This study focused on the in-situ impacts of various whole-building dilution ventilation systems relating to differing sources of outside air and the spatial distribution of ventilation air. The project involved perfluorocarbon tracer gas (PFT) testing at two unoccupied, single-family, detached homes in Tyler, TX that were constructed as lab homes at the University of Texas–Tyler. Compared to the supply and balanced ventilation systems, exhaust ventilation showed the lowest uniformity of outdoor air exchange rate among living space zones. Timed indoor air recirculation by a central air distribution system helped improve the distribution of ventilation air drawn in by the exhaust system. It was also shown for the exhaust system that much of the source of outside air was not directly from outside as much of it came through the ceiling from the attic. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside air location, and fully distributing that air.