This includes examining the effects of policy measures on local governments, local manufacturers, and households, as demonstrated by studies such as Spyridaki et al. (2016), Fawcett et al. (2019), or Taranu and Verbeeck (2018).

Other topics encompass a historical perspective on how individual citizens engage with energy efficiency (Bănică et al., 2024), households' attitudes toward energy-efficient measures (Broers et al., 2021; Pelenur, 2018), and how residents in housing cooperatives make decisions regarding energy efficiency during renovation projects (Blomqvist et al., 2022; Hauge et al., 2013; Palm et al., 2020; Petrov & Ryan, 2021). Palm et al. (2020) study the experience and attitudes toward energy efficiency renovations of tenants living in public housing in Sweden, pointing also to a research gap in this area. There are diverse tenants' perspectives, and they see it as challenging to influence decisions regarding renovations. What would be needed is good communication and strategies to improve the understanding and acceptance of energy efficiency projects. Also, tenants have a lot of knowledge about the buildings, they live in and could be used more as a resource in a renovation project. Regarding companies, scholars delve into how standards impact the sustainable performance of companies (Brem et al., 2020), and the execution of energy management in small and medium-sized enterprises (SMEs), as explored by Hampton (2019). Despite the growing interest in studies focusing on social practices, there remains a notable gap in attention toward the design and planning practices of professionals in this domain as most attention is paid to individuals or households (Bartiaux et al., 2014). Building upon the comprehensive understanding of energy use in buildings and the diverse stakeholders involved, it becomes evident that decisions regarding energy efficiency are most effectively implemented when addressed early in the process. Aligning with the insights provided by Bavaresco et al. (2020) regarding the interconnected roles of stakeholders, prioritising energy efficiency considerations at the outset of building design and planning allows for seamless integration of optimal solutions and technologies. This proactive approach ensures that decisions made by occupants, designers, managers, operators, policymakers, technology developers, and vendors align with energy efficiency goals from the outset, maximizing the potential for sustainable and energy-efficient building outcomes. By recognising the importance of early decision-making in energy efficiency initiatives, stakeholders can streamline implementation efforts and mitigate the need for costly retrofits or modifications in the future.

More recent research on Positive Energy Districts (PEDs) has focused on the importance of energy-efficient renovations in their implementation as a key component in urban energy transitions toward climate neutrality (Bruck et al., 2022). PED projects are diverse in terms of their typology, land use, and design, with a strong emphasis on the integration of new developments with existing urban structures (Bossi et al., 2020). The recent literature on PEDs emphasises the importance of advanced tools and frameworks to support decision-making in renovation projects. Several studies highlight the critical role of multi-criteria decision analysis (MCDA) in evaluating the economic, social, and environmental impacts of PED renovations (Bisello et al., 2023, Aparisi-Cerdá et al., 2024). Digital twins have emerged as a powerful tool for simulating energy flows, optimising renovations, and integrating real-time data to manage the complexity of PEDs (Maiullari et al., 2024; Malakhatka et al., 2024). Additionally, cost–benefit analysis (CBA) combined with multi-criteria tools supports the evaluation of long-term sustainability and social benefits, as seen in the frameworks proposed by Bottero et al. (2021). These findings identify the need for integrated digital tools and economic frameworks to facilitate effective, sustainable PED renovation projects.

To summarise, there are several key ideas from earlier research to be considered in the analysis. Research highlights the importance of early planning and stakeholder involvement to align energy efficiency goals with renovation efforts. Renovation of existing building stock is widely seen as crucial to mitigating climate change, with various studies emphasising both technical and social dimensions. Technologies such as models and calculations are tools that can be used to optimise energy efficiency during renovations, but they also need to be translated to the specific context so they will be used and existing professional practices. Barriers and drivers to sustainable renovations, such as stakeholder competence and practices, collaborative design, and financial issues, are recurrent themes identified as important in earlier studies. However, before discussing the findings, the methodology will be described.

This study employs a methodological approach that focuses on the comparison of the results of two case studies—one from Sweden and one from Denmark—utilizing a mix of three qualitative research methods in triangulation: observations, interviews, and document studies. The triangulation enhances the depth and validity of the findings (Hennink et al., 2020; Creswell & Creswell, 2018). Originally, the research in Sweden and Denmark was conducted by different research teams. However, the research teams from Sweden and Denmark realised that the two cases share significant similarities regarding their context, challenges, and outcomes. Comparing and combining the two cases enhances and underlines the impact of the findings, adding value to the research on energy efficiency in building renovations.

