Search Results (133)

The building sector significantly contributes to global energy consumption and carbon emissions, primarily due to the extensive use of carbon-intensive materials such as concrete and steel. Mass timber construction, particularly using cross-laminated timber (CLT), offers a promising low-carbon alternative. This study aims to calculate the embodied carbon emissions and biogenic carbon storage of a CLT-based affordable housing project, 340+ Dixwell in New Haven, Connecticut. This project was designed using a honeycomb structural system, where mass timber floors and roofs are supported by mass timber-bearing walls. The authors are not aware of a prior study that has evaluated the life cycle impacts of honeycomb mass timber construction while considering Timber Use Intensity (TUI). Unlike traditional post-and-beam systems, the honeycomb design uses nearly twice the amount of timber, resulting in higher carbon sequestration. This makes the study significant from a sustainability perspective. This study follows International Standard Organization (ISO) standards 14044, 21930, and 21931 and reports the results for both lifecycle stages A1–A3 and A1–A5. The analysis covers key building components, including the substructure, superstructure, and enclosure, with timber, concrete, metals, glass, and insulation as the materials assessed. Material quantities were extracted using Autodesk Revit^®, and the life cycle assessment (LCA) was evaluated using One Click LCA (2015)^®. The A1 to A3 stage results of this honeycomb building revealed that, compared to conventional mass timber housing structures such as Adohi Hall and Heartwood, it demonstrates the lowest embodiedf carbon emissions and the highest biogenic carbon storage per square foot. This outcome is largely influenced by its higher Timber Use Intensity (TUI). Similarly, the A1-A5 findings indicate that the embodied carbon emissions of this honeycomb construction are 40% lower than the median value for other multi-family residential buildings, as assessed using the Carbon Leadership Forum (CLF) Embodied Carbon Emissions Benchmark Study of various buildings. Moreover, the biogenic carbon storage per square foot of this building is 60% higher than the average biogenic carbon storage of reference mass timber construction types. Full article

In promoting sustainable cities and societies, accelerating the shift from sustainable building design to sustainable building operations is essential. A persistent challenge lies in the absence of a unified, multidimensional metric that enables meaningful performance comparisons across buildings of similar types and functions, both regionally and globally. This study develops and demonstrates the operational sustainability index (OPSi)—a novel metric grounded in case study research that integrates indoor environmental quality (IEQ) and energy utility quality (EUQ). OPSi is applied to six buildings in three comparative cases: (1) LEED-certified and non-certified dormitories, (2) LEED-certified and non-certified event buildings, and (3) male- and female-occupied multifamily housing units. Results show that the LEED-certified dormitory underperformed in two of five OPSi variants compared to its non-certified counterpart despite achieving up to 18% higher objective IEQ performance. The LEED-certified event building outperformed its non-certified counterpart across all OPSi metrics, with up to 88% higher objective IEQ scores. Findings also include higher energy performance in male-occupied housing units than in female-occupied ones, highlighting behavioral differences worthy of future study. This research addresses longstanding criticisms of green certification systems—particularly their limited capacity to holistically measure post-certification operational performance—by offering a practical and scalable evaluation framework. OPSi aligns with global sustainability goals, including SDG 11 (Sustainable Cities and Communities) and SDG 7 (Affordable and Clean Energy), and supports smart, data-driven decision-making. Future applications may extend OPSi to include carbon life cycle assessment and maintenance metrics to further strengthen building sustainability in urban contexts. Full article

Residents in low-income multifamily housing often struggle to afford energy for essential needs such as heating, cooking, and electronics. Climate change may increase these energy demands, and high energy bills can reflect inefficiencies in a home’s systems or envelope. Improving the energy efficiency in low-income housing benefits both social justice and sustainability. However, there is limited information on the impact of energy upgrades in multifamily settings. This study examined the energy-related experiences of low-income families in public housing in Detroit, Michigan, who received energy-conserving measures (ECMs) such as efficient light bulbs, faucets, thermostats, and refrigerators in 2022. Thirty-nine residents completed surveys and provided energy usage data before and after the upgrades; twelve residents provided their hourly energy usage. Over 90% of residents reporting income information had an energy burden exceeding 6%, with higher energy expenses during colder months. While many residents appreciated the upgrades, quantitative evidence of reduced energy burdens was insufficient. Existing utility programs for multifamily residents typically offer minor upgrades but do not include larger appliance replacements or improvements to home insulation. To maximize energy efficiency for low-income families, thus promoting sustainability, more comprehensive programs and retrofits are necessary. Full article

