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.

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.

Building retrofit is considered as a vital step to achieve energy and climate goals in both Europe and Sweden. Nevertheless, retrofitting solutions based merely on reducing operational energy use can increase embodied energy use, mainly due to altering the existing trade-off between the two. Considering this trade-off is vitally important, especially for retrofitting buildings located in cold climate regions, as reduction of operational energy use to meet standards of energy-efficient buildings may require a deep retrofitting that can considerably increase the embodied energy and thus be unfavorable from a Life Cycle Energy (LCE) perspective. This article presents a case study in which multi-objective optimization was used to explore the impact of a wide range of retrofitting measures on the aforementioned trade-off for a building in Sweden located in a subarctic climatic zone. The studied building was a typical 1980s multi-family residence. The goal was to explore and compare the optimal retrofitting solution(s) for the building, aiming to achieve Swedish energy-efficient building standards (i.e. new-build and near-zero energy standards). The results of the optimization indicated that (1) use of additional insulation in walls and roof, (2) replacement of existing windows with more energy-efficient ones, and (3) change of traditional mechanical extract ventilation to heat recovery ventilation are the primary and optimal retrofitting measures to fulfill the new-build Swedish energy standard and achieve highest LCE savings. However, to fulfill more far-reaching operational energy savings, application of additional retrofitting measures was required, increasing the embodied energy use considerably and resulting in lower LCE savings compared to the optimal retrofitting solution that only reached the Swedish new-build energy standard. The LCE difference between the optimal retrofitting solutions that fulfilled the new-build standard and the strictest near-zero (passive house) standard was 1862 GJ, which is equivalent to almost four years of operational energy use for the original building. This indicates that there is a limit to the reduction of operational energy use when retrofitting existing buildings, beyond which additional reductions can considerably increase the embodied energy and thus be unfavorable in terms of LCE use.

The energy performance of heritage buildings is attracting growing interest in research and practice. Accordingly, as shown by our literature review, increasing numbers of articles on energy-efficiency measures for heritage buildings are being published in peer-reviewed journals. However, there is no overview of how energy efficiency and heritage conservation have been approached in the studies. To address this gap we categorized and assessed the identified studies in terms of two key elements of such investigations: energy analysis and analysis of cultural heritage values. Most of the studies evaluate and propose measures to reduce the operational energy use of single heritage buildings, and fewer have applied a broader system perspective. Moreover, the underlying notion of the buildings’ cultural heritage values seems to have been derived mainly from international conventions and agreements, while potentially significant architectural, cultural and historical factors have been rarely discussed. Our findings highlight that, when considering energy improvements, cultural heritage values should be more explicitly articulated and analysed in relation to established conservation principles or methodologies. Besides further scientific study, this point to the need of designing best-practice approaches that allow transparency and knowledge sharing about the complex relationships between energy efficiency and heritage conservation of buildings.