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855773644-LEED-v5-BD-C-Reference-Guide-Launch-Edition - Page 232

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  • The project complies with ASHRAE 90.1-2019, Addendum cr G1.2.1(c) requirements or ASHRAE 90.1-2022 Section G1.2.1(d) requirements.

    • The project complies with Thermal Energy Demand Intensity (TEDI) criteria specified in the referenced code requirements.

    • The envelope weighted average UA (U-factor x Area) in all climate zones and the weighted average Solar Heat Gain Coefficient (SHGC) in climate zones 1 through 4 does not exceed the prescriptive maximum by an established percentage. Replace fenestration area exceeding the prescriptive maximum with opaque assemblies to determine the prescriptive maximum UA.

    • The energy consumption model for the proposed design with a proposed envelope does not exceed the simulated energy consumption for the proposed design with a prescriptively compliant envelope by a given percentage.

The 2021 International Energy Conservation Code (IECC 2021) and ASHRAE 90.1-2019 with Addendum cr are equivalent.

The 2024 International Energy Conservation Code (IECC 2024) with additional envelope backstop provisions and ASHRAE 90.1-2022 are equivalent.

For both versions of the standard:

- _IECC, Section C407, Total Building Performance_ may only be used to document

prerequisite compliance with additional documentation demonstrating compliance with the envelope backstop.

- Use _IECC Prescriptive Compliance_ ( _C402_ through _C406_ ) instead of the _ASHRAE_

90.1-2019 prescriptive method.

District Energy Systems (DES)

ASHRAE 90.1 refers to district energy systems (DES) as purchased chilled water or purchased heat, even when this energy is part of a campus distribution plant, and not directly purchased from a utility or municipality. Because DES systems are outside the project scope of work, DES efficiency cannot contribute towards achieving prerequisite compliance.

For projects that use the ECB method, model purchased heat and/or purchased chilled water as independent energy sources using the same utility rates per unit of energy for the energy cost budget and design energy cost models.

U.S. Green Building Council LEED v5 Reference Guide for Building Design and Construction, April 2025 Launch Edition 222

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