We have a project that consists of 1 level of retail, 7 levels of above grade parking, 8 levels of commercial office space, and 16 levels of residential (apartment) space. Based on overall building square footage, the baseline energy model would utilize System 7 – VAV with Reheat. However, under normal circumstances, if the building was 100% residential the baseline would use System 1- PTAC. It could also be argued that because the office space is an 8am-5pm occupancy and the residential space is 24/7 that exception G3.1.1.b could be used to model each residential unit as an individual thermal zone with a packaged rooftop unit. How can we determine how the baseline should be set up? Any guidance would be appreciated. Thanks.