We are requesting a USGBC credit interpretation for LEED 2.1 Energy & Atmosphere Credit 1, Optimize Energy Performance. Our project is a County Juvenile Justice Facility located in California that includes 24-hour occupancies (detention / holding cells and other 24-hour support spaces) that are exempt from the local energy code (Title 24). The project also includes office and other support spaces that are required to comply with Title 24. For modeling of building occupancies that are not covered by Title 24, our local utility, PG&E, in developing the Savings By Design New Construction Energy Performance Incentive, funded a version of the California compliance software (EnergyPro) in 2002 that allows for DOE-2 energy performance modeling of both Title 24-compliant and Title 24-exempt occupancies for buildings. The version is EnergyPro 3.9 and, like its "parent" (EnergyPro version 3.14 that is used in Title 24 compliance), allows for modeling of a "standard" building against which the "proposed" building is compared. For our purposes, the "standard" model for the juvenile detention portion of the facility was developed consistent with "typical" county detention facilities in California, in terms of construction type, HVAC and lighting systems. For the Title 24 compliance occupancies of our project, the software is using Title 24 standard criteria; i.e., the software in all other aspects (assumptions, reports simulation engine etc) is identical. We are requesting confirmation that use of EnergyPro version 3.9 and use of the equivalency table (ASHRAE 90.1- Title 24) as per the USGBC\'s 10/25/2001 ruling, is acceptable for establishing the energy performance for EA Credit 1.
The Savings By Design approach is not allowed because there is insufficient information on the "standard" assumptions for the exempt occupancies. It is unknown as to whether or not the standard assumptions for the exempt occupancies meet ASHRAE 90.1-99 prescriptive requirements, and therefore estimated energy cost savings may be overpredicted. As noted in EAc1 CIR ruling dated 10/25/2001, there are two options for dealing with California Title 24 Energy Standards. The first option is based on Title 24 and the second option allows the project to be modeled according to the LEED Energy Modeling Protocol. If measures have been taken to make the areas that house exempt occupancies more efficient, it may be beneficial to the project to follow option 2 and use ASHRAE 90.1-99 for the entire project to demonstrate energy cost savings . Otherwise, the team may use option 1 with Title 24 and exclude exempt occupancies.