If I model a building where there is mechanical ventilation, how shall I consider the infiltration (i.e. "uncontrolled inward air leakage to conditioned spaces through unintentional openings in ceilings, floors, and walls from unconditioned spaces or the outdoors", see ASHRAE 62.1-2007)? Suppose that no blower door test was made.
Generally I model a constant value of ACH, which I determine according to my experience, but shall I respect any particular document (e.g. an ASHRAE standard)?
With Regards