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Department: Architecture

Material use and embodied carbon from new construction buildings in North America: Analysis and projection to 2050

Ashtiani, M., Benke, B., Shen, Y., Jungclaus, M., Lewis, M., Rempher, A., Esau, R., & Simonen, K. (2026). Material use and embodied carbon from new construction buildings in North America: Analysis and projection to 2050. Journal of Building Engineering, 130, Article 116959. https://doi.org/10.1016/j.jobe.2026.116959

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Abstract

Buildings are a major consumer of raw materials and emitter of greenhouse gases (GHGs), yet data on their resource use and embodied environmental impacts remain limited. This study investigates the material use intensity (MUI) and embodied carbon intensity (ECI) of new construction commercial and multifamily residential buildings in North America using data from 239 building life cycle assessment (LCA) models. This study develops a benchmark data analysis framework to provide MUI and ECI values, defined in units of mass and embodied carbon per building floor area, across different building typologies, structural systems, and material categorizations. Results show a wide variability in building-level MUI (269-2860 kg/m2) and ECI (115-1030 kgCO2e/m2) within A1-A3 LCA modules. The study also establishes material-level MUIs and ECIs, highlighting that concrete, steel, gypsum, masonry, and wood and composites account for more than 96% of the mean MUI, while concrete, steel, insulation, aluminum, and applied fireproofing account for more than 80% of the mean ECI across all buildings. Using a bottom-up approach, future material consumption and embodied carbon emissions for new construction buildings in the US from 2020 to 2050 were projected to establish a business-as-usual (status quo) baseline under constant-intensity assumptions. Concrete and steel remain the largest contributors to embodied carbon of buildings in 2050, accounting for 38% and 24% of total emissions, respectively. Findings indicate that effective building decarbonization requires concurrent accounting of material use and embodied carbon at both building and material levels. The study calls for standardized material-level analysis methods to improve comparability across studies and support data-driven decarbonization policies and practices. Methods and results are shared as open-access code and an interactive visualization dashboard to support reuse and transparency.

Keywords

Embodied carbon; Material use; Life cycle assessment; Building; Projection; Benchmark

A review of building-scale LCA tools: recent trends, gaps and future directions

Torabi, M., Huang, M., Evins, R., & Simonen, K. (2026). A review of building-scale LCA tools: recent trends, gaps and future directions. Journal of Building Performance Simulation, 1–28. https://doi.org/10.1080/19401493.2026.2663472

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Abstract

This study reviews active building-scale LCA tools in North America to evaluate how effectively they support the transition toward net-zero and carbon-negative design. A structured Characterization Framework was developed through a targeted literature review and stakeholder input to identify key features that enable low-carbon building design. Thirteen continuously updated and widely used tools were analyzed to assess trends, gaps, and opportunities. The results reveal positive developments such as greater self-sufficiency through embedded defaults, expanded life-cycle scope, and enhanced user control. However, significant gaps persist, including limited treatment of carbon sequestration, dynamic climate modeling, and novel material integration, as well as inconsistent data, simplistic scenarios modeling and limited functionality for early-stage design. Overall, while building LCA tools are becoming more transparent and flexible, advancing time-sensitive impact modeling, carbon sequestration accounting, and interoperability with design workflows will be essential to achieve more accurate, consistent, and forward-looking assessment that enable carbon-positive building practices.

