7/16/2024
Group 1: Creating a Streamlined BEM Process
Co-Chairs: Dimitri Contoyannis, Supriya Goel, and Neal Kruis
Working Group 1 kicked off the year with a January webinar focused on a comparison of compliance modeling approaches. Supriya Goel and Neal Kruis opened the session with highlights from the 2024 CalBEM Symposium. These covered updates on CalBEM-awarded projects, ACM software certification, a presentation on Building Performance Standards (BPS) from Duane Jonlin of the City of Seattle, and a discussion inspired by Amir Roth’s plenary talk on the BEM Standards landscape.
Greg Collins then presented findings from the CalBEM-funded project, “Streamlining Energy Compliance Modeling in California: Case Studies from BEM Practitioners.” The project compared Title 24’s ACM methodology with ASHRAE 90.1’s PRM approach, aiming to explore how aspects of PRM could improve modeling flexibility in California. Greg emphasized differences in rulesets, metrics, and operational assumptions, and highlighted that increased modeling flexibility could bring compliance model results more closely with actual building operation. A Q&A followed, with attendees offering insights on modeling inputs, performance curves, and the impact of varying compliance metrics; underscoring the complexity and opportunity in aligning design and compliance models.
If you missed these recent meetings, meeting notes and materials can be found in the CalBEM Collaborative Efforts SharePoint here.*
The Prototype Unification Technical Advisory Group led by Rahul Athalye (NORESCO) and Bryan Boyce (Energy Solutions) continues to make progress on advancing its goal to develop a single set of prototypes for use by all California state agencies and other public research/policy purposes. The TAG met in February and May 2025. The team’s recent focus has been developing nonresidential building prototypes including offices, while continuing to fine tune residential building prototypes. The team also unveiled a new webpage which shares recent updates and links to models and documentation.
To attend future Group 1 meetings, or simply to stay in the loop, sign up for the WG1 mailing list.
Group 2: Developing BEM Education and Resources
Co-Chairs: Nick Brown and Erik Kolderup
Working Group 2 started the year by exploring the benefit of defined knowledge, skills, and abilities (KSAs) for building energy modelers. In the January webinar, Erik Kolderup and Nick Brown led a discussion focused on a key problem identified at the 2024 Symposium: the lack of clarity around BEM practitioner roles, required skills, and educational pathways. Educators Jason Oliver and Kyle Konis contributed insights on the importance of communication skills, project-based learning, and clarifying expectations for new professionals entering the field.
The group reviewed existing resources and considered potential actions including the development of a KSA white paper, expanded content for the CalBEM resource hub, and alignment with existing BEM certifications. Although only modest support was expressed for pursuing a white paper, several attendees noted there is value in developing a career-stage-specific framework or graphic that outlines BEM career pathways and role distinctions.
If you missed these recent meetings, notes and slides can be found in the CalBEM Collaborative Efforts SharePoint here.*
The “Open Source Data Visualizations for BEM Quality Assurance” project led by Greg Collins kicked off in June 2025. The project aims to develop an open-source tool that analyzes energy model result file outputs to allow users to troubleshoot unexpected modeling results or optimize a model. The project has recruited volunteers from Working Groups who will provide input on the data visualization.
The “BEM Career Pathways Initiative” project led by Neil Bulger and Michael Sawford with A2 Efficiency was approved by the CalBEM Steering Committee in April 2025. This project is currently going through funding processes and expects to kick-off in Q3 2025. The project aims to engage with students via a lecture series that shares BEM career opportunities.
To attend future Group 2 meetings, or stay in the loop in real-time, sign up for the WG2 mailing list.
Group 3: Advancing BEM Capabilities and Metrics
Co-Chairs: Haile Bucaneg, Neil Bulger, and Michael Sawford.
Working Group 3’s January webinar reviewed top BEM issues identified at the CalBEM 2024 Symposium and focused on challenges in modeling complex HVAC systems. The Co-Chairs shared a recap of top issues from the 2024 Symposium, including gaps in heat pump performance data, modeling resources for existing buildings, performance trade-off limits, and barriers to integrating new technologies into compliance software.
Michael Sawford presented a proposed project to provide modeling guidance and example files for complex HVAC systems. The discussion emphasized the need for clear, officially supported methods, and highlighted challenges with unapproved workarounds. Attendees called for a living repository of modeling solutions, improved example files in software, and clearer alignment with CEC guidance. The group supported moving forward with a phased approach that starts with documenting existing workarounds and developing more example files for compliance software before tackling workaround solutions.
If you missed recent meetings, notes and slides can be found in the CalBEM Collaborative Efforts SharePoint here.*
The “Addressing Complex HVAC Systems in Code Compliance” project, led by Neil Bulger and Michael Sawford (A2 Efficiency), was approved by the Steering Committee in April 2025 and is currently going through funding approval processes. This project aims to fill the gap as outlined in January 2025 WG3 meeting by identifying complex HVAC modeling pain points and existing work arounds, and creating example model files for modeler reference.
To attend future Group 3 meetings, or stay in the loop in real-time, sign up for the WG3 mailing list.
Cross-Pollination Activities
In spring 2025, the CalBEM Co-Chairs led two cross-pollination meetings on topics that touched each Working Group: AI in BEM and BEM accuracy.
Spring Cross-Pollination Webinar: AI in (Cal)BEM (April 17, 2025)
CalBEM hosted a cross-pollination webinar focused on the emerging role of artificial intelligence in building energy modeling (BEM). Dr. Tianzhen Hong (LBNL) and Dr. Liang Zhang (University of Arizona) presented research on AI for BEM applications, including how it could be used for digesting results, simulation workflow automation, QA/QC, and benchmarking or calibration. Dr. Zhang presented on how to use large language models (LLMs) effectively for BEM applications and noted that agent-based workflows and retrieval augmented generation (RAG) offer potential for BEM automation and education, but that investment must be made to make these types of tools accurate and useful.
Discussion centered around opportunities and limitations of AI tools, such as generating geometry, streamlining HVAC modeling, and developing self-correcting models. Questions highlighted the need for structured model repositories, integration of AI with compliance rulesets, and the potential for AI to improve productivity in compliance and design modeling workflows. Attendees noted a desire in future meetings to highlight real-world case studies on AI tool applications to BEM practitioner workflows.
Spring Cross-Pollination Webinar: BEM Accuracy (May 7, 2025)
CalBEM’s second cross-pollination meeting examined the role of accuracy in building energy modeling, especially in the context of compliance and design. Presentations by Haile Bucaneg (CEC), Neil Bulger (A2 Efficiency), and Greg Collins (Zero Envy) explored distinctions between accuracy and precision, and discussed tensions between compliance modeling constraints and real-world building performance.
The group debated whether greater modeling accuracy supports better design outcomes or complicates compliance processes. Topics included flexibility in input assumptions, architecture accuracy, and mechanical engineering load accuracy. Participants noted a desire to improve accuracy in design models and to streamline the path to compliance.
The Co-Chairs opened an audience poll to learn more: when asked what the least accurate elements in a compliance model are, the top answers were occupant behavior and miscellaneous electric loads. When asked whether the inaccuracy of predicting actual energy use in compliance models is a problem that needs to be worked on, 60% said yes (30 responses). Participants left on the note that accuracy should be purposeful, context-specific, and balanced against time, resources, and modeling goals.
Find more poll results, meeting recordings, and notes here.*
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* Working Group participants can email info@calbem.org to gain access.