The study employs qualitative methods to explore the nuances of decision-making processes surrounding energy efficiency measures. While interviews provide valuable insights into professionals' perspectives (Schwarz, 1999), they often cannot fully capture the complexities of prioritisation in planning and design. The methodology for both cases included a combination of qualitative research methods such as observations, semi-structured interviews, and document analysis. However, due to the differing scales and organizational structures of the Swedish and Danish cases, the number of meetings, interviews, and documents varied. Therefore, participatory observations are employed to immerse researchers in the natural settings where these practices occur (Angrosino & Rosenberg, 2011; Mohajan, 2018; Moser & Korstjens, 2018; Musante & DeWalt, 2010). This dual approach allows for a more comprehensive understanding of the context and dynamics influencing renovation decisions insights (Marshall & Bresnen, 2013; Reindl, 2020), fostering rapport with participants for richer insights (Musante & DeWalt, 2010).

The Swedish case involves three renovation projects from a municipal housing company, focusing on multi-family apartment buildings constructed between the 1950s and 1960s. A transdisciplinary approach was adopted, with collaboration among researchers from social sciences and engineering. In this case, researchers observed meetings without direct participation but engaged in collaborative discussions with the housing company to facilitate energy-efficient solutions (Ciesielska et al., 2018). In contrast, the Danish case centres on a single renovation project involving four apartment buildings from the 1960s. Here, researchers refrained from participating in discussions to minimise disruption, although some interaction was inevitable. Both cases included meetings with internal professionals from municipal housing companies and external consultants, although participation levels varied. In Sweden, internal and external professionals were actively engaged, while in Denmark, meetings primarily involved external consultants.

Semi-structured interviews with a total of 33 professionals from the Swedish case and 12 from the Danish case were conducted to explore their interpretations of the planning and design processes.. Table 2 offers an overview of the participants involved in the meeting for both cases.

Interviews with professionals engaged in the meetings aimed to uncover their understandings and interpretations of the design and planning processes. In Sweden, energy consultants were not interviewed separately, as energy considerations were integrated into the roles of other professionals, such as architects and project managers. Participants were selected for their important roles in the renovation projects, as their perspectives were crucial for understanding energy considerations during the planning and design process.

In both cases, the interviews explored how energy issues were incorporated into the planning and design processes. The Swedish case focused on interviewees' roles, perceptions of ongoing processes, project dynamics, the influence of professionals, energy efficiency considerations, tenant-related issues, and specific project observations. In the Danish case, interviews primarily addressed how designers negotiated and made decisions related to energy performance, as well as the processes and development from their perspective. The interview process in Denmark placed greater emphasis on energy consultants and experts, given their formalized role in the project.

Although the interviews were similar in both cases, the Swedish case had a broader focus, including the role of tenants, while the Danish case emphasized designers' negotiations on energy performance. In Denmark, the interview process began with preliminary interviews to understand the project's context and energy goals, followed by in-depth observations of design meetings. The researcher noted interactions and actions related to energy discussions, and follow-up interviews helped clarify these observations. All interviews were recorded, transcribed, and analyzed using qualitative data analysis software. Each session typically lasted between one and two hours.

To complement the data from interviews and observations, a document study was conducted for both cases (Bowen, 2009). The documents analyzed included descriptions, blueprints, sketches, photos, meeting protocols, and tender documents (post-planning and design phase). In Sweden, additional documents from a 2009 renovation project were reviewed to compare planning and design processes. Supplementary materials also included annual reports, process documents from the housing company, PowerPoint presentations, meeting minutes, and tender documents for each renovation project.

The document types varied between the Swedish and Danish cases due to differences in available documentation. Sweden provided a broader range of planning materials, while Denmark's documents focused more specifically on design and energy performance discussions. Although not all documents underwent in-depth analysis, they contributed to a deeper understanding of each renovation project. The triangulation of interviews, observations, and documents ensured the accuracy and consistency of the findings (Flick, 2018). A summary of the data collection sources for this study is presented in Table 3.

