WBLCA Benchmark Study v2

The Lab is currently conducting a multi-year project to develop a robust and harmonized database of WBLCA benchmarks.


In 2017, the CLF published the Embodied Carbon Benchmark Study for North American buildings. Since then, the practice of whole-building life cycle assessment (WBLCA) has grown rapidly in the AEC industry, and it has become clear that more robust and reliable benchmarks are critical for advancing work in this field. The new CLF WBLCA Benchmark Study (Version 2) will build upon research and insights from the 2017 study. The project will expand our research methodology and result in geographically and typologically specific benchmarks for buildings, systems, and assemblies modeled with consistent scope and background data. This will allow designers and decision-makers to set reliable embodied carbon targets and understand the potential for reduction throughout the design and construction processes.

Problem Statement

Currently, it is difficult to set robust targets or benchmarks for the embodied carbon of building projects due to the lack of a robust collection of WBLCA models. Existing studies have been based on a very small number of calibrated models, or large low-quality and non-harmonized datasets, making it difficult to understand whether variability in carbon emissions stems from modeling practice, background LCI data, or actual design decisions. Over the last 5 years, there has been rapid adoption of WBLCA by architecture and engineering firms during design and construction. However, there is currently no centralized repository of WBLCA models from which to conduct research or evaluate trends.

This project will fill a critical gap in the AEC industry and help enable architects, engineers, policy makers, and the entire design community to work towards realistic and measurable embodied carbon reductions at the building scale.

Project Phases

There are 3 components to this project that build on each other to ultimately deliver a more robust dataset, analysis framework, and set of benchmarks:

  1. Pilot Phase (Fall/Winter 2022) The pilot phase of the study aims to test data collection and analysis processes that will be used for future phases, establish pilot partners and a pilot dataset of projects, and built internal capacity to advance the remainder of the project. The pilot phase will be critical for establishing the infrastructure for future phases.
  2. California Total Carbon Report (2023) This project will focus on the full carbon impacts of buildings in California, including both operational and embodied carbon emissions. The dataset will be compiled from a discrete set of real-world projects and will be used to produce a case study report examining the relationship between embodied and operational carbon over time when taking into account future grid decarbonization projections. The California Total Carbon Report will provide designers, policymakers, and other AEC stakeholders with timely data and analysis on the relative carbon impacts of new buildings constructed in California to inform policy.
  3. Initial North American Benchmarks and Public Database (2023-2024) This project will culminate in a final report on embodied carbon benchmark figures that can be used to improve current estimates of typical, low, and high embodied carbon values for buildings in North America.  It will also include the publications of a high-quality, harmonized dataset of WBLCA models, associated LCA model results, and material quantity estimates. This project will include extensive stakeholder engagement with industry representatives and data-sharing partners to develop frameworks and methodologies for data collection, analysis, and technical review. The team will work to collect project and LCA data for 200+ real-world buildings, perform rigorous statistical analysis on the dataset, and undergo multiple rounds of technical review.  Anticipated publications include:
  • WBLCA modeling and reporting guidance for the database
  • Findings from our background research and literature reviews
  • Year one data findings with preliminary baseline figures
  • Open-access buildings database published on GitHub.
  • Peer-reviewed paper on data collection methods and benchmark development

Research Questions

  • What is a reasonable WBLCA benchmark for new construction projects?
  • What is the expected EC per building element (e.g., structure, envelope, interiors, site) and per building characteristics (e.g., building use, construction type, height, location)?
  • What is the expected variability associated with modeling practice (e.g., tool type, background data, calculation methodology, model resolution)?
  • What design decisions support the most significant embodied carbon reductions?

Goals and Objectives

The ultimate goals of the WBLCA Benchmarking Study across all phases are to:

  • Enable building owners, designers, and policy-makers to use the database to compare the environmental impacts of buildings with a relevant benchmark figure
  • Enable building certification schemes to set building benchmarks/targets based on current data and evaluate projects using consistent methods.
  • Encourage additional research and analysis: Researchers can use the resultant database to analyze and track the environmental impacts of a large number of buildings. This can lead to a better understanding of trends in material use, carbon intensities, building efficiency, best practices, and pathways to decarbonization.
  • Designers and researchers will be able to better understand modeling practices that improve the accuracy and comparability of WBLCA model results.
  • Policymakers can use the database to test scenarios and set performance targets to help motivate EC reductions at a city, state, or federal level.
  • Improve the state of practice with robust, standardized, and widely-implemented methodologies for embodied carbon modeling and reporting, and be able to contribute to harmonization efforts among existing reporting frameworks.

Open Call for Participants

The CLF is actively seeking collaborators to help support this project. If you are interested in participating in the study or simply want to stay up to date on its progress, please fill out this General Questionnaire. The questionnaire asks for basic information about your organization, your level of interest, and your capabilities for participating in the study. Responses from the questionnaire are confidential and will be used internally by the CLF to help inform the scope and structure of the project.

For general inquiries about the project please email [email protected].

