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Previous posts have questioned the ability of VAV or OnOff fans to cycle the HVAC system. It is not the fan that varies the air flow, but the parent, or the system that houses the coils and fan. Terminal boxes control air flow for VAV systems.

• Air loops are compatible with Fan:OnOff, to the extent that the parent object controls operation via the fan operating mode schedule (and the parent must allow Fan:OnOff)
• Air loop equipment can also be modeled as zone equipment given the correct parent object choice (e.g., Furnace as air loop or PTAC as zone equipment). The results should be similar if no outdoor air is specified.

Modeling attic vs conditioned space could be accomplished using a duct loss/leakage model. AirflowNetwork has this ability.