The section encompasses the results of the comparative analysis organised after the the five identified themes:

Both the Danish and Swedish cases were renovations with a specitic focus on energy. Despite the expressed ambitious goals by the building clients in both Denmark and Sweden to reduce energy consumption, discussions among the professionals during meetings did not prioritise energy performance. Instead, their time and attention were predominantly directed towards addressing other pressing issues, like budget constraints, compliance with regulations, scheduling and timelines etc.

In the Swedish case, discussions among professionals predominantly revolved around technical installations, particularly electrical and HVAC-related systems, with a notable emphasis on shafts and their impact on overall design considerations. Ventilation and heating systems, electrical outlets, and lighting were also common points of discussion. Additional topics included updates to elevators, ensuring accessibility in apartments, potential apartment layout changes, balcony modifications (such as enlargement or addition), modernization of laundry rooms, and measures to prevent pest ingress, notably rats. While fire safety was a recurring topic, it received less attention compared to electrical and HVAC installations, with consultants specializing in these areas playing dominant roles during meetings. Similarly, in the Danish case, professionals engaged in discussions covering a wide array of topics beyond energy issues. These included considerations such as the location and load-bearing capacity of concrete structures, routing of water and ventilation pipes, placement of shafts, materials and construction methods for building components, fire safety measures, facade design, elevator placement, floor finishing levels, acoustics, foundation requirements, and procurement documentation.

In both cases, standard meeting agendas served as the framework for interactions during the meetings. In the Swedish case, energy-related matters were not allocated a separate agenda point. If professionals wished to address any energy-related issues, they were typically relegated to the end of the meetings, leaving only a brief window of approximately five minutes for discussion. However, these discussions rarely delved into depth and were not revisited in subsequent meetings. In contrast, the meeting agenda in the Danish case included a specific item dedicated to energy-related issues. Nevertheless, compared to other agenda items, discussions on these matters were brief and received less attention from professionals.

In the Danish case, professionals regarded the renovation project as primarily an "architectural project," largely due to its inception through an architectural competition. Consequently, discussions predominantly revolved around reconciling new architectural expressions with the existing building's condition. Conversely, in the Swedish case, the primary objective for professionals was to enhance the living standards of tenants. As a result, their focus centred on technical installations, apartment layout alterations, and building constructions aimed at improving living conditions. Ultimately, in both cases, the professionals' primary goal was not centred on reducing energy consumption in the buildings. Energy-related concerns were comparatively less relevant and received less frequent discussion compared to other building-related matters.

Despite the ambitious energy goals set for the renovation projects in both cases, professionals did not dedicate significant time to energy-related discussions and predominantly relied on the so-called “standard energy efficiency measures” to reduce energy consumption.

In the Danish case, professionals perceived the renovation project as a "standard social housing project," indicating that building clients typically lacked the financial resources to explore innovative building techniques, materials, or technology. As a result, they opted for known, tested, and affordable solutions, aligning with the project's context as a social housing complex. Energy measures implemented in the Danish case included the installation of a new heating system, comprising new radiators, floor heating in select bathrooms, new boilers, and insulated pipes. Similarly, in the Swedish case, professionals adopted what they deemed as "standard measures" to enhance energy efficiency, such as replacing HRV ventilation systems, upgrading windows, and adding insulation. Energy-related discussions were brief, with professionals drawing largely on their routine and collective knowledge to select a "standard package of traditional measures." These measures were implemented with a pragmatic approach, guided by the principle of "let's do as much as we can and see what happens," and were based on a rule of thumb rather than extensive deliberation with energy calculation and measurements in the current buildings.

Based on observations from meetings, it was evident that professionals in both cases dedicated only a fraction of their time to energy-related discussions and problem-solving. In the Danish case, energy-related issues were discussed for approximately one hour out of a total of eleven hours across six observed meetings. The duration of these discussions varied from as short as two minutes to as long as twenty-five minutes. Interestingly, professionals in the Danish case engaged in more extensive discussions on energy-related issues compared to their counterparts in the Swedish case. Conversely, in the Swedish case, energy-related discussions were generally limited to five or ten minutes at the end of approximately two-hour meetings if they occurred at all. It is apparent from both cases that professionals did not prioritise energy performance discussions to the same extent as other building design issues. Consequently, they tended to rely on known and tested solutions, opting to allocate their time towards technical installations or architectural matters.

