Improving building envelope components, such as windows, is a common renovation measure in cold climates to increase energy-efficiency. However, the life cycle (LC) benefit of maintaining or replacing windows is highly uncertain and depends on the building, its context and methodological choices made in LC assessments. This study aimed to expand knowledge on how buildings' characteristics and local context (location-related) influence the preferred window intervention option by investigating the LC climate impact and costs of various window maintenance and replacement scenarios for two typical residential buildings in subarctic Sweden. Using life cycle assessment and life cycle costing, along with sensitivity analyses of seven relevant parameters, the study explored the total climate impact and costs over a 60-year period for each window intervention's production and operational stages. Results indicate that building characteristics are important, as the two buildings show contrary LC results, even within the same local context. Swapping the buildings' location affects initial LC performance, and which sensitivity parameters appear critical. The parameters influence the LC results, but only a few alter the window interventions' rankings, with heating emission factor having most impact. Reducing LC climate impact and costs by replacing windows is not guaranteed, as it depends on building characteristics and local context. Instead, window maintenance may be preferred for its lower material use. The study's integrated LC approach provides insights for harmonizing renovation budgets with climate targets. Adapting renovation measures to each specific case is key for choosing the best option, balancing operational and embodied impacts.

Purpose: Energy-efficiency measures have always been important when renovating aging building stock. For property owners, window intervention is a recurring issue. Replacement is common to reduce operational heating energy (OHE) use, something many previous building renovation studies have considered. Maintaining rather than replacing windows has received less attention, especially for multi-residential buildings in a subarctic climate where there is great potential for OHE savings. The objective was to assess the life cycle (LC) climate impact and costs of three window maintenance and replacement options for a 1980s multi-residential building in subarctic Sweden.

Design/methodology/approach: The options’ embodied and operational impacts from material production, transportation and space heating were assessed using a life cycle assessment (LCA) focusing on global warming potential (LCA-GWP) and life cycle costing (LCC) with a 60-year reference study period. A sensitivity analysis was used to explore the impact of uncertain parameters on LCA-GWP and LCC outcomes.

Findings: Maintaining instead of replacing windows minimized LC climate impact and costs, except under a few specific conditions. The reduced OHE use from window replacement had a larger compensating effect on embodied global warming potential (E-GWP) than investment costs, i.e. replacement was primarily motivated from a LC climate perspective. The LCA-GWP results were more sensitive to changes in some uncertain parameters, while the LCC results were more robust.

Originality/value: The findings highlight the benefits of maintenance over replacement to reduce costs and decarbonize window interventions, challenging property owners’ preference to replace windows and emphasizing the significance of including maintenance activities in future renovation research.

The Swedish government has introduced a requirement to conduct a climate declaration for new buildings, and climate impact limit levels are set to be implemented by 2025. This has put pressure on structural engineers, who are an important part of the decisionmaking process regarding materials for and design of the superstructure of buildings. Since climate calculations usually occur towards the end of the project and are a timeconsuming and manual effort, structural engineers seldom evaluate the climate impact of their designs daily. The literature also suggests that while integrations of building information modelling software for structural engineering with climate calculation software exist, there is still a long way to go before this becomes fully automated. Moreover, even if automated, does this really help the housing companies and consultants where they are today? The aim is, therefore, to discuss the role of digital workflows in lowering the climate impact of residential buildings. This paper presents a case study examining a recently built apartment building in Northern Sweden in collaboration with the structural engineers and the housing company. The digital workflow used during the design phase was mapped, and several redesign ideas (e.g., climate-improved concrete, timber instead of concrete, innovative foundation design) were evaluated for their climate impact, cost, and feasibility from the perspectives of the architect, the client, and the contractor. The connection between theredesign ideas and the digital workflow is discussed. The results show that while there is potential for enhancing the building information models and tools used in the project, the digital workflow is not the primary challenge to reducing the climate impact. Instead, other factors, such as limited access to climate-improved concrete and a lack of early discussion of the climate impact of the design ideas between the different actors involved, present more significant challenges.

Previous building renovation studies have evaluated the life cycle (LC) impact of replacement to new, more energy-efficient windows, comparing it to optional renovation measures and base scenarios. However, periodic maintenance to avoid replacing existing windows has attracted less attention in research and practice, especially in subarctic climates with high heating demands by buildings. The objective here is to assess the LC impact of various scenarios of maintenance and replacement of different window types on a 1980s multi-residential building in subarctic Sweden. The scenarios were compared based on estimated climate impact and costs during product and operational stages. A reference study period (RSP) of 60 years was chosen. Results show periodic maintenance of existing windows to be the preferable option regarding LC climate impact and costs. In the replacement scenarios, the reduced heating energy use affected the climate impact more than the costs. The scenarios showed varied sensitivity to changes in RSP, intervention rate and discount rate, increasing the uncertainty of the assessment. The results highlight maintenance is worth considering among property owners when deciding on renovation measures, but also in future research studies. 

