A total of 177 measurements have been performed in apartments in multi-story buildings without mechanical ventilation. The buildings comprised renovated and non-renovated buildings built between 1930 and 1960. Measurements of air change rate and relative humidity have been performed using passive measurement techniques including a passive multiple tracer gas technique, the so-called PFT-technique. In each apartment the main bedroom has been investigated separately. In addition, the occupants completed a questionnaire concerning their use of the dwelling.

This paper reports results from the ventilation and air tightness measurements in Swedish dwellings as part of the 1992 Swedish Energy and Indoor Climate Survey (the ELIBstudy). The indoor climate in a random sample of 1200 single- and multi-family houses from the Swedish housing stock were investigated. Among different parameters the ventilation and the air-tightness of the houses were measured.

To predict the thermal and indoor air quality performance of vertical displacement ventilation systems using two-zone modeling, it is necessary to account for the different nature of the air flow due to thermal and contaminant mixing within these zones. Two zone modeling of vertical displacement ventilation was performed assuming piston flow in the clean zone, uniform mixing in the dirty zone, and no recirculation between the zones except via heat source plumes.