This work is concerned with measuring air flows between the floors of houses. A simple measuring technique is described in which two portable SF6 systems were employed. The design and construction of the portable system are presented. A comparison of air flow patterns in a superinsulated house and a standard house is made. Results showed that the air flow between the upper and lower floors of the superinsulated house was about 20 m3/h compared with 100 m3/h in the traditionally built house. The method has also been validated in the laboratory by measuring air flows between two small chambers using both the tracer systems and an independent flow device.