Keywords

Building LCA tool; Carbon sequestration; Carbon reduction; Life cycle assessment; Tool review

 

Tool Requirements for Life Cycle Assessment in the Innovation of Novel Carbon-Storing Construction Materials

Huang, M., Ellingboe, E., Lin, M.-Y., Echenagucia, T. M., & Simonen, K. (2026). Tool Requirements for Life Cycle Assessment in the Innovation of Novel Carbon-Storing Construction Materials. Applied Sciences, 16(8), 4040. https://doi.org/10.3390/app16084040

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Abstract

Novel carbon-storing construction materials have the potential to reduce greenhouse gas emissions by removing carbon dioxide from the atmosphere and storing it in long-lived building products. In order to understand the full benefits and shortcomings of carbon-storing materials, life cycle assessments (LCAs) must be performed. However, material innovators who are looking to perform LCAs of their products during early-stage research and development (R&D) face many challenges. While these challenges have been reported in the literature, this information has been fragmented and required a more comprehensive investigation. We explored these LCA challenges by holding an in-person workshop with sixteen R&D teams who were developing carbon-storing materials and building designs. From the data collected in this workshop, we found that the R&D teams struggled with data availability, biogenic carbon, and uncertainty, which confirmed our findings from the literature. They also struggled with various other LCA topics. Since current LCA tools lack functions that would be useful for this user group, we also proposed a list of tool ideas that could address their LCA needs, which can inform future LCA tool development.

Keywords

LCA; sustainability; early-stage; low-carbon; R&D; workshop

A Proxy Method to Bridge LCA Data Gaps Using Automated Material Classification and Probabilistic Under-Specification

Ellingboe, E., Huang, M., Sultana Priyota, A., & Simonen, K. (2026). A Proxy Method to Bridge LCA Data Gaps Using Automated Material Classification and Probabilistic Under-Specification. Environmental Science & Technology, 60(16), 12268–12279. https://doi.org/10.1021/acs.est.5c12282

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Abstract

Life cycle assessments (LCAs) are essential for understanding the environmental impacts of material production. However, gaps in life cycle inventory (LCI) data for material and chemical inputs present a key challenge for LCA practitioners, especially in the early design stages. Strategies for filling in these gaps require additional time and expertise, which can hinder the LCA’s completion. This study combined automatic material classification and probabilistic under-specification to create a time-efficient method to fill material LCI data gaps. To illustrate the proposed method, proxy environmental impact distributions were generated using publicly available material LCI data classified into the ChemOnt chemical taxonomy using the open-source chemical classification software ClassyFire. Input materials with data gaps were then classified into the same taxonomy, where proxy environmental impact values could be selected from the available distributions to quickly fill in any data gaps. Although these methods were applied to classify material production processes available in the Federal LCA Commons and Ecoinvent databases, they can be applied to any LCA database. This study shows that classifying materials by their chemical structure produces taxonomies with increased granularity relative to industrial classification, improving the ability of under-specified proxy data to be used for differentiating the environmental impacts of competing designs.

Keywords

Life Cycle Assessment; Data Gap; Proxy Data; Chemical Classification; Novel Materials; Probabilistic Under-Specification

Exploratory Data Analysis of a North American Whole Building Life Cycle Assessment datasets

Shen, Y., Benke, B., Ashtiani, M., Huang, M., & Simonen, K. (2025). Exploratory Data Analysis of a North American Whole Building Life Cycle Assessment datasets. Building and Environment, 286, Article 113655. https://doi.org/10.1016/j.buildenv.2025.113655

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Abstract

The building construction sector is a major contributor to global greenhouse gas emissions, with embodied carbon—the emissions from material production, use, and disposal—forming a significant portion. While whole building life cycle assessment (WBLCA) quantifies such impacts, detailed statistical analysis for interpretation of WBLCA data remains underutilized. This study addresses the gap by introducing a systematic exploratory data analysis (EDA) framework applied to a harmonized and high-resolution dataset of 244 real-world North American buildings. The core steps in the EDA framework include distinguishing attributes, univariate analysis, bivariate analysis, and feature engineering. These steps address the different data challenges, such as high dimensionality, mixed attribute types, missing values, outliers, and multivariate relationships through the evaluation of robust selections of statistical methods in EDA. Bivariate analysis (e.g., mutual information, one-way ANOVA, post-hoc analysis, and two-way ANOVA) and feature engineering methods quantified the correlation and differences in pairwise and global relationships. Embodied carbon intensity weakly correlated with most meta-features, while materials and building use emerged as the most influential factors. Given that the dataset is uniquely comprehensive and disaggregated, a more nuanced and detailed understanding of environmental impact patterns and relationships is possible. This research demonstrates that following the systematic EDA framework provides a well-defined process to address the database challenges. Its integration into WBLCA dataset evaluation enhances interpretation and supports informed decision-making for low-carbon building design and decarbonization strategies that a conventional simplified analysis would miss. Moreover, it helps to build the insights necessary for advanced analysis and predictive modeling.