In the Danish case, the energy specialist notes that energy performance was not deemed a "key issue" within the building client organisation. Their primary focus lied in renovating apartments to a high standard, ensuring the comfort and well-being of tenants. While acknowledging the potential for greater ambition in addressing energy demands, the energy specialist, and a structural engineer both characterised the project more as an "architectural project" than an "energy project." Similarly, in the Swedish case, professionals expressed similar sentiments. An internal consultant observed that participants involved in the projects had developed routines over the years, suggesting that they may have followed established practices, both beneficial and detrimental. An external consultant echoed this observation, noting the repetitive nature of energy measures across projects, describing it as a standard process involving familiar steps. These statements exemplify how professionals perceived the projects as relying on "standard" solutions and adhering to "business as usual" practices, particularly concerning energy-related concerns.

The renovation projects examined in both cases implemented a range of energy measures that align with established practices within the building industry. These measures typically included replacing windows and doors with newer, energy-efficient models, installing updated ventilation systems with heat recovery capabilities, enhancing insulation for walls and roofs, and upgrading to more efficient electrical appliances. While these approaches are widely recognized and considered standard for improving energy efficiency, there was limited exploration of innovative ideas, developments, or experimental strategies that could further enhance energy performance. For instance, there were no considerations of incorporating smart home technologies that optimize energy use based on occupancy patterns, or use of advanced materials such as phase-change materials for better thermal regulation, or integrating renewable energy sources like solar panels and battery storage systems. By adopting these innovative practices, renovation projects could achieve significantly greater energy savings and contribute to overall sustainability.

Moreover, discussions on energy issues during meetings were not extensive, indicating that professionals did not prioritise in-depth deliberations on energy-related topics. Instead, the focus remained on implementing familiar and proven energy measures without exploring more advanced or groundbreaking solutions.

An energy calculation often carries an elusive quality, akin to a mythical creature like a unicorn, as described in one of the interviews. This analogy holds true in both case studies presented here. In the Danish case, professionals frequently mentioned energy calculations during meetings, yet these calculations were never visually presented, nor did any reports based on them surface during discussions. Similarly, in the Swedish case, calculations were typically carried out by external HVAC consultants, with many meeting participants unaware of their existence. In one instance, even the project leader was unaware of the calculations being conducted, referring to the individual responsible as a "shadowy figure." In both cases, energy calculations remained confined to professional practices outside of meeting settings, remaining hidden from many participants. This disconnect underscores the challenge of integrating energy-related considerations into project discussions effectively, highlighting a gap between theoretical knowledge and practical implementation within the context of building projects.

In both cases, the determination of energy requirements necessitated calculations. For the three buildings examined in Sweden, energy consumption figures were recorded at 153, 141, and 154 kWh/m^2/year. While meeting Swedish building standards served as an implicit goal, this objective was tacitly understood rather than explicitly discussed. Implicitly, the goal in the Swedish context aimed to achieve a building energy performance of 80 kWh/m^2/year. Similarly, in the Danish case, the building client established energy demand criteria based on requirements outlined in the Danish building code. Specifically, a portion of existing buildings must adhere to an energy demand standard of 30 kWh/m^2/year plus an additional 1000 kWh/year divided by the heated floor area, as stipulated in the Danish building code. Both sets of energy demands necessitate calculations, as they represent cumulative figures describing energy consumption derived from theories of thermal energy transport in physics applied to spatial units. Documenting compliance with these demands involves a process of translation, whereby the conceptual energy demands are converted into tangible numerical representations on paper.

In the Danish case, professionals frequently mentioned and alluded to energy calculations throughout the project, particularly in the initial stages. However, most professionals were not fully versed in the implications of the energy demands specified in kilowatt-hours about building design. Therefore, they awaited guidance from the internal energy consultant who conducted calculations and provided directives on how to meet the specified demands. Close to the design project's handover, an architect informed the team that the energy consultant had compiled a report based on calculations. However, the architect admitted to not having seen the report during the design process, a sentiment confirmed in a subsequent interview.

In the Swedish case, energy calculations were conducted by an external HVAC consultant. According to interviews with HVAC consultants, performing energy calculations was considered standard practice within the industry. However, despite the presence of these calculations, the project manager was unaware of their existence. This lack of awareness led the project manager to characterise the role of the HVAC consultant as a "shadowy figure," as it remained unclear who was responsible for conducting the calculations or even for whom they were conducted. Like the Danish case, professionals involved in the Swedish project did not engage in discussions regarding energy calculations during meetings, and the calculations themselves were not presented to the professionals. This highlights a common trend across both cases where energy calculations were conducted without direct involvement or visibility to key project stakeholders.

