An apparatus measuring the air change rate bythe tracer gas method was built at the Solar Energy Research Group of the Ecole Polytechnique Federale, Lausanne. Up to 10 locations can be measured simultaneously either by the decay method or the constant flow or the constant concentration method. This equipment was used to measure the air infiltration in various buildings. One of them was a three-storey one-family house, which was inhabited during the 12-day survey.

The measurements show that in such buildings, the air infiltration varies strongly from time to time, even when all windows and doors are closed. Moreover, strong exchanges between rooms are observed.

It is shown that, in multiroom inhabited buildings, the constant concentration method used during a lengthy survey allows one to obtain the total air infiltration flow rate. With only one tracer gas, the infiltration rates into each room are measured, but the exchanges between rooms can only be estimated qualitatively. Some effects of the inhabitants’ behavior are quantified.

Units: SI