When modelling for SBEM it is important that all users follow the official guidance. The iSBEM user guide contains specific guidance on modelling roofs, unconditioned plant rooms and indirectly heated spaces such as corridors and stores.
The guidance also states that Unheated roof spaces & voids should not be modelled.
VE-SBEM users should only use the room type “Heated or Occupied” or “Other buffer space”. They should ignore all other options. If a space is indirectly conditioned then the user should set the space to be Heated or Occupied and then assign the system that is serving the adjacent space. If a space is unconditioned and totally enclosed then it should be defined as “Zones without HVAC”. To do this with the VE, set the room type to Heated or Occupied and then set the Main System to None. Smaller spaces such as cupboards and stores should be absorbed into the adjacent conditioned space.