In the present study, the odour emission of a new HVAC-system in an office building of the Technical University of Berlin has been investigated. The system was built as part of a research project to develop an HVAC-system, which emits low pollution to the supply air. The odour intensity of the air before and after each component of the system was assessed by a human panel. The sources of odour emission inside the system should be localized. The system is equipped with a frequency-controlled fan to vary the airflow rate. Variances in the airflow rate can influence the odour intensity of the supply air due to changes in the odour emissions from the materials (velocity at the surfaces, friction) and the ratio of emitting substances from surfaces to the supply airflow (dilution of the emitted substances with outdoor air). In this study the influence of the airflow on the air quality of the supply air is investigated. Besides the odour emission inside the ventilation system the impact of the quality of the supply air on the indoor air quality in the ventilated rooms is of major interest. Therefore, the perceived air quality (PAQ) of the rooms was assessed by a trained panel in this study. The tests have been carried out with and without mechanical ventilation. Since the other pollution sources in the rooms emitted from building materials and furnishings did not change significantly during the measurement period, the differences in the assessments are mainly caused by the HVAC-system.