This article reports the results of an experimental study conducted in two classrooms at the University of Catania, aimed at verifying their acoustic quality in accordance with the UNI EN ISO 11532-2:2020 standard. The two classrooms have a different layout and are characterized by a different distribution of sound-absorbing materials, giving rise to significantly different acoustic responses despite having very similar volume. The measurements regarded the reverberation time, the speech clarity (C50) and the noise produced by the air conditioning systems. The work, in addition to highlighting in detail the methodological aspects in order to facilitate the reproducibility of the investigations in other buildings, including those of other universities, shows that the investigated classrooms – although characterized by good reverberation time – suffer from a lack of clarity and excessive noise of the air conditioning systems, mainly due to their inadequate balancing and conduction