Keywords

Life cycle assessment; Whole building life cycle assessment; Embodied carbon; Data analysis; Exploratory data analysis; Statistical analysis; Building decarbonization

BRE-X Emissions Database for End-of-Life Scenarios of Selective Building Construction Materials to Enable Circular Economy in Construction

Muthumanickam, N. K., Atnoorkar, S., Goetsch, H., Deru, M., Palmeri, J., Ashtiani, M., Hasik, V., & Farnetani, M. (2025). BRE‐X Emissions Database for End‐of‐Life Scenarios of Selective Building Construction Materials to Enable Circular Economy in Construction. Journal of Advanced Manufacturing and Processing, 7(3). https://doi.org/10.1002/amp2.70018

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Abstract

In the United States, construction and demolition debris predominately end up in landfills with minimal end-of-life Re-X (recover, recycle, reuse, etc.) scenarios, resulting in large environmental impacts and lost opportunities for material recovery. Except for concrete and metals, which seem to have a few well-defined end-of-life pathways, there seems to be a lack of well-documented end-of-life scenarios for other construction materials, let alone their emissions data. Hence, there is a need for documented end-of-life Re-X scenarios and end-of-life data of more building materials to motivate widespread use of Re-X strategies in building design. This paper outlines the efforts of the National Renewable Energy Laboratory, Carbon Leadership Forum, Building Transparency, and Skidmore, Owings & Merrill to (a) create an open-access BRE-X (Building Re-X) end-of-life emissions database consisting of greenhouse gas emissions data associated with various end-of-life scenarios for a select list of high-impact building construction materials, and (b) integrate the BRE-X end-of-life emissions database with CAD/BIM/LCA tools for evaluating various end-of-life scenarios. The paper also presents a few existing life cycle inventory databases that contain sparse amounts of end-of-life data for a few construction materials and their limitations in terms of scaling and data consolidation. Finally, a sample of how the collected data can be ingested into whole-building LCA tools using open data formats and a public access link to the BRE-X end-of-life emissions database is also included.

A Harmonized Dataset of High-Resolution Embodied Life Cycle Assessment Results for Buildings in North America

Benke, B., Chafart, M., Shen, Y., Ashtiani, M., Carlisle, S., & Simonen, K. (2025). A Harmonized Dataset of High-Resolution Embodied Life Cycle Assessment Results for Buildings in North America. Scientific Data, 12(1), Article 1085. https://doi.org/10.1038/s41597-025-05216-0

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Abstract

Building design practitioners are increasingly using life cycle assessment (LCA) to assess the environmental impacts of their buildings. However, industry-generated LCA results are rarely compiled into comparable datasets and rarely made public. Thus, harmonized and open-access datasets of building LCA results are limited, particularly in North America. Here we present a novel high-resolution dataset of building design characteristics, life cycle inventories, and environmental impact assessment results for 292 building projects in the United States and Canada. The dataset contains harmonized and non-aggregated LCA model results across life cycle stages, building elements, and building materials to enable detailed analysis, comparisons, and data reuse. It includes over 90 building design and LCA features to assess distributions and trends of material use and environmental impacts. Uniquely, the data were crowd-sourced from designers conducting LCAs of real-world building projects. This dataset fills critical gaps for the building industry, research, and policy communities, enabling them to analyze and compare the impacts of buildings, test or set performance targets, and motivate sustainable design and construction practices.

