Air movement in houses: a new approach.

Uses a multi-channel infra-red gas analyser to measure nitrous oxide tracer gas concentration at six points round a house. Combines concentrations to give overall house ventilation rates and to estimate the air exchange between individual rooms. The gas analyser is also used to measure air movement between the house and its roof (with 5 sampling points in the house and one in the roof). Results show that typically 20-30% of the air that enters a houseleaves via the roof space through gaps in the ceiling. Shows, by means of heatand moisture balance in the roof space, that the air flow through these gaps is the major mode of transport of water vapour from the house to the roof, but the air movement is less important for heat transport. Blocking gaps in theceiling will significantly reduce the relative humidity in roof spaces.