In multifamily buildings, particularly in the Northeast, exhaust ventilation strategies are the norm as a means of meeting both local exhaust and whole-unit mechanical ventilation rates. The issue of where the fresh air is coming from is gaining significance as air-tightness standards for enclosures become more stringent, and the normal leakage paths through the building envelope disappear. This research effort by the Building America team, Consortium for Advanced Residential Buildings, evaluated four different strategies for provide make-up air to multifamily residential buildings, which included several weeks of building pressure monitoring.