In both cases, specific individuals are tasked with ensuring that the projects adhere to the energy demands stipulated by the building clients. However, these individuals are frequently absent or passive during observed meetings, leading to confusion, protracted discussions, and the implementation of flawed energy-related solutions. The prevalence of this absence and passive attitude is largely attributable to the organisational structure of the projects.

In the Danish case, an internal energy consultant was tasked with ensuring compliance with requirements for energy performance and indoor environment standards in buildings. However, due to being assigned to multiple projects simultaneously, the energy consultant was not fully dedicated to the renovation project and was only involved on a partial basis. Consequently, the energy consultant was frequently absent from meetings, leaving questions regarding energy calculations and other related issues unanswered for extended periods during the design process. In the Swedish case, a new internal group, known as the energy group, had been established by the housing company to oversee the energy performance of buildings. However, given the recent establishment of this group, both its members and other professionals involved in the renovation projects were unclear about the specific roles and responsibilities within the group. Additionally, the introduction of a new energy goal further complicated matters, requiring the group to determine how to address energy-related concerns and translate these new objectives into their existing meeting practices. While some members of the energy group attended meetings, they often remained passive and did not actively contribute to discussions or raise energy-related issues.

In both cases, professionals exhibited a keen interest in understanding the implications of energy calculations for their building designs. Despite this interest, they were not provided with access to the calculations or reports summarising their outcomes. Moreover, the professionals responsible for ensuring compliance with energy demands—the energy consultant and the energy group—were either absent or passive during meetings, resulting in unanswered questions and delays in the design process. Consequently, the calculations remained concealed within the practices of the energy consultant and the energy group, detached from the meeting dynamics. This lack of engagement with the calculations poses challenges for meeting participants and hinders the progression of the design process.

The organisational structure surrounding financial decisions in the two cases exhibited both differences and similarities. Financial decisions played a crucial role in determining the extent to which energy efficiency measures could be implemented in both contexts. In the Danish case, the building client organisation opted to secure a loan to finance energy efficiency measures, albeit at the cost of increased rents for tenants. Conversely, in the Swedish case, an investment group oversees all financial decisions related to the renovation projects, including the implementation of energy efficiency measures and their profitability. Despite being a public housing company, the need to generate profit ultimately influenced decision-making. Rent increases also contributed partially to financing the renovation efforts. Overall, while the mechanisms for financing energy efficiency measures differed between the two cases, both highlighted the significance of financial considerations in shaping the implementation of such measures.

In Denmark, the renovation of social housing estates received subsidies from the National Building Foundation (NBF). This funding facilitated large-scale renovations of existing social housing complexes. During the study period, the NBF did not allocate additional funds for implementing extra energy efficiency measures beyond updating the buildings to meet current building regulations. Consequently, the aspiration to exceed these regulations required the housing and administration organisations to finance certain aspects of the renovation project themselves. The NBF contributed funding equivalent to 67 percent of the contract sum towards the renovation project. The remaining portion of the project costs was financed through a loan (29 percent) and internal financial resources within the housing organisations (4 percent). The project managers categorised all expenses in the renovation project into two distinct categories: subsidised work and non-subsidised work. Subsidised work primarily involved rectifying existing faulty constructions, while non-subsidised work focused on modernizing and maintaining the buildings for future use. Some expenses were allocated exclusively to one of these categories, while others were evenly divided between them. A significant factor contributing to the perception within the design team that the renovation project was merely a "standard renovation" was the financial model employed. With 67 percent of the funding earmarked for repairing and restoring the buildings, the project manager prioritised functionality over design considerations. In essence, the project lacked the financial resources for additional energy efficiency measures, unless the project participants opted to increase tenants' rent—a course of action the housing association sought to avoid.

