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.

Adopting energy efficiency strategies in residential buildings are beneficial as these not only improve the energy performance but also improves the indoor thermal climate and minimizes the greenhouse gas emissions. There exist numerous studies on energy efficiency strategies and their influence on indoor thermal climate in residential buildings in cold climates. However, there is a lack of documented and systematic studies that explicitly investigated the selection of appropriate energy efficiency strategies and their impact on the indoor thermal climate in residential buildings in a subarctic climate. Moreover, the impact of such energy efficiency strategies on the life cycle energy use of buildings has not been given appropriate attention in the existing literature. Due to the extreme climate conditions in a subarctic climate – severe cold and dark winter with heavy snow and mild short summer – buildings require a considerable amount of heating energy to maintain a comfortable temperature indoors. Therefore, it is important to adopt energy efficiency strategies that can help obtain operational and life cycle energy savings along with a better indoor thermal climate.

The aim of this study is to evaluate the impact of different energy efficiency strategies on energy use and thermal indoor climate of three selected case study residential buildings in a subarctic climate. Three research questions were formulated: (1) What is the impact of evaluated energy‐efficiency strategies on the operational energy use?, (2) What is the impact of evaluated energy‐efficiency strategies on the life‐cycle energy use?, and (3) What is the impact of evaluated energy‐efficiency strategies on the thermal indoor climate? To address research questions 1 and 3, implemented energy‐efficiency strategies in two low‐energy buildings were evaluated using measured energy data and dynamic building energy and indoor climate simulations. To address research question 2, different combinations of energy efficiency strategies were explored using a multiobjective optimization method to identify optimal retrofitting solutions in terms of life cycle energy savings for a 1980s building.

Results show that besides an airtight and highly insulated building envelope, a well‐functioning heating system is important to achieve low operational energy use. Findings highlight that the role of occupants is vital both in regard to the proper functioning of the heating system and to reduce the need for active heating in an airtight and highly insulated building. The occupants are also important in terms of maintaining a comfortable indoor thermal climate, especially during summer since manual airing and shading can help moderate temperatures indoors. Furthermore, findings show that applying glazed balconies is not necessarily a favorable strategy in terms of operational energy use and indoor thermal climate for a building in a subarctic climate. In comparison, using double instead of single pane balcony glazing and lowering the window to wall ratio improved the operational energy and indoor thermal climate performance. A combination of energy efficiency strategies including the addition of insulation on walls and roofs, there placement of windows from double pane to triple pane ones and the installation of heat recovery ventilation were found optimal to achieve considerable savings in both operational and life cycle energy use. In many cases, the fundamental aim of adopting energy efficiency strategies is to reduce operational energy use, while impacts on life cycle energy use and indoor thermal climate are less prioritized. The findings illustrate the importance of considering impacts on operational energy use, life cycle energy use and indoor thermal climate simultaneously to select energy efficiency strategies that ensure a better and more sustainable built environment.

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.

As the operational energy use in buildings contributes highly to the total energy used and greenhouse gases emitted in the cold climate regions of Europe, buildings which are more energy-efficient and less carbon-intensive during operation are key to meet sustainability objectives in these regions. Yet, research shows that the practice of passive or low-energy buildings in the sub-arctic climate of northern Sweden is comparatively less than in the southern region. Moreover, previous studies did not explicitly examine the performance of low energy buildings in sub-arctic climate in relation to established building energy efficiency standards. Consequently, knowledge regarding the energy performance of low-energy buildings in such climate is limited. Therefore, the aim is to evaluate the performance, in terms of indoor temperature and energy use for heating, domestic hot water and electricity of a new-built passive house titled “Sjunde Huset” in the sub-arctic town of Kiruna. It is Sweden’s northernmost house designed to fulfil the Swedish passive-house criteria of a maximum heat loss factor of 17 W/m2 and a maximum annual energy use of 63 kWh/m2. The implemented passive design strategies include a highly insulated, compact and airtight building envelope with a vestibule, mechanical ventilation with heat recovery and renewable energy production through photovoltaic solar cells. The house is connected to district heating and is equipped with energy-efficient appliances to allow low occupant energy use. Ongoing performance evaluation is based on building simulation and measurements of energy and temperature in different zones of the building. Energy performance deviations between occupied and non-occupied zones are explored through internal heat gain evaluations. The indoor temperature is also evaluated to assess the temperature variations throughout the year. The ongoing research further evaluate a comparative simulated and measured energy analysis of heating, hot water and electricity based on both the international passive house standard and the Swedish passive house criteria “Feby 12”.

The town of Kiruna, founded in 1900 in the northernmost part of Sweden, is nowadays in the middle of an impressive urban transformation: due to the impacts of mining activities a large part of the city center has to be moved or rebuilt. Among the buildings to be moved and kept in use are some of the so-called ‘Bläckhorn’ timber houses, designed by Gustaf Wickman in the early 20th century as residential units for the workers of the mining company LKAB and part of the original core of Kiruna. This has raised several questions on the sustainability of renovating historic buildings in a sub-arctic climate. In order to explore the challenge of increasing the energy efficiency of the Bläckhorn houses, data on their constructional and historical features as well as their thermal and energy performance have been collected. The paper addresses the following issues. Historic buildings are often blamed for their poor energy efficiency without considering their usually high constructional quality. What do we know about the real performances of these buildings? Energy retrofits in non-monumental and inhabited historic buildings are often guided by practical and operational needs rather than by their heritage significance. Can a value-based approach affect the improvement of energy efficiency? In a subarctic climate, even simple interventions can help to save a considerable amount of energy in historic buildings. To which extent the energy performances of the Bläckhorn houses could be increased without affecting their heritage values?

The paper presents results from the research project “Smart energieffektivisering av kulturhistoriska byggnader i kallt klimat”. The research is expected to develop, test and assess methods and solutions to increase the energy efficiency of heritage timber buildings in the northernmost part of Sweden.

The sub-arctic climate, with long, cold winters and mild summers, requires a significant use of energy, especially in historic buildings. This means that the difference in thermal performance and energy use with newly built buildings is greater and, at the same time, that even non-invasive interventions can be enough to save a considerable amount of energy with a limited impact on heritage values.

Valuable timber buildings from the late 19^th and early 20^th century are analysed in the cities of Piteå, Malmberget and Kiruna. Results are based on data collected on their energy and thermal performances, on the analysis of their constructional features and on the assessment of their heritage value.

People living in the coastal regions of Bangladesh suffer extremely due to floods. Every year 20% of the land mass (∼27,000 km2) and 30 million inhabitants are exposed to flooding that triggers casualties, infrastructural damage, and deprived access to basic needs. Many policies and strategies already exist for managing flood-related disasters. Flood-shelters save lives but rarely equipped with sufficient food, clean water, sanitation, and electricity. New strategies are required to provide resilience in flood prone areas. This conceptual paper presents an innovative and integrated approach for up-scaling and enhancement of resilience in the flood prone regions of Bangladesh. The paper shows a conceptual design for a floating house with six innovation techniques for self-sufficiency and durability. The techniques include wind and flood tolerant structure, vertical gardening, rainwater harvesting, poultry and bio-digester unit, cage fishing, and renewable energy implementation. The techniques are low-tech and cost-efficient. Use of locally available materials enhances the resilience before and after flood. The design presents equality, balance and immense opportunities for the inhabitants. The 3R strategy (reduce, reuse and recycle) is one of the fundamental concepts of this floating house design. The design explores the possibilities of food security, waste management and energy challenge.