Focusing on issues related to SDG 11 (Sustainable Cities and Communities) and SDG 13 (Climate Action), this study aligns with the framework of the 2030 Agenda for Sustainable Development. This study explores the barriers unique to the industry that obstruct the adoption of low-carbon emission solutions in Jordan’s multi-family residential buildings. Multi-family apartments constitute 73% of the total housing stock and account for over 80% of all residential structures. A total of eight main barriers that are preventing the implementation of low-carbon emission techniques were evaluated. The Fuzzy Delphi Method was utilized to gather insights from the Consultancy Council members of the Jordan Housing Investors Association. The results suggest that a major obstacle is the insufficient knowledge among end-users regarding environmental concerns, along with financial limitations, resulting in a lack of enthusiasm for low-carbon multi-family apartments. Moreover, insufficient cooperation between consultants and contractors leads to subpar constructability, which is worsened by the prevailing conventional procurement method that prioritizes cost and schedule above environmental consequences. To further investigate, it is advisable to examine the utilization of contemporary procurement methods, such as Design–Build and Construction Management and modern family contracts such as NEC4 in the housing industry of Jordan. These alternative methods have the potential to solve the current difficulties by promoting more effective and environmentally friendly building practices. Full article

Food waste is a significant global issue with substantial environmental, economic, and social implications. This exploratory study aimed to evaluate the impact of an educational composting program on reducing food waste generation and promoting proper waste sorting practices within multi-family housing units in San Marcos, Texas. A comprehensive methodology was employed, encompassing pre- and post-intervention waste audits, educational interventions, weekly organic waste collection, and quantitative data analyses. Nine multi-family complexes, spanning student housing, conventional family units, low-income residences, and senior living facilities, were targeted through strategic recruitment efforts and incentivization. The treatment group, consisting of 43 participants, received ongoing education throughout the eight-week implementation period, facilitated through informational resources, feedback mechanisms, and door-to-door organic waste collection. Conversely, the control group did not partake in the educational component. Statistical analyses, including descriptive statistics and paired t-tests, facilitated comparisons across various dimensions, such as housing types, treatment versus control groups, and pre- versus post-intervention periods. The findings revealed significant reductions in organic waste and compostable materials within the treatment group’s weekly landfill trash, underscoring the effectiveness of the educational program. Furthermore, insights into contamination patterns and housing-specific waste characteristics were garnered, informing targeted intervention strategies and policy recommendations for optimizing multi-family composting initiatives. Full article

Mitigating carbon dioxide emissions in the building sector is a primary global goal. This paper compares different residential buildings in urban and rural regions of Hajdú-Bihar County (Hungary). Significant differences were found between urban and rural single-family houses concerning their energy performance; however, the differences in CO₂ emissions were not significant. Only the differences in specific heat losses were significant between urban single-family and masonry-structured multifamily buildings. Panel buildings demonstrate the best energy performance from their construction period, but due to high investment costs and the inability to change the heat source, the CO₂ emissions from these buildings have a lower limit today. In both single-family houses and masonry-structured multifamily buildings, meeting the heat demand can be achieved with zero CO₂ emissions using existing technologies. Full article

South Korea is rapidly transitioning into an aging society, resulting in a growing demand for senior multi-family housing. Nevertheless, current façade designs remain limited in diversity and fail to adequately address the visual needs and preferences of the elderly population. This study presents a biophilic façade design approach for senior housing, utilizing Stable Diffusion (SD) fine-tuned with low-rank adaptation (LoRA) to support the implementation of differentiated biophilic design (BD) strategies. Prompts were derived from an analysis of Korean and worldwide cases, reflecting the perceptual and cognitive characteristics of older adults. A dataset focusing on key BD attributes—specifically color and shapes/forms—was constructed and used to train the LoRA model. To enhance accuracy and contextual relevance in image generation, ControlNet was applied. The validity of the dataset was evaluated through expert assessments using Likert-scale analysis, while model reliability was examined using loss function trends and Frechet Inception Distance (FID) scores. Our findings indicate that the proposed approach enables more precise and scalable applications of biophilic design in senior housing façades. This approach highlights the potential of AI-assisted design workflows in promoting age-inclusive and biophilic urban environments. Full article

