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Appendix G, which directly compares the performance of the proposed design to that of a baseline building matching the prescriptive requirements. A BPF of 1.0 is used for all projects. Systems and equipment excluded from the scope of retrofit are modeled identically in the baseline and proposed models.

Appendix G PRM, alternative metrics in lieu of energy cost Although the ASHRAE 90.1, Appendix G PRM references a cost metric, the energy modeler may instead demonstrate EAp2: Minimum Energy compliance for the PRM using the future source energy metric referenced in EAc2: Enhanced Energy Efficiency, or a site energy metric, or a current source energy metric. Substitute all PRM references to “cost” with the new metric. BPFs used to assess compliance must be specific to the metric and the referenced version of ASHRAE Standard 90.1 .

EAc2: Enhanced Energy Efficiency only uses the future source energy metric and does not allow the use of the energy cost, site energy, or source energy metrics (See EAc2: Enhanced Energy Efficiency, Option 2 ).

Energy modelers can limit documentation level of effort by calculating both prerequisite and credit compliance using the future source energy metric.

For initial buildout and substantial alterations, adjust the BPFs to align with the selected metric. For other alterations, the BPF is always 1.

OPTION 1. ASHRAE 90.1-2019, APPENDIX G PRM. ALTERNATIVE METRICS

• Future source energy . Calculate the PIT for both the prerequisite and EAc2: Enhanced Energy Efficiency with BPFs from the prerequisite Table 1. 90.1-2019 equivalent BPFs for a future source energy metric.

• Site energy or source energy metric . (prerequisite only) Apply ASHRAE 90.1-2019, Addendum ch . For a source energy metric, match those listed in Addendum ch Table X4-1 and follow Addendum ch Section X5 Methodology for BPF Adjustment to Account for Localized Conversion Factors.

OPTION 2. ASHRAE 90.1-2022, APPENDIX G PRM. ALTERNATIVE METRICS

Future source energy metric - Calculate the PIT for the prerequisite with BPFs from the prerequisite. See Table 2, ASHRAE 90.1-2022 — Equivalent BPFs for a future source energy metric.

Calculate the less stringent PIT for EAc2: Enhanced Energy Efficiency using Table 6. 90.1-2019 equivalent BPFs for a future source energy metric.

U.S. Green Building Council LEED v5 Reference Guide for Interior Design and Construction, April 2025 Launch Edition 110