855773644-LEED-v5-BD-C-Reference-Guide-Launch-Edition - Page 225

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Additional Considerations EAc3: Enhanced Energy Efficiency, Option 1. Prescriptive Method, Path 1

CASE 1. ASHRAE 90.1-2019 Projects that comply with Option 1 of the prerequisite using the ASHRAE 90.1-2019 prescriptive method may earn points for additional improvements to regulated systems by documenting achievement of energy credits using the methodology referenced in ASHRAE 90.1-2022, Section 11. Additional Efficiency Requirements .

CASE 2. ASHRAE 90.1-2022 Projects that comply with Option 2 of the prerequisite using the ASHRAE 90.1-2022 prescriptive method are awarded four points under the New Construction rating system, or two points under the Core and Shell rating system.

Additional points may be awarded for incremental energy efficiency credits beyond the minimum required by ASHRAE 90.1-2022, Section 11. Additional Efficiency Requirements.

PERMISSIBLE TRADE-OFFS FOR PRESCRIPTIVE METHOD

Some sections provide an option for limited trade-offs within the section:

• Section 5.6 Building Envelope Trade-off Compliance Path assesses the overall envelope performance compared to a prescriptively compliant envelope, permitting trade-offs between building envelope components. For example, improved wall assembly U-factors may compensate for window-to-wall ratios that exceed the 40% prescriptive maximum. The project complies when the proposed envelope performance factor does not exceed the base envelope performance factor determined following the simplified modeling protocol in ASHRAE 90.1, Normative Appendix C. Software, such as the freely available COMcheck tool, automates this Appendix C energy simulation, building envelope data entry by the architect or design professional and completing these calculations in a matter of minutes.

• Section 6.6.2 Mechanical System Performance Path ( 90.1-2022 only) uses simplified energy modeling to calculate the Total System Performance Ratio (TSPR) for the project’s HVAC systems, typically used for office, retail, hotel/motel, multifamily/dormitory, and school or education buildings. Professional mechanical engineers without building energy modeling experience can calculate the TSPR using a software tool that automates the analysis.

U.S. Green Building Council LEED v5 Reference Guide for Building Design and Construction, April 2025 Launch Edition 215