Air flow through doors, windows and other large openings constitutes a major factor inbuilding ventilation. However, due to the complexity of the physical processes involved,relevant physical phenomena are not yet fully understood.The paper presents data obtained from five consecutive experiments concerning air flowthrough a large opening (door) connecting two rooms (volumes 28.3 m and 38.1 mrespectively) with different air temperatures. The experiments were conducted within thetwo chambers (Service and Test Room) of a PASSYS Test Cell, a fully equippedoutdoor facility for thermal and solar monitoring. The experiments involved the heatingof one room (Test Room) until there was a significant temperature difference betweenthe rooms. After that, the door was opened, and the mass and heat exchanges betweenthe two rooms were measured using the available equipment. More specifically, theexperimental data, corresponding to 30 sec -step records, concerns the measurement oftracer gas (N2O) concentrations, indoor temperatures, air speed and direction in themiddle of the door opening, outdoor temperature and wind speed and direction.This paper attempts a qualitative analysis of the experimental results as a first steptowards a more comprehensive study of the physical processes in operation in relevantphenomena.