A New Approach for Commercial Building Energy Performance
Addendum to code provides alternative compliance pathways for builders.
The first significant change in performance-based energy code compliance in 25 years will provide a single performance-based methodology for demonstrating both minimum code compliance and above-code performance. A pending change to ASHRAE Standard 90.1—Addendum bm—will create a new alternative path for meeting the minimum requirements for energy efficient designs for buildings (except for low-rise residential buildings) under construction or renovation.
Historically, meeting ASHRAE Standard 90.1 requirements involved two paths: (1) meeting mandatory prescriptive minimum requirements, and (2) meeting mandatory performance requirements for establishing a baseline energy cost budget based on building size and program. Under this practice, "above-code" projects were forced into duplicative energy modeling based on multiple requirements: one for demonstrating minimum code compliance, and another for demonstrating above-code performance.
Through funding from DOE's Buildings Technologies Office, Michael Rosenberg, a scientist in PNNL’s Electricity Infrastructure & Buildings division, spearheaded the effort to create and advance the new addendum, which combines a new vision for performance based codes with several previous and disparate attempts. He introduced the concept to the Standard 90.1 committee, led a working group tasked with refining the proposal, and took responsibility for responding to hundreds of pages of public comments.
Addendum bm, now in the final stages of the code development process, updates Appendix G to allow for both code compliance and above-code demonstration. The change establishes a fixed and independent baseline combined with a set performance target broken down by building type and climate zone, and expressed overall as a performance index ranging from 1.0 (baseline) to zero (net zero energy). The final product—approved with near unanimous consent—is the culmination of three year’s work, including three rounds of public review and refinement of the addendum to address stakeholder concerns.