TL;DR:
- ASHRAE announced a strategic direction for ANSI/ASHRAE/IES Standard 90.1 to remain the baseline energy efficiency standard for commercial buildings while introducing a separate framework to address operational emissions. The work plan targets 2028 and 2031 editions, with a move of Addenda M and N into a standalone publication focused on operational carbon reductions. This change signals a shift toward integrating life cycle and operational performance considerations without disrupting the core energy efficiency requirements today. For engineers, the update means continuing to design to 90.1-2025 as the baseline, while staying aware of an upcoming optional framework that jurisdictions may adopt to pursue deeper decarbonization goals. DOE federal-building rules and implementation timelines may influence project planning as compliance dates shift, including a stay on certain energy-efficiency requirements through September 1, 2026. Exam candidates should track the core 90.1 provisions while monitoring the new operational emissions pathway as it moves through public review and publication.
What changed
In a July 16, 2026 press release, ASHRAE outlined a formal direction to evolve ANSI/ASHRAE/IES Standard 90.1, Energy Standard for Buildings Except Low-Rise Residential Buildings. The core objective remains the energy efficiency baseline for commercial buildings, but a new, aligned document will address operational carbon reductions separately. The plan calls for a six-year work cycle with target documents in 2028 and 2031, emphasizing that 90.1 will still anchor design requirements while an optional framework will guide operational emissions reductions and allow jurisdictions to adopt specific decarbonization pathways. Addenda M and N, introduced in the 2025 edition, are planned to be transitioned from the core standard into this new standalone publication. This strategy aims to preserve the proven energy efficiency framework while providing a clear, adaptable route for future carbon reduction goals. (ashrae.org)
The 90.1 framework will continue to serve as the backbone for commercial building energy performance, with the new companion publication intended to address carbon reduction targets beyond site energy performance, including opportunities to account for renewable energy availability. The changes were presented as a response to market demand for clearer pathways to operational emissions reductions and to keep pace with evolving regulatory and client expectations. (ashrae.org)
Why this matters to practicing engineers
Design baseline remains stable today: For projects in 2026 and beyond, the baseline remains ANSI/ASHRAE/IES Standard 90.1-2025 for commercial building energy efficiency. This ensures that energy modeling, envelope design, lighting, and HVAC strategies continue to be governed by a well-established framework. Jurisdictions often reference 90.1 in tandem with IECC or local codes, so continuity in the baseline helps reduce project risk during code adoption cycles. (webstore.ansi.org)
Operational emissions as a separate pathway: The new companion publication will host a framework focused on operational emissions reductions, moving Addenda M and N into a standalone document. This approach allows jurisdictions and owners to pursue deeper decarbonization without altering the long-standing energy efficiency requirements that underpin 90.1 today. Practitioners should anticipate future modeling and documentation tasks related to operational carbon, including potential new metrics and reporting pathways. (ashrae.org)
Regulatory and market alignment: Regulators and large owners have shown sustained interest in decarbonization strategies that extend beyond traditional site energy metrics. The new pathway is designed to be adoptable through regulatory processes and may influence procurement and performance contracting practices as ownership groups seek to align with broader sustainability goals. The framework aims to complement, not replace, the established energy efficiency approach that has driven codes and standards for decades. (ashrae.org)
Public review and ongoing updates: The industry is already seeing active public review work on related addenda, illustrating that standards development remains dynamic. For example, the Illuminating Engineering Society notes public review activity for addenda to 90.1-2025, signaling ongoing refinement and opportunities to shape the next iterations. Engineers should participate in reviews when possible and track official publications to ensure compliance and design decisions stay current. (ies.org)
Practical implications for projects and exams
Project planning and design decisions: Until the standalone operational emissions framework is published, engineers can rely on 90.1-2025 as the baseline for site energy performance. Designers should prepare for potential future alignment with the new framework by documenting assumptions related to on-site energy generation, demand management, and operational carbon strategies as additive considerations rather than core requirements. This approach helps manage risk if a jurisdiction elects to adopt the operational emissions pathway later. (webstore.ansi.org)
Modeling and verification: The move toward an operational emissions framework implies potential new metrics, measurement, and verification approaches. Teams should start conversations about how to collect data on operational performance, how to model emissions beyond site energy, and how to align with future compliance pathways without compromising current energy efficiency goals. Stakeholders may increasingly request data on energy use intensity, carbon intensity of energy sources, and facility-level decarbonization plans as part of project deliverables. (ashrae.org)
DOE regulatory context: Federal buildings face energy efficiency standards with periodically updated requirements and related stay dates. As of mid-2026, the Department of Energy notes that certain federal compliance dates were stayed through September 1, 2026, creating a transitional window for agencies and project teams to align with evolving standards while federal rules catch up with industry practice. This regulatory context intersects with 90.1 adoption timelines and can influence procurement, design decisions, and project schedules for federal sites and those targeting federal funding incentives. (energy.gov)
Exam preparation considerations: For PE exam candidates in 2026 and beyond, the core focus remains on Standard 90.1 as the baseline reference for commercial building energy efficiency. Awareness of the upcoming operational emissions framework and its publication timeline is valuable, particularly for future exam content related to decarbonization strategies and integrated energy performance concepts. It is prudent to follow official ASHRAE and IES public review actions and to review the current 90.1-2025 edition plus addenda that may influence exam problems related to energy codes and building performance. (webstore.ansi.org)
Implementation timeline and next steps
2026–2028: ASHRAE SSPC 90.1 advances the six-year work plan toward 2028 and 2031 revisions, with the core emphasis on energy efficiency and cost-justified requirements. The new operational emissions pathway is developed in parallel, with a dedicated publication to host the framework for decarbonization beyond traditional energy metrics. (ashrae.org)
2026–2027: Addenda to 90.1-2025 continue to undergo public review, including addenda focusing on related topics that may transition into the standalone operational emissions document. Participation in public reviews can help practitioners anticipate future requirements and refine design practices accordingly. (ies.org)
2028–2031: Publication of the standalone operational emissions framework and its adoption by regulators and industry groups is anticipated as part of the long-range plan. The industry should monitor code development activity and prepare for possible crosswalks between site-energy based requirements and operational emissions criteria once published. (ashrae.org)
Sources
- ASHRAE, “ASHRAE Strengthens Standard 90.1 Foundation with Renewed Emphasis on Commercial Building Energy Efficiency,” July 16, 2026. (ashrae.org)
- Illuminating Engineering Society, “Standards Actions,” July 3, 2026, public review of ANSI/ASHRAE/IES 90.1-2025 addenda. (ies.org)
- Department of Energy, “Federal Building Energy Efficiency Rules and Requirements,” updated 2026, including stay dates through September 1, 2026. (energy.gov)
- ANSI/ASHRAE/IES Standard 90.1-2025, overview and status. (webstore.ansi.org)