The decarbonisation of existing building stocks increasingly depends on renovation, with one-stop shops (OSS) emerging as prominent delivery models designed to reduce complexity and accelerate uptake. However, prevailing renovation strategies remain dominated by performance-oriented paradigms that prioritise modelled energy performance targets and efficiency ratios, understood in energy use per unit of floor area, while often overlooking absolute energy demand, material use and life-cycle emissions. This paper argues that renovation OSS are not neutral facilitators but decision frameworks that institutionalise specific assumptions about renovation ambition, energy demand and system design at early stages of the renovation process. Drawing on a structured synthesis of literature on OSS models and sufficiency, a conceptual framework is developed that links key sufficiency dimensions, space, material, technical and performance sufficiency, to distinct renovation decision stages. Existing OSS practices tend to favour comprehensive renovation scopes, overestimated demand assumptions and performance maximisation, potentially reinforcing system oversizing and unnecessary material intervention. An alternative of embedding sufficiency principles in early-stage assessment, scenario development, system sizing and evaluation criteria can reorient renovation pathways toward proportional and context-sensitive strategies. OSS can be an institutional leverage point for operationalising sufficiency in renovation governance.

Background and aim. Circular economy (CE) practices in the built environment require integrating strategies such as life cycle assessment (LCA), cradle-to-cradle (C2C) principles, stakeholder collaboration, and the 10R framework to enhance resource efficiency and minimize environmental impacts across the entire building. However, existing research lacks a comprehensive framework that systematically combines these elements while demonstrating their practical application and addressing stakeholder alignment in real-world scenarios. This study aims to propose a novel framework that integrates LCA, C2C principles, the 10R framework, and stakeholder engagement to advance CE practices in building renovation.

Methods and Data. By applying a mixed-methods approach, this study combines qualitative and quantitative analyses to evaluate CE strategies. The qualitative analysis involves material suitability for reuse, refurbishment, or storage, and explores stakeholder roles within the 10R and C2C frameworks. The quantitative analysis, based on LCA, measures GHG emissions by comparing two scenarios using new and reused materials, highlighting potential carbon savings. A case study of a single-family building renovation from Sweden illustrates the practical application of these strategies and emphasizes the importance of stakeholder collaboration in overcoming barriers.

Findings. The findings underscore the importance of strategic material selection and the transformative role of material reuse in achieving long-term carbon savings and minimizing GHG emissions. Incorporating reused materials into building renovation p

Urban Building Energy Modelling (UBEM) has become an essential tool for analysis and planning renovation strategies as well as predicting future energy use patterns both at building and district levels. To aid urban planning effectively, digital solutions such as UBEM should support informed urban planning decisions by analysing various renovation scenarios, including energy use, occupant comfort, and climate resilience, while ensuring accuracy without excessive complexity. A critical input for physics-based UBEM tools is building geometry, which can be represented at different levels of detail (LoD). Striking a balance between accuracy and the costs and time required for data generation necessitates examining the influence of LoD in building geometry. This research aims to investigate the extent to which the LoD in building geometry can influence the accuracy of results. To achieve this, four LoD of building geometry were defined for 9 different detached single-family houses in Sweden, and their effect on model performance was assessed with and without calibration using the Monte Carlo Markov Chain (MCMC) algorithm. The calibration used simulated heating demand and utility bill data, optimising for Coefficient of Variation of the Root Mean Square Error (CVRMSE) and Normalised Mean Bias Error (NMBE) indices. The results indicate that, without calibration, models with differing geometric LoDs can exhibit significant performance discrepancies, with variations of up to 19.7% in the CVRMSE and 22.5% in NMBE observed between high and low geometric detail levels. However with calibration, the differences between models with varying geometric LoDs were substantially reduced, with average CVRMSE and NMBE decreasing to 2.9% and 0.9%, respectively, well within ASHRAE Guideline thresholds. The findings offer useful guidance for academic and societal stakeholders working to improve energy modeling in urban planning. By identifying effective LoDs and calibration methods, this research enables cost-efficient UBEM applications, supporting better decisions for sustainable urban development.

This study compares two renovation strategies for a Swedish single-family home using Attributional and Consequential Life Cycle Assessment (ALCA and CLCA). The first models a deep energy retrofit; the second combines this with spatial sufficiency by converting attic space into an accessory dwelling unit (ADU) to accommodate an additional household. Both scenarios are assessed over a 25-year reference period using harmonized system boundaries and data from Ecoinvent v3.6. ALCA quantifies direct environmental impacts within fixed system boundaries, while CLCA captures systemic effects, including avoided construction and supply chain responses. Results show that the sufficiency scenario increases embodied emissions under ALCA but achieves lower per capita emissions in both approaches and significant avoided impacts under CLCA. The findings illustrate how methodological framing - particularly functional unit choice and system boundary definition - shapes perceived renovation benefits. Integrating sufficiency strategies and occupancy-adjusted metrics into policy and assessment frameworks is critical for aligning building renovation with long-term climate goals.

