The French regulation on residential building ventilation relies on an overall and continuous airrenewal. The fresh air should enter the building through the habitable rooms while the polluted air isextracted in the service rooms. In this way, internal air is drained from the lowest polluted rooms to thehighest polluted ones. However, internal pressure equilibrium and air movements in buildings resultfrom the combined effects ventilation system and parameters such as wind, temperature difference or doors opening. This paper aims to analyse the influence of these parameters on pollutant transferwithin buildings. In so doing, experiments are carried out using tracer gas release for representingpollution sources in an experimental house. Mechanical exhaust, balanced and natural ventilationsystems are thus tested. Results show the followings:- For all cases, internal doors opening causes the most important pollutant spread.- When doors are closed, the best performances are obtained with balanced ventilation.- Independently to heating and doors opening, pollutant transfer from lower levels to higher levelsof the building is limited in the case of balanced ventilation.- Pollutant spread is quite similar whether the whole building is heated or not.