Project Updates

Greenbuild 2023 UpdateSeptember 28th, 2023

We recently had the pleasure of presenting a project update alongside Lindsey Kahler of SERA Architects and Brie McCarthy of Miller Hull at this year’s Greenbuild 2023. Our session was titled Embodied Carbon Benchmarking: the prerequisite to making meaningful impact reductions within the AEC industry, and we explored the importance of embodied carbon benchmarking and the ways in which design practitioners are engaging in similar efforts at the firm-scale. As promised to our Greenbuild audience, our slides can be downloaded here.

Open Call for Data Contributors—May 22nd, 2023

We are excited to announce the official launch of our open call for data contributors! Our goal is to collect at least 200 WBLCAs of real-world projects so that we can analyze the environmental impacts of buildings and provide critically needed benchmark data to designers, policymakers, and other organizations working to reduce embodied carbon. To do this will require the help of our amazing CLF network and other practitioners out in the real world conducting WBLCAs. With enough data contributors, we may be able to far exceed our goal of collecting 200 projects and build an even more robust dataset.

For those of you who are interested (or may be interested) in submitting data to this study, please fill out this brief Data Collection Expression of Interest form so that we can add you to future meetings and workshops regarding our data collection process. If you know of others who might be interested, we would greatly appreciate your help in spreading the word. The data collection expression of interest is a targeted survey for WBLCA practitioners to help us identify interested parties and move toward collecting real project data. For non-practitioners, please be aware that there will be other opportunities to stay engaged and contribute to this project that we will continue to share in the future.

Data Collection Introduction call—May 3rd, 2023

We recently completed an informational call on the data collection methods and processes that will be used for the WBLCA Benchmark Study v2. This recording introduces the types of data that we will be seeking as well as what the process will look like for participants who are interested in contributing data to this study. It includes examples of project requirements, modeling requirements, data fields that will be collected, and brief overviews of guidance documents that will be provided. We will soon be launching surveys for practitioners to express their interest in contributing data and indicate the types and quantities of projects that may be available. Additionally, the survey will include opportunities for a wide range of practitioners to provide feedback on current WBLCA modeling practices that will help to further inform our data collection efforts.

We are gearing up to officially launch our call for data soon. Please stay tuned for more updates!

Official Launch of Phases 2-3March 27th, 2023

The CLF is pleased to announce the launch of the next two phases of the CLF Benchmark Study V2. This year we will be developing the “California Total Carbon Report” (phase 2) which will focus on the whole-life carbon impacts of buildings in California, including both operational and embodied carbon emissions. Concurrently, the CLF will be gathering data and conducting stakeholder engagement to support our larger “North American Benchmark and Public Database” (phase 3) which will continue through 2024 and lead to updated embodied carbon benchmarks for North America.

We’ve recorded a full project overview that describes the entire project and each individual effort in more detail. This 15-minute recording also outlines the ways we will be conducting stakeholder engagement in the coming weeks and future project efforts to be aware of.

As always, if you are looking to provide data for this study or participate in other ways, we invite you to fill out our General Questionnaire to join the project email list and receive important project updates.

Pilot Phase CompletionOctober 2022

The project team has recently wrapped up our initial pilot phase of the WBLCA Benchmark Study which focused on reviewing existing literature and building internal data infrastructure. During the pilot phase, we:

  • Developed a process for architecture or engineering firms to easily submit detailed Tally models, Bill of Materials, and other project information
  • Developed infrastructure to enable robust data analysis at a building, assembly, and material scale
  • Conducted extensive background research on WBLCA benchmarking and benchmark development in the US and Europe
  • Tested data collection templates and reporting processes
  • Identified stakeholders and interested parties for future participation

In the next phases of the project we will expand the project to:

  • Include a larger sample set of firms, projects, and WBLCA tools
  • Build upon the work completed in the Pilot Phase
  • Establish stakeholder working groups for technical advisory, communications, harmonization, and more

The CLF is actively seeking collaborators from both practice and academia to ensure that the data gathered for the study is sound, that the results are properly analyzed, and that the findings are communicated in ways that best support the AEC community in effectively driving decision-making and decarbonization in the built environment.

CLF WBLCA Benchmark Project Logo

Research Projects

Tools for Measuring Embodied Carbon

This list provides a quick overview of available tools for architects, engineers, and consultants to evaluate the environmental impacts of buildings and building materials using life cycle assessment.  This is a non-exhaustive list that does not include many tools...

Learn More

Material Baselines for North  America / August 2023

The North American Material Baselines Report provides: A snapshot of the state of Environmental Product Declarations (EPDs) for North American-produced building materials, including: Background and methodology CLF Baselines Appendices About The CLF Baseline values...

Learn More

POD|LCA: Parametric Open Data for Life Cycle Assessment

About In the spring of 2022, ARPA-E announced a cohort of material and building design teams for the “Harnessing Emissions into Structures Taking Inputs from the Atmosphere” (HESTIA) Program.  Each team in the program is working on a project to develop a...

Learn More