Noise levels generated by pupils talking and moving greatly affect teaching and learning process in primary schools. Teachers tend to raise their voice level in order to improve intelligibility under noisy learning environment, negatively affecting their vocal health. More efforts need to be done to study an educational method to reduce chatting noise directly involving occupants’ behavior. This study aimed to evaluate the effects on noise reduction generated by active involvement of the pupils in lowering their voice volume when advised by a noise monitoring system with lighting feedback, namely SEM (Speech and Sound SEMaphore). Monitoring campaigns were carried out over 3 scholastic years in 13 primary school classes (4÷5 for year) in Turin (Italy). The background noise level, L90, was measured in two conditions with the lighting feedback of SEM switched off and on. The comparison between these conditions was analyzed for the overall classes for a total of 550 cases. The results showed an improvement in 51% of cases in terms of decrease of L90 mean values when SEM lighting feedback was on, where the average decrease of the L90 mean values was of about 3.0, 2.7 and 3.3 dB in first, second and third scholastic year, respectively.