In the Swedish case, a centralised investment group assumed responsibility for all financial decisions pertaining to the three renovation projects. Guided by a principle mandating that energy efficiency measures must exhibit a payback period of less than six years, proposals exceeding this threshold were more likely to face rejection. Members of the investment group viewed themselves as pessimistic regarding the demand for such a relatively short payback period. Consequently, economic considerations heavily influenced decision-making, prompting the planning and design team to predominantly opt for "standard" energy efficiency measures that required no additional investment decisions. However, even some of these standard measures were vetoed by the investment group. In one instance within the Swedish case, the existing distribution system, approximately 50 years old, required replacement. Despite this pressing need, the investment group initially resisted the idea due to associated expenses. Disagreement emerged within the planning and design team regarding this decision, with a project manager and an external HVAC consultant advocating for reconsideration. Eventually, the investment group relented and agreed to replace the distribution system following persuasive arguments of a technical nature. However, while the planning and design team successfully influenced this decision, their arguments were primarily based on technical considerations, with potential energy efficiency benefits of the new distribution system not thoroughly considered. The organisational structure surrounding decision-making, coupled with the rule imposing a six-year payback period, poses challenges to the energy-efficient design of renovation projects. Although the planning and design team succeeded in advocating for the replacement of the distribution system, their arguments predominantly focused on technical aspects, overlooking potential energy efficiency opportunities.

In both cases, energy goals were established as general frameworks for the buildings, delineated by energy consumption per square meter (kWh/m^2). However, these frameworks presented challenges to the professionals involved in the projects. In the Swedish case, professionals faced difficulties as they were often unaware of the specific energy goals determined by the building client. Conversely, in the Danish case, professionals grappled with the challenge of not knowing how to effectively design the buildings in alignment with the prescribed energy goals. The lack of clarity surrounding the energy goals and their implementation manifested differently in each case, highlighting distinct hurdles encountered by the professionals.

In the Swedish case, external consultants were unaware of the energy goal set by the housing company, which aimed to reduce purchased energy per square meter by 25 percent from 2011 to 2025, referred to as the "25–25 energy goal." While internal project members were informed about this goal, it was not explicitly communicated to external consultants during the planning and design phase. The housing company expected these professionals to consider the goal, assuming they were aware of previous projects, leading to a lack of awareness among most external consultants. Conversely, in the Danish case, professionals were aware of the energy goal, which aimed for the buildings to meet energy frameworks corresponding to 20–30 kWh/m2/year, as estimated by the administration organisation. However, despite this seemingly specific energy goal, professionals were unsure how to design the buildings to meet such a generalised description of energy consumption. This uncertainty led to numerous questions from professionals in initial meetings, highlighting a lack of clarity and guidance regarding the implementation of the energy goal.

In the Swedish case, professionals reiterated during meetings the objective of reducing energy consumption "as much as possible." However, discussions rarely delved into specific strategies or approaches to achieve this reduction. Additionally, the housing company evaluated the "25–25 energy goal" based on statistics encompassing their entire portfolio of housing estates, rather than focusing on individual renovation projects. This approach resulted in a disconnect between the broad formulation of the goal and the practical implementation by professionals. Moreover, professionals failed to translate the overarching goal into tangible guidelines or frameworks tailored to the specific buildings undergoing renovation. As a result, there was a notable gap between the general energy reduction goal and the actionable strategies adopted at the project level.

While the energy group in the Swedish case maintained a relatively passive role during the renovation projects, the energy consultant in the Danish case played a proactive role in translating the general framework into more specific requirements. For instance, the energy consultant authored a document delineating the U-values of main construction types, prescribed levels of airtightness, and the desired percentage of heat recovery for ventilation systems. This detailed documentation provided invaluable support to professionals by translating overarching frameworks into precise requirements for specific constructions and installations. Furthermore, as the project progressed, the energy consultant continued to assist professionals by furnishing information on insulation thicknesses and lambda-values for insulation at specific locations within the buildings to mitigate thermal bridging. In this capacity, the energy consultant adeptly translated general U-values into even more specific data, such as lambda-values, facilitating informed decision-making and ensuring compliance with energy efficiency standards.

The lack of awareness among professionals regarding energy goals, coupled with the absence of discussions on energy issues during project meetings, posed significant challenges when the primary aim of building renovations was to reduce energy consumption. Furthermore, the inability of professionals to effectively address energy goals formulated in general terms exacerbated this challenge. To adequately support professionals in designing energy-efficient buildings, it was imperative to translate general goals into specific requirements and foster discussions around these requirements. This process enabled professionals to better comprehend and implement energy efficiency measures tailored to the unique needs of each project. By facilitating a clear understanding of specific energy targets and associated strategies, professionals could more effectively contribute to the overarching goal of reducing energy consumption in building renovations.