Buildings have a significant impact on environmental sustainability and resource consumption, highlighting theurgent need for holistic and sustainable approaches within the built environment. This study employs a mixed methods approach, combining focus groups and online surveys to examine the willingness of Single-Family Housing (SFH) owners in Sweden’s Kronoberg Region to adopt space sufficiency interventions during energy renovations and using the Attitude-Behavior-Context (ABC) theoretical framework to identify the factors influencing these decisions. The interventions studied include downsizing, optimizing space use, and converting underutilized areas into smaller living units, aiming to reduce per-capita energy consumption, and decrease both operational and embodied carbon emissions.The findings reveal a low interest among SFH owners in adopting these measures, primarily due to concerns about lifestyle changes, reduced comfort, privacy, status, and property value depreciation. While personal and psychological factors affect adoption, external factors—such as regulatory policies, economic incentives, socialnorms, and technical solutions—create the broader landscape that can either facilitate or hinder the implementation of sufficiency measures. The study also highlights that homeowners with larger, child-free properties are more receptive to sufficiency interventions, suggesting that life stage significantly influences readiness for change.The study calls for a systemic approach that promotes behavioral, normative, and cultural shifts through comprehensive regulations, policies, and incentives, creating the necessary conditions for broad adoption. Tailored design proposals and support structures, such as One-Stop Shop (OSS) models, are crucial in guiding homeowners through the transition. Government involvement is essential in establishing the frameworks needed to drive sufficiency, transforming homes from static to dynamic structures that evolve with changing householdneeds. Promoting flexible design, innovative policies, and financial incentives is vital for increasing adoption,with early adopters playing a pivotal role in accelerating market acceptance.

The increasing urbanization and influx of people into cities urge the need for sustainable living solutions, pressing on natural resources and environmental sustainability. This study explores how integrating principles of sufficiency and adaptability to varying occupant needs can enhance the adequacy and optimization of space and resource consumption. Building upon an integrative review of existing literature, it investigates these concepts' interconnectedness within the built environment, aiming to clarify adaptability's potential in facilitating space-sufficiency interventions.

A synergetic linkage of the principles of adaptability and sufficiency in buildings is needed to adapt to evolving needs and reduce environmental impacts. Such an approach stresses a user-focused strategy and views buildings as dynamic systems capable of adapting to technological changes, environment, and society. This manuscript leverages an integrative literature review to propose a conceptual framework to enhance building space utilization.

Drawing inspiration from the 5R Hierarchy, traditionally applied to waste management, it reimagines underutilized space as a form of waste, suggesting intervention steps such as rethinking, reducing, reusing, and repurposing. These steps target spatial rearrangements to tackle the complexities of space optimization.

Aligned with the "Intervention Steps," a series of Key "Intervention Parameters" are outlined to boost the effectiveness of interventions across Shearing Layers, considering the immediate and future needs of occupants. This framework provides a strategic approach to managing space and promoting environmental sustainability and occupant well-being effectively, with the potential to yield economic and social advantages in built environments. The proposed “Intervention” Framework is based on an extensive literature review, but real-world applications are needed to refine and validate this approach. Further exploration is necessary to identify regulatory and policy frameworks to facilitate and incentivize its implementation.

The increasing urbanization and influx of people into cities urge the need for sustainable living solutions, pressing on natural resources and environmental sustainability. This study explores how integrating principles of sufficiency and adaptability to varying occupant needs can enhance the adequacy and optimization of space and resource consumption. Building upon an integrative review of existing literature, it investigates these concepts’ interconnectedness within the built environment, aiming to clarify adaptability’s potential in facilitating space-sufficiency interventions. A synergetic linkage of the principles of adaptability and sufficiency in buildings is needed to adapt to evolving needs and reduce environmental impacts. Such an approach stresses a user-focused strategy and views buildings as dynamic systems capable of adapting to technological changes, environment, and society. This manuscript leverages an integrative literature review to propose a conceptual framework to enhance building space utilization. Drawing inspiration from the 5R Hierarchy, traditionally applied to waste management, it reimagines underutilized space as a form of waste, suggesting intervention steps such as rethinking, reducing, reusing, and repurposing. These steps target spatial rearrangements to tackle the complexities of space optimization. Aligned with the “Intervention Steps,” a series of Key “Intervention Parameters” are outlined to boost the effectiveness of interventions across Shearing Layers, considering the immediate and future needs of occupants. This framework provides a strategic approach to managing space and promoting environmental sustainability and occupant well-being effectively, with the potential to yield economic and social advantages in built environments. The proposed “Intervention” Framework is based on an extensive literature review, but real-world applications are needed to refine and validate this approach. Further exploration is necessary to identify regulatory and policy frameworks to facilitate and incentivize its implementation.

