A combined windcatcher and light pipe (SunCatcher) was installed in the building of theSchool of Construction Management and Engineering in the MSc Seminar Room (2N09).Monitoring of indoor environment in real weather conditions was conducted to evaluate theperformance of windcatchers in the room and to conduct occupant survey. External weatherconditions and internal indoor environment and air quality indicators were recorded. Thetracer gas decay method using SF6 was used to establish the air change rate for variousconditions. The results indicated that, the ventilation rate achieved through the windcatcherdepends on wind speed, wind direction and temperature difference between room andoutdoor. The indoor air quality parameters improved due to the installation of thewindcatcher. The measured air change rate was between 1.5 and 6.8 ac/h. Occupantsquestionnaire showed 75% of the occupants were satisfied with the internal conditions andrecommended the installation of the system in other buildings in the UK.