"DES Energy Cost" Thread Follow-Up

The DES has always been optional because it was not included in the credit language until v4. You could always use 90.1 Appendix G addenda. There might be an interpretation on this but I would have to go dig for it. In lieu of following DESv2, the project team may choose to follow ASHRAE 90.1 2007 Appendix G modeling protocols, with or without ASHRAE 90.1 2007 addendums, e.g., addendum ai. If following ASHRAE 90.1 2007 district energy modeling protocols, without addenda, the heating source must be included in the energy models as purchased steam using identical energy rates in the baseline and proposed case energy models as indicated in ASHRAE 90.1 2007 Section G3.1.1.1, and the cooling energy must be modeled using purchased energy rates in the proposed case and the appropriate Appendix G baseline cooling system in the baseline case. If applying ASHRAE 90.1 2007 addendum ai, refer to ASHRAE 90.1 2007 addendum ai, Sections G3.1.1.1.1 through G3.1.3.10, for heating and cooling energy requirements. Any ASHRAE 90.1 2007 addenda implemented must be applied in whole and consistently among all LEED credits and prerequisites and the submittal documentation must clearly indicate any addenda that have been applied to the project documentation.