A laboratory for the study of residential attic performance under natural conditions has been constructed. In one of the test cells, with a flat ceiling, white shingles, and venting devices at the soffit and ridge, measurements were taken of air flow through the plane of the ceiling. A ceiling "hole" was constructed in the otherwise tight ceiling, consisting of a PVC tube, an anemometer and a direction sensor. Data were collected for a six-month period.

The heat loss associated with the external fabric of a building has been greatly reduced by the increased levels of modem insulation, but heating losses associated with cold external air flowing into a building via leakage points in the external facade are still a major problem. Some ventilation is necessary but a detailed knowledge of this leakage would enable the major heat loss routes to be blocked. A crack has been studied which has hot air of a known temperature and flowrate passing over it.