The paper relates to the determination of the influence of changes in temperature and relative humidity on the laboratory acoustic measurements results. A series of direct reverberation time measurements was carried out, applying different thermal and humidity conditions in the empty reverberation chamber and reverberation chamber with a sound absorber. The reverberation chamber is mainly used to tests aimed at assessment construction materials and products. The results of acoustic measurements and the related classification of construction materials and products ultimately translate into the comfort and acoustic quality of rooms with special requirements as well as living rooms. Based on the analysis of the results, the significance of the problem related to the influence of air parameters on the results of measurements was demonstrated. The effect of changes in temperature and humidity on the results of calculating the equivalent sound absorbing surface was estimated using the n-perturbation method.