The comparative analysis of Swedish and Danish renovation projects revealed several critical insights into how energy efficiency goals are addressed—or overlooked—during planning and implementation phases. Duarte & Picchi (2021) identified several factors which can contribute to enabling systemic innovation in the construction industry such as an innovation strategy, external collaboration, having a champion and customer-centricity. Organisational and processual aspects are also crucial, including upper management support, an innovation culture, and an incentive system supporting innovation. The financial aspects, particularly a budget for energy-related innovation, are essential for fostering energy-efficient choices in the construction industry. Most of these aspects were present in our case studies, but a more systematic work with these was lacking. Energy became an add on, which was discussed, but not systematically followed up with for example support from a multi-criteria tool (Bottero et al., 2021). The use of such a tool would have provided a structured framework for evaluating the energy impacts of various design options, ensuring that energy efficiency was consistently considered alongside other important factors like budget and functionality. This could have facilitated more objective decision-making and led to more effective integration of energy goals into the projects. The lack of established energy practices, routines and a systematic work with energy in the planning and design phase is the main reason to why the energy goals where not fully implemented. This together with failures in relation to different elements in the process led to the final outcomes in the projects.

The cases demonstrated a common pattern: while energy efficiency is an overarching objective, professionals’ focus often shifts towards more immediate technical or architectural issues, reflecting the practical pressures of budget constraints, compliance, and other building design aspects, confirming findings in previous research (Cabeza and Chàfer, 2020; Hampton, 2019; Chen et al., 2020). In both countries, energy-related discussions, while present, were brief and ended up secondary to other considerations such as HVAC systems, electrical installations, and tenant comfort improvements. This prioritization gap suggests a misalignment between stated energy ambitions and the everyday realities faced by professionals in renovation projects. It also reflects a broader issue within the industry where energy efficiency is not always accorded the emphasis it deserves, despite its crucial role in ensuring long-term sustainability. A way to work with this is to introdrocue clear standards- procedures an routines which would contribute to make energy a mandatory issue similar to many other issues in the planning and design phase.

Umoh et al. (2024) discuss the mutually reinforcing relationship between green architecture and energy efficiency, which has the potential to advance energy efficiency in renovations even further. This integration of green architecture and energy-efficient practices is crucial in contemporary construction, as it combines various strategies like passive design, green roofs, efficient insulation systems, and renewable energy solutions. These strategies not only reduce energy consumption but also contribute to a healthier indoor environment and a more sustainable building life cycle. This mutually reinforcing relationship did not appear in the Danish and Swedish cases. The findings of this study rather reveal the opposite of this innovative green design where there existed a prevalent reliance on conventional measures and traditional renovation methods, which also have been observed in earlier reserach (e.g. Ajayi et al., 2016; Hemström et al., 2017; Palm & Reindl, 2018; Reindl, 2017). Instead of exploring new and innovative approaches to energy efficiency, the professionals often stuck to what they knew (Hampton, 2019; Mlecnik et al., 2019; Pardalis et al., 2020; Palm & Bryngelsson, 2023) and relied on familiar, standard energy-saving methods, which included updating windows, ventilation, and insulation. These measures, although effective to a degree, reflect a reluctance or inability to adopt more progressive or experimental technologies that could enhance energy performance further. One key reason for this is the financial constraints surrounding these projects, especially in the Danish case, where budget limitations linked to social housing finance models were evident. In Sweden, financial decisions were heavily influenced by strict payback periods, leading to the rejection of potentially impactful but costly energy measures. That limited financial resources and budget constraints often hinder the adoption of more ambitious energy efficiency initiatives have been shown in earlier research (Giraudet, 2020; Reindl, 2017; Reindl & Palm, 2020). Different solutions have been discussed in earlier studies such as public–private partnerships and incentive programs (Schleich, 2019; Pardalis et al., 2020, 2022). Such potential alternative financing options was however not at all up for discussion in our cases. Since the financial aspect is such a basic principle for success in energy renovation, this seems like an obvious issue to bring into future renovation processes.