Improving residential energy efficiency is essential for optimizing energy consumption. This article analyzes the electricity and natural gas consumption of a benchmark multi-family housing model in Algiers, based on data from 295 residential units collected over three consecutive years (2022, 2023, and 2024). A comprehensive approach combining data visualization, statistical analysis, a clustering approach, a tariff structure assessment, and an energy performance index is applied to assess residential energy-consumption trends. The findings reveal opposing trends between electricity and natural gas consumption. The electricity demand increased steadily (+15% from 2022 to 2024), particularly in the third trimester (summer), where 40% of the housing unit consumption exceeded 1000 kWh per trimester, indicating a growing reliance on air conditioning. In contrast, natural gas consumption declined significantly, with winter usage dropping by more than 20%, suggesting improved heating efficiency, better thermal insulation, and/or milder weather conditions. The clustering analysis also highlights a shift toward more homogenous consumption profiles, with fewer outliers and a narrower interquartile range, indicating greater energy efficiency across households. The results underscore the need for adaptive energy pricing policies and targeted household awareness programs. They further suggest that incentive-based measures, particularly during peak summer periods, could mitigate demand spikes and enhance energy system resilience. The energy benchmarking approach developed in this study can support decision-makers in adjusting tariff structures according to household energy profiles to improve overall energy efficiency. Full article

The outdoor climate is expected to undergo significant and extreme changes. These changes may lead to increased building requirements depending on their location. This is critical, as human beings tend to spend a large part of their time inside buildings. Accordingly, it is crucial to take future conditions into account to ensure an adequate indoor climate, simultaneously meeting the current drive for decarbonization of the built environment. One avenue is opting for thermally efficient building products and technologies with a lower carbon footprint to guarantee a comfortable indoor climate while minimizing energy consumption. This study focuses on the Northeast region of Brazil, specifically its nine states, given the usage of specific passive thermal strategies in new buildings that have high compensatory energy consumption. This is achieved through developing computational thermal models of a housing unit in a multi-family building, commonly constructed in several cities in this region. This thermal model was employed to analyze indoor thermal comfort, energy consumption, and carbon footprint. To account for future climate projections, the analysis includes scenarios based on Representative Concentration Pathways 4.5 and 8.5. The efficiency of certain sustainable passive rehabilitation is demonstrated in this region, highlighting the importance of adopting passive and efficient thermal measures appropriate to the region’s climate. Full article

Energy-efficient renovation of the existing building stock is essential for achieving the ambitious sustainability goals set by the European Commission for 2030. However, implementing sustainable renovation has proven challenging, as numerous studies have concluded. Multi-family buildings are a significant part of Sweden’s building stock and require renovations to meet energy efficiency standards. This study aims to provide an overview of sustainable renovation practices in Sweden’s multi-family buildings. A semi-open structured questionnaire was developed to examine the adoption of these practices, with data collected from 11 housing companies. The responses reveal that Swedish housing companies are well aware of the three key aspects of sustainability and actively consider them in their renovation projects. Notably, specific energy use and investment costs are the most commonly used methods for evaluating the environmental and economic aspects, respectively. However, there is a lack of a common method for assessing the social aspects of renovation projects. Additionally, this study highlights the need for standardized decision-making tools in multi-family building renovations. Full article

The residential sector accounts for over a third of the world’s energy use. Even though this ratio is lower in Mexico, there is a pressing housing deficit, especially regarding low-cost homes. This research aimed to create a reference building (RB) to understand the current energy consumption of multi-family buildings across different climatic zones. The aim was to assess their energy performance and promote reduced energy requirements as a guideline for designing and constructing affordable, low-energy, or zero-energy buildings. The present work conducts a diagnosis of the current energy consumption of multi-family buildings in eight cities in Mexico. First, a reference building was developed to represent typical Mexican building geometry and construction practices, and then the building’s fixed and variable energy requirements were simulated. Finally, a comparison was made between the energy requirement and the data reported by the national energy survey. Therefore, it was possible to generate a reference building from national data sources complying with national regulations, where materials, occupant behavior, and equipment were chosen to help represent the building’s thermal behavior. Domestic water heating was identified as a driver of variable energy requirements in all cities. In contrast, the simulated heating and cooling requirements were directly linked to the city’s climate. Electricity bills tended to mostly correspond with the results that excluded the use of heating systems. Lastly, while comparing LPG (Liquified Petroleum Gas) consumption was challenging due to the unavailability of national data, LPG requirements were closely estimated for temperate cities. The definition of a reference building is an important step towards developing nZEB in Mexico, as these buildings are valuable tools that can contribute to the energy evaluation of specific types of buildings. This characteristic makes them convenient for revising a building code or setting new national energy policy goals. Full article

