We are working on a project pursuing LEED v4.1 certification using the Appendix G Performance Path. The air-cooled chiller in our design complies with the IPLV (Integrated Part Load Value) requirements but does not meet the full-load (FL) efficiency as specified by the minimum efficiency requirements of ASHRAE 90.1-2016.
The LEED v4.1 Guide states:
"If the HVAC efficiency does not meet the mandatory provisions, model the proposed efficiency as designed, and model the Baseline consistent with Appendix G."
Given this guidance:
- Does the chiller’s compliance with IPLV (but not FL) satisfy the intent of LEED and Appendix G modeling requirements?
- Are there potential risks to certification if the chiller does not meet the mandatory FL efficiency provision, even though the project complies with IPLV?
Tyler Thumma
7GroupLEEDuser Expert
67 thumbs up
February 21, 2025 - 11:08 am
The LEED v4.1 Guide and Appendix G allow for the Proposed model to be penalized for the lower efficiencies, and therefore the certification should not be at risk as long as other offsetting efficiency measures produce sufficient savings to meet the minimum thresholds. However, keep in mind that there are Path A and Path B efficiency requirements, so the Proposed chiller may comply with one Path but not the other. The Baseline chiller efficiency should be based on Path A.
Anurag Ghosh
Assistant Sustainability ManagerL&T Construction
1 thumbs up
February 22, 2025 - 9:18 am
Hi Tyler, I just had one doubt with respect to ASHRAE 90.1 2016 PRM.
Is the penalty applicable for not meeting the mandatory provisions in various sections like meeting specific lighting power densities with controls when using PRM?
Tyler Thumma
7GroupLEEDuser Expert
67 thumbs up
February 24, 2025 - 7:55 am
Yes the penalty would also be applicable to lighting power densities and controls.