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Extracted Content
Summary of ASHRAE 90.1 Section 4.2.1 Compliance Paths
Projects must choose from one of the following compliance paths from ASHRAE 90.1, Section 4.2.1:
- Prescriptive Method
o ASHRAE 90.1-2019, Section 5–10 (for projects applying Option 1)
o ASHRAE 90.1-2022, Section 5–11 (for projects applying Option 2)
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Energy Cost Budget Method (ECB)
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Appendix G, Performance Rating Method (PRM)
ASHRAE 90.1 further distinguishes these three compliance paths for each type of construction:
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Section 4.2.1.1: New Buildings
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Section 4.2.1.2: Addition to Existing Buildings
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Section 4.2.1.3: Alterations of Existing Buildings (applicable to major renovations)
The path commonly referred to as the prescriptive method requires individual compliance with each referenced 90.1 section (building envelope, HVAC, service water heating, electrical power, lighting, other equipment, and in ASHRAE 90.1-202, additional efficiency requirements).
The Energy Cost Budget Method (ECB) and Appendix G, Performance Rating Method (PRM) offer greater flexibility in trading off performance between different systems. These methods rely on whole-building energy modeling, demonstrating that the proposed building performs at least as well as a project meeting the prescriptive requirements. For both methods, the building envelope backstop additionally constrains building envelope performance.
To pursue additional credit for regulated energy efficiency in EAc3: Enhanced Energy Efficiency, project teams must apply either the prescriptive method or the Appendix G, Performance Rating Method.
Key Changes in ASHRAE 90.1-2022
The following table briefly summarizes key changes to the ASHRAE Standard between the 90.1-2019 and 2022 publications. For a more comprehensive summary, refer to ASHRAE 90.1- 2022 Foreword and ASHRAE 90.1-2022, Informative Appendix M Addenda Description.
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