Residential energy consumption remains a significant driver of CO2 emissions in European buildings, demanding urgent action in the face of the climate crisis. While prevailing efforts have predominantly concentrated on enhancing energy efficiency and integrating renewable sources, addressing the climate urgency and resource constraints necessitates a paradigm shift towards sufficiency principles. Swedish statistics on Single-Family Houses (SFH) show that more than a third of households inhabit oversized spaces in aging buildings needing renovation. Sufficiency-oriented renovation strategies—optimizing, or reducing living areas per capita— present a promising avenue to achieve substantial energy reductions. This approach also opens the potential for space rentals, yielding combined energy and space efficiency advantages. In addition, the literature highlights reduced maintenance costs and potential urban housing crisis mitigation. However, practical implementation faces multiple obstacles.This paper investigates SFH owners' attitudes towards space-sufficiency interventions, focusing on living size preferences and identifying barriers and opportunities for sustainable housing. Through focus group sessions with SFH owners in November-December 2022, qualitative content analysis revealed that reducing living space per capita faces multifaceted challenges, despite potential benefits.These challenges encompass not only personal and psychological considerations but extend to economic, infrastructural, and policy barriers, including issues such as the potential breach of privacy, disruptions due to noise, dilemmas related to ownership and independency, disruptions to work-life dynamics, inadequate familiarity with sufficiency principles, and uncertainty imposed by space constraints. Strategic integration of sufficiency principles into energy-renovation policy alternatives necessitates a holistic approach that addresses these barriers, and some form of incentives may be needed to catalyze the adoption of sufficiency principles effectively.

In Northern Europe, Single Family Housings (SFH) constitute a large share of the total building stock. In Sweden, more than 52% of the population lives in SFH. Most of these houses were built between 1960-80 and are currently needing renovation. Most of these houses are owned by older adults whose kids have moved away, and thus they live in housing over-dimensioned to their needs with a large share of energy consumption for space heating. Furthermore, these facilities are neither elderly-friendly nor energy-efficient, deeming major renovation.

 This paper applies a case-study approach to explore options to better utilize and reduce the living area per capita through the generation of Additional Dwellings Unit (ADU) within the existing building stock owned by the elderly. The case study SFH owned by an elderly couple is located in Kronoberg Region, Sweden, and is a typical SFH built during the 1970s. We redesign and restructure the underused space to create an ADU that can be rented out, which in turn may economize the high investment costs of energy-efficient renovation. The energy efficiency renovation measures considered were improvement of the building's climate shell (envelope), extra insulation in the walls and attic, and better performance doors and windows. Energy simulations and life cycle cost assessment of the energy efficiency measures, and space redesign showed that it is possible to reduce energy use by 61% compared to the existing condition of the reference house and a payback time of 59% compared to the application of the energy measures alone. The proposed intervention is aligned with the aging in place strategy, tackling it from a space sufficiency perspective. The proposed intervention reduces the living space per resident by 40% and energy consumption per capita by 62% compared to just the energy renovation of the reference house while creating cash inflows that motivate the houseowner to uptake an energy renovation. The improved energy performance of the building may generate better indoor living conditions for a healthier life for the residents.

Sweden's shortage of affordable housing has been evolving into a major in recent years. A 2021 report by the Swedish National Board of Housing, Building, and Planning (Boverket) stated a need for 60,000 new homes by 2030. In addition, the Swedish building stock is responsible for 39% of the country's total energy consumption and 21% of its greenhouse gas emissions. Therefore, solutions to address the housing crisis should go hand in hand with the need for increased building retrofits to meet Sweden's 2045 energy and climate targets. In this context, re-densification of the existing building stock is a possible option. This study examines possible space- and energy-efficient options for densifying the housing supply in Sweden's existing single-family home (SFH) segment. Using a case study in Kronoberg, Sweden, occupied by an elderly household, options for converting the unused space into new additional dwelling units (ADUs) and reducing per capita living space are explored. Most SFHs in Sweden are old, in poor condition, and in urgent need of structural and energy retrofits. In addition, about one-third of homeowners are over 60 years old and report living in homes that are too large compared to their needs - an excellent environment to study the proposed intervention. Revenues from renting the newly created ADUs suggest that the proposal is financially attractive because it capitalizes on the high initial investment costs of energy retrofits. In addition, spatial interventions combined with energy-efficient measures result in a 40 percent lower energy use and environmental impact per capita compared to energy retrofits alone due to a reduction in per capita living space. Finally, the study aims to initiate a discussion on sufficiency, innovative energy regulations, and housing policy tools needed to transition to the low-energy single-family housing stock