Ventilation rates and air tightness levels in the Swedish housing stock.

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. The ventilation measurements were performed dwing one month in each house/flat by means of the so called PFT-method and the air tightness of a sub-sample of 90 buildings were measured by means of pressurisation technique. Main results are that the ventilation rate is lower than 0.35 l/(s,m²) or 0.5 ACH in more than 80 % of all the single-family houses and more than 50 % of all the multi-family houses. Expressed in l/(s,inhabitant) around 50 % of all, both single- and multi-family houses, have a ventilation rate higher than 10 l/(s,inhabitant). The influence of age, construction year, ventilation system, renovation staatus and geographical region can be traced by means of a scheme of relativedifferences correction factors. The investigation of the air tightness of the houses showed mainly that newer houses are less leaky than older ones and that the prescribed maximum n50-leakage value, as stated in the Swedish Building Code, is reached only by the newest multi-family houses.