Digital tools and economic models were present in the processes (Bottero et al., 2021; Bisello et al., 2023; Aparisi-Cerdá et al., 2024). A notable challenge identified in both cases was however the difficulty professionals face in understanding and using energy calculations and the models effectively. This points to a broader issue within the organisational structures, where energy expertise is not fully integrated into the core planning process. In both Sweden and Denmark, energy calculations were often conducted by specialists who were either absent or passive during project discussions, leaving other team members with little practical guidance on how these calculations informed building designs (Ayarkwa et al., 2022; Darko et al., 2017). The energy consultant in the Danish case could however serve a good example. The consultant played a key role in translating general energy efficiency frameworks into specific, actionable requirements. He authored detailed documents which offering crucial guidance to the other professionals in the process. As the project advanced, the consultant continued to provide precise data on for example insulation thickness enabling informed decisions on construction and installation practices. This is a good practice worth exploring and integrating more in future renovation processes. Both cases highlight how the overarching energy objectives are often lost in translation during the design process. In Sweden, external consultants were frequently unaware of the energy goals set by the client, while in Denmark, professionals struggled with the lack of clarity on how to design for specific energy targets. This emphasises the need for clear, detailed documentation and proactive engagement from energy consultants ensuring that the discussions about energy consumption have the specificity needed for impactful decision-making. A general problem was that the energy objectives lacked the specificity and granularity necessary to guide effective decision-making at the project level which contributed to the gap between the goals and implemented measures.

Further studies are required to explore shifts in organisational practices prioritising energy goals within different housing companies conducting renovations. Investigating successful case studies of organisations embracing an energy-conscious culture can unveil the drivers, hurdles, and strategies employed in fostering commitment to energy efficiency. The case studies are focused on Sweden and Denmark, future research could also focus on other geographical regions but still have a triangulation approach. With results from other countries, it would be possible to compare the findings from Sweden and Denmark. A notable constraint lies in the short-term focus of the observations; however, there is ample room for future investigations to broaden the scope by delving into additional projects.

This study's comparative analysis of Swedish and Danish renovation projects underscores the gap between energy efficiency ambitions and their implementation in practice. While energy efficiency was recognized as a goal, it was frequently treated as an secondary issue rather than a primary focus. Building on previous studies that highlight the crucial role of building professionals in either facilitating or hindering energy efficiency initiatives, the interaction between competing priorities and the challenges faced by energy efficiency measures was examined.

Despite ambitious energy goals set by building companies, barriers and gaps continue to hinder hinder effective implementation. The findings demonstrate that the absence of established energy routines and systematic processes during the planning and design phases is a significant barrier to achieving energy goals. Both countries exhibited a reliance on conventional renovation methods, primarily due to financial limitations and structural barriers within the organisations involved.

Financial constraints pose a significant barrier to the adoption of more ambitious energy efficiency measures. Limited financial resources and budget constraints often restrict the feasibility of implementing innovative energy-efficient solutions, highlighting the need for alternative financing mechanisms and incentive programs. Without sufficient financial support, projects are likely to continue relying on standard solutions, which, while beneficial, do not maximise the potential for energy savings.

Other barriers related to energy calculations and the delineation of responsibilities further complicate the planning and design process. The lack of visibility and transparency surrounding energy calculations, coupled with uncertainties regarding roles and responsibilities, led to inefficiencies and misunderstandings. In both cases, energy consultants (internally and externally) were not fully engaged with the broader project teams, leading to a disconnect between the theoretical energy targets and practical design solutions. The role of energy consultants, particularly in the Danish case, exemplifies however a promising practice for bridging the gap between general energy targets and specific, actionable requirements. The study points to the need for more widespread and systematic engagement of energy consultants in renovation processes and more detailed, specific guidance to translate broad energy goals into actionable strategies. Thus, consultants can play an important role in renovation projects by bridging the gap between energy efficiency goals and practical project implementation. They can act as intermediaries influencing critical decisions regarding the implementation of energy measures as they can translate broad energy targets into specific and more actionable strategies which is essential to advancing sustainable renovation practices. This is especially important in the early planning phases.

However, as the article indicates, energy consultants often face limitations, especially in Sweden. It is suggested that integrating energy consultants and their expertise more systematically into decision-making processes can enhance project outcomes, ensuring energy objectives are met without compromising other design priorities.

To address these challenges identified in the studied cases, future renovation projects should incorporate clear standards, procedures, and routines to ensure energy efficiency becomes a mandatory focus in the planning and design phases.