A novel whole-life carbon assessment of thirty buildings in California

Shen, Y., Benke, B., Roberts, M., Carlisle, S., Chafart, M., & Simonen, K. (2025). A novel whole-life carbon assessment of thirty buildings in California. Journal of Building Engineering, 110, Article 113074. https://doi.org/10.1016/j.jobe.2025.113074

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Abstract

Reducing whole-life carbon emissions from buildings is essential to achieving global climate targets. While many studies exist, few focuses on whole-life carbon assessment at the U.S. state level, such as California, which has strict decarbonization goals and a rapidly evolving policy landscape. To address this gap, we introduce a novel framework encompassing data collection, preparation, carbon calculation, whole-life assessment, and methodological variation analysis—based on data from industry professionals for thirty real buildings in California. To address inconsistency issues among data, a structured data entry template and user guide were developed and data preprocessing and alignment methods were proposed. Finally, the whole-life carbon and temporal relationship of embodied and operational carbon were quantified. Whole-life carbon intensity (WLCI) ranged from 232-2230 kg CO2e/m2, with embodied carbon intensity (ECI) between 192 and 685 kg CO2e/m2 and operational carbon intensity (OCI) from 13 to 1710 kg CO2e/m2. Median values for ECI, OCI, and WLCI were 385, 228, and 734 kg CO2e/m2, respectively. This highlights that embodied carbon constituted a substantial share of total emissions, often exceeding operational carbon, which varied more due to energy sources. The analysis showed modules A1-A3, structural systems, and concrete/metals as major contributors to embodied carbon, with interiors also adding significant emissions. Methodological variations in whole-life carbon assessment were noted, particularly concerning grid decarbonization scenarios, floor area normalization, and energy data sources. Although developed for California, the methods and framework for whole-life carbon assessment are broadly applicable to global contexts.

Keywords

Whole-life carbon assessment; Operational carbon; Embodied carbon; Building life cycle assessment; Data collection; Decarbonization

What matters the most in designing low-carbon buildings in Canada? Exploring the tradeoff between embodied and operational carbon in early stage design

Torabi, M., Simonen, K., & Evins, R. (2025). What matters the most in designing low-carbon buildings in Canada? Exploring the tradeoff between embodied and operational carbon in early stage design. Energy and Buildings, 334, Article 115482. https://doi.org/10.1016/j.enbuild.2025.115482

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Abstract

Reducing global greenhouse gas emissions is a crucial sustainability objective around the world. The ambitious sustainability targets that have been defined for the building sector can only be achieved through carbon-sensitive design from the beginning. Multiple design parameters, their impacts on building performance, along with embodied and operational carbon tradeoffs makes it difficult for architects to compare design alternatives in the uncertain context of early-stage design. Tools and methods often focus more on either operating efficiency or material selection rather than assisting architects in making holistic carbon-sensitive design decisions.
In this research, a design-compatible methodology for low-carbon buildings was developed by using design exploration methods and parametric calculations of whole-life carbon emissions. The model was run for seven Canadian cities, resulting in over 20,000 design scenarios to capture a broad range of potential solutions. The study investigates the most influential design parameters in relation to the varying carbon intensity of local grid electricity. The results show that despite the significant impact of climate, local grid carbon emission intensity plays the most crucial role in defining building design priorities in order to optimize for total life carbon impacts. The results also indicate that mechanical and structural systems play a significant role in building carbon footprint. The results also show that in cities with high grid carbon factors, optimizing window-to-wall ratio, level of insulation and geometry can contribute the most to reducing carbon footprint. Conversely, in cities with low local grid carbon emission intensity, structural material and mechanical systems selection are highly impactful and all other factors play a marginal role.

Keywords

Life Cycle Assessment; Embodied Carbon; Operational Carbon; Building Carbon Footprint; Early-Stage LCA; Design parameters; Design Space Exploration; Sensitivity Analysis