Research has shown that glazed buildings can have higher energy use and are more prone to overheating than other types of buildings. However, few studies have explored the performance of glazed buildings in cold climates. This article aims to evaluate the energy and indoor thermal performance of a high-rise residential building with glazed façades and balconies under Nordic climatic conditions, through a parametric study. Dynamic, whole-year simulations are used to evaluate the impact of four design parameters (with and without glazed balconies, type of balcony glazing, window to wall ratio, and building location within the Nordic region) on the energy and indoor thermal performance of the building. The results show that the building without glazed balconies outperformed that with glazed balconies. Changing from single- to double-pane glazing also helped to reduce energy use and overheating, as did lowering the window-to-wall ratio. Overheating of apartments was found to occur during the summer in five of the six locations simulated, which suggests that solar control strategies might be needed for glazed buildings even in a Nordic climate. This study highlights the importance of further research on glazed residential buildings, which are becoming more common in contexts subject to such climates.

Benefits of BIM are not being achieved as expected in the mainstream architecture, engineering, construction, and operation (AECO) industries. Here, we aim to contrast expected and realized BIM benefits in AECO companies and discuss explanations for why benefits proposed in literature have, or have not, been realized. A qualitative research approach is applied to collect and analyse interview data from 47 companies in Finland, Norway and Sweden. Findings show that realized benefits typically occur “within the current practice” of individual organizations' project-related work. In contrast, expected but not realized benefits are long-term, lifecycle oriented and challenge current business and practice. Our proposed explanations acknowledge that fully realizing the expected benefits of BIM suggested in the technology-driven research is restrained by the current sector state-of-practice and assumes a high degree of BIM maturity among all cooperating companies. Thus, we discuss how explanations relate to the fundamental change required to radically leverage the benefits of BIM, challenging both current ways of work and the ubiquitous assumption of clients as drivers for BIM implementation in the sector. Based on our research, we argue that client demand is insufficient to realize the promise of BIM. Suggested research implications include a need for greater supply-driven logic among suppliers of BIM expert services, and the integration of multi-disciplinary competencies within and beyond the traditional disciplines. The research demonstrates the gap between state-of-the-art BIM predicted in literature and mainstream industry's adoption and highlights the importance of extending BIM research to better account for socio-organizational and process aspects of benefits and adoption.

Green roofs are complex systems, with a vegetation layer covering the outermost surface of the building shell. An effective design may confer environmental and energy benefits. Most field studies evaluating green roof performance have been conducted in warmer climates with few studies of full-scale green roofs in cold regions. No study has so far evaluated the energy performance of a green roof in a sub-arctic climate. This study demonstrates the heat flow and thermal effect of an extensive green roof versus a black bare roof area on a highly insulated building in the sub-arctic town of Kiruna, Sweden, for the period from November 2016 to February 2018. Measured temperature and heat flux values were consistently higher and more variable for the black roof than the green roof, except during the snow-covered winter months when the responses were similar. The cumulative heat flux showed that the net heat loss was greater through the black than the green roof, but the values remained low. Overall, the study confirms that the energy benefit of a green roof on a highly insulated building in a subarctic climate is low.

Several of Sweden's Local Planning Authorities (LPAs) use developer dialogue processes between them and building actors to aid in the implementation of urban development projects. The idea is often to achieve ambitious local sustainability and to encourage a generally appreciated collaborative culture; however, processes of planners/developers interactions are challenging to manage in practice. In this study, we aim to depict and analyse a developer dialogue process used by a Swedish LPA in an on-going sustainable urban development project through the theoretical lens of organizational coordination mechanisms. Particular focus is placed on exploring how planners and develops interact while negotiating and implementing locally defined sustainability priorities. Empirical material was collected through document analysis, workshops and interviews with LPA representatives. Findings from the ongoing study indicates that the LPA manage a mixture of formal and informal interdependencies throughout in an attempt to achieve a greater fulfilment of their sustainability goals, and better outcomes in terms of product compliance. Furthermore, the use of coordination mechanisms for analysing the project seems to represent an important instrumental knowledge gap for better understanding sustainable urban development projects' implementation and outcomes.