Rainwater harvesting has been widely discussed globally due to major concerns regarding climate change and water scarcity. This paper aims to analyse and evaluate rainwater harvesting in buildings and its relationship with the water–energy nexus. Five types of buildings were analysed: public, industrial, commercial, single-family houses, and multi-family residential buildings within the Cubatão do Norte river watershed in Joinville, Brazil. Using simulations in the Netuno programme, the potential for potable water savings was calculated. This potential was compared to the energy consumption for potable water treatment by the municipality. The average potential for potable water savings was the following: 28.18% for public buildings, 50.83% for industrial buildings, 34.12% for commercial buildings, 23.12% for single-family houses, and 18.55% for multi-family residential buildings. After analysing the energy savings for the entire watershed, the average savings were 245 kWh/day for all public sector buildings, 209 kWh/day for all industrial sector buildings, 8 kWh/day for all commercial sector buildings, 25 kWh/day for all single-family houses, and 15 kWh/day for all multi-family residential buildings. Over a year, energy savings can range from 135,426 kWh to 240,900 kWh in all the buildings studied in Joinville. Finally, further studies on the water–energy nexus are needed to make cities more resilient and sustainable in terms of using resources. Full article

The implementation of photovoltaic and home storage systems in multi-family houses (MFHs) in Germany lags significantly behind their development in single-family houses. The Landlord-to-Tenant (L2T) power supply model is meant to reduce this gap, yet few projects have been implemented to date. In this model, the landlord must fulfill the tenants’ power demand through a combination of photovoltaic generation and storage and electricity from the grid, for which the landlord pays an auxiliary electricity price that greatly influences the financial viability of a project. Our contribution focuses on the impact of electricity price variations and recent policy changes on the financial viability of small-scale L2T concepts. We considered component investment costs, building sizes, photovoltaic yields, and future developments. Recent policy changes have improved the financial viability of L2T projects, increasing the maximal auxiliary electricity price for which an investment is viable by 13 ct/kWh for a four-party MFH. Minimal auxiliary electricity prices justifying the installation of home storage systems (HSSs) decreased by 9 ct/kWh from 2020 to 2023. Autarky rates are substantially different across the considered scenarios, with the autarky rate being defined as the percentage of consumption of self-generated energy relative to the total energy consumption. For a 22-party MFH the autarky rate decreases by 17% compared to a 4-party MFH. HSSs have the potential to increase autarky rates while maintaining the financial viability of L2T projects. Full article

Rainwater harvesting (RWH) has emerged as a promising technique to improve water security amid the escalating effects of climate change. However, a comprehensive evaluation of various rainwater harvesting solutions is needed to promote sustainable practices in the building sector. This study aims to evaluate the water saving potential in multi- and single-family social housing buildings in twelve cities in Brazil. Computer simulations were performed for 60 scenarios, comprising five social housing reference models and using rainfall data from twelve representative cities of Brazil’s bioclimatic zones. The results show that single-family houses presented a higher potential for potable water savings (20 to 22%) than multi-family housing models (2 to 3%), mainly due to their higher roof-area-to-resident ratio. Single-family buildings exhibit more significant variability in absolute savings (standard deviation), while multi-family buildings are more sensitive to variability relative to their means (higher CVs). Furthermore, due to uneven rainfall distribution and storage limitations, water savings potential does not correlate linearly with total annual rainfall. Normalised results reveal that buildings with a lower population density achieve higher water savings per area and inhabitant. This study demonstrated that building and climate characteristics influence rainwater harvesting, offering valuable insights for promoting sustainable water management practices in social housing. Full article

The European climate change mitigation agenda aims to decarbonise all buildings by 2050. However, many existing buildings may not remain operational by this time due to rapid urbanisation and population decline in various regions of Europe, potentially leading to the abandonment of residential properties. The current EU renovation strategies often overlook the future of legacy buildings. The challenge lies in identifying which buildings are likely to become unserviceable and, therefore, unsuitable for significant energy efficiency upgrades. This study proposes the use of domestic consumption metering as a universal vacancy indicator to determine the actual underused dwellings in multifamily buildings. Our case study demonstrates that population registry-based datasets consistently overestimate vacancy rates when compared to the evidence provided by consumption metering data. Consumption-based vacancy rates exceeding 20 percent are associated with an unlikelihood of energy renovations, thereby impeding the aims of the energy efficiency transition. Spatial analysis reveals that vacancy rates increase as the distance from the regional centre to the building grows. This correlation indicates the presence of shrinking hinterlands and highlights the need to consider to what extent such regions should be targeted by incentives for energy renovations. We recommend utilising this vacancy indicator to estimate energy renovation scenarios in policymaking. Full article