The American Society of Heating, Refrigerating and Air-Conditioning Engineers opened public review on October 16, 2026, on a draft addendum that would turn its loosely optional building decarbonization assessment into a structured, two-level procedure and create a new credentialed role to carry it out. The proposal, Addendum d to ANSI/ASHRAE/ACCA Standard 211-2018 (RA 2023), Standard for Commercial Building Energy Audits, is the first concrete piece of a restructuring ASHRAE announced in July: splitting its flagship energy standard, ANSI/ASHRAE/IES Standard 90.1, Energy Standard for Buildings Except Low-Rise Residential Buildings, so that operational carbon reduction eventually lives in its own document instead of inside the energy efficiency rulebook that has governed commercial building design for more than 50 years. Comments on the draft are due November 15, 2026.

A standard built for one job, now dividing into two

ASHRAE’s announcement, dated July 16, 2026, said Standard 90.1 will keep its original focus: energy efficiency requirements justified by energy cost, nothing broader. The carbon-specific provisions added as Addenda M and N in the 2025 edition will instead move into a new, separate, optional companion publication covering operational greenhouse gas emissions. The work falls under the 90.1 Standing Standard Project Committee’s six-year plan, which spans the 2028 and 2031 revision cycles, and the committee itself counts 153 members and consultants. ASHRAE President Sarah Maston framed the split as reinforcing, not diluting, the standard’s role, saying Standard 90.1 “has helped define energy-efficient commercial building design for more than 50 years” and that a dedicated pathway for emissions reduction lets the organization respond to market demand without losing that core. Trade coverage of the announcement pointed to local measures such as New York City’s Local Law 97, the 2019 provision that caps carbon emissions from large buildings citywide, as the kind of policy driving jurisdictions to ask ASHRAE for emissions guidance distinct from pure energy-efficiency requirements. ASHRAE has not set a publication date for the standalone document and has not said whether it will be issued as a standard or a guideline.

Standard 211 becomes the test case

Addendum d is where that split gets its first real content. Standard 211 already carries an optional, informative Appendix H, Building Decarbonization Assessment, added in 2023, which lets an auditor voluntarily report Scope 1 and Scope 2 greenhouse gas emissions alongside a conventional energy audit and note options for cutting onsite emissions, reducing refrigerant leakage, and adding onsite renewables. The draft now open for advisory public review would move that work into normative Section 5, formalize it as Level 1 and Level 2 Decarbonization Assessment procedures parallel to the standard’s existing Level 1, Level 2, and Level 3 energy audit tiers, clarify exactly how an energy audit and a decarbonization assessment relate to each other, and, notably, define a new role: the Qualified Decarbonization Assessor, with its own listed responsibilities. ASHRAE’s October 16 standards actions notice describes this as a first advisory public review, meaning the committee is testing direction and language before committing to a binding draft. The comment window runs 30 days, closing November 15, 2026.

A credential question the draft does not fully answer

The Qualified Decarbonization Assessor designation arrives alongside, but separately from, the Certified Decarbonization Professional credential ASHRAE launched in 2024, which the organization has called its most applied-for certification and which tests competency across decarbonization drivers, project planning, construction and renovation, efficiency measures, facility management, and distributed energy resources. The two are not the same thing. The CDP is a personal certification earned through an exam. The QDA, as drafted, is a role defined inside Standard 211 itself, specifying who is qualified to perform or sign off on a Level 1 or Level 2 decarbonization assessment under the standard. ASHRAE has not yet said in the public materials whether holding a CDP will automatically satisfy the QDA qualification or whether the two will require separate recognition, a gap that energy auditors and mechanical engineers reviewing the draft will likely raise during comment. Equally notable is what the addendum does not touch. ASHRAE’s own fact sheet for Standards 180 and 211 describes the existing Appendix H content strictly in terms of Scope 1 and Scope 2 operational emissions, with no mention of embodied carbon. Nothing in the draft extends Standard 211 into the materials side of decarbonization, the life-cycle data that Environmental Product Declarations exist to supply. For a committee working in parallel with ASHRAE’s broader 90.1 split, which is also confined to operational carbon, that leaves the embodied-carbon half of any building’s footprint outside this standard’s reach for now.

Why code officials and specifiers should care now, not later

Standard 90.1 editions are not academic documents. States write specific editions directly into building code dockets, and the edition named determines what a project must meet. West Virginia’s State Fire Commission illustrated the point in July, finalizing changes to the state building code, 87 CSR 4, effective July 29, 2026, that paired the 2024 International Energy Conservation Code for residential construction with ANSI/ASHRAE/IESNA Standard 90.1-2019 for commercial buildings. The Northeast Energy Efficiency Partnerships had urged the state to specify Standard 90.1-2025 or, at minimum, 90.1-2022, arguing the 2019 edition was already two cycles behind current practice. West Virginia kept 2019 anyway. When a jurisdiction locks in an edition number, it also locks in whatever carbon content sits inside or outside that edition at the time, which is exactly why the content ASHRAE chooses to keep in or move out of Standard 90.1 going forward will matter well beyond ASHRAE’s own membership. ASHRAE’s decision to move carbon provisions out of 90.1’s core, and to test a credentialed decarbonization-assessor pathway through Standard 211 instead, changes what future code dockets will actually be adopting when they cite ASHRAE by number. One mechanical engineer who reviewed the restructuring, Tarang Patel of TRV Mechanical Contractors, called the split a cleaner compliance path, arguing it lets jurisdictions adopt the tools that fit their own goals while keeping Standard 90.1 enforceable because it stays cost-justified. Trade coverage also noted that not every reviewer is convinced the split resolves every open question.

What to watch

Energy auditors, mechanical engineers, code officials, and manufacturers with a stake in how the Qualified Decarbonization Assessor role gets defined have until November 15, 2026, to file comments on Addendum d through ASHRAE’s online standards review system, and this is the stage at which the credential’s scope and its relationship to the CDP certification are still open to change. Separately, watch for ASHRAE to name and scope the standalone operational-carbon companion to Standard 90.1, work that continues through the committee’s 2028 and 2031 cycles with no publication date yet set. State code dockets are the third thing worth tracking: West Virginia’s choice shows states can and do lag several editions behind, and every docket still weighing a 90.1 edition will decide whether that jurisdiction’s commercial buildings end up under the old combined structure or the new split one. None of this reaches embodied carbon or EPDs directly, and that gap is itself worth watching, since it means the materials side of the decarbonization story still has no ASHRAE standard assigned to it.