The air exfiltration part of ventilation is often difficult to determine and its part of the energy balance is therefore usually determined as a remainder or given a constant value. This paper examines ventilation systems in six different modern houses. The constant concentration tracer gas technique tended to underestimate the total ventilation. A simplified theoretical one-zone model made accurate estimations of the air exfiltration. For detailed information on air flows a multi-zone network model was useful.
The paper compares air infiltration rate measurements with air leakage measurements in a modem industrial building. In each case the tests have been performed firstly with the building 'as-built', and then with the major leakage components sealed. The building investigated was of a cladding wall construdion with U-values of 0.6 W.m^-2.K^-1 for both the walls and roof. It had a floor area of 466 m². The volume was 3050 m³. Tracer decay tests and constant concentration methods (both using N20) were performed in the building to establish the air infiitration rates.
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