Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
Yes, that is what the Measure is assuming. That when the system is on, the infiltration (Idesign in the ZoneInfiltration object) is reduced to 0.25 of the full value because it's assumed that when the system is on, the building is pressurized. When the system is off, it is assumed that infiltration can move freely into the building.
I will say that our research has shown that this isn't necessarily the case. We (the National Institute of Standards and Technology) have released a Measure called "Adding infiltration correlated for weather and building characteristics" which will take into account weather (wind and outside temperature), physical characteristics of the building, and system operation when calculating infiltration.
