Abstract Data collected in an Italian ancient theatre were elaborated in order to compare subjective sensations evaluated by means of questionnaires to data measured in field. A simplified model, developed in a previous paper, was validated by using measured data and by comparing the results to data from questionnaires (PMV Q ). Questionnaire data vary in a wider range of values than measured ones, confirming a higher variability in the personal sensation due to the possibility of giving only whole numbers. Therefore the questionnaire PMV scale needs to be refined to a 0.5 increment (resulting in 13 values). When comparing data calculated with the simplified model developed by the Authors in a previous work to data from questionnaires, more reliable results in the prediction of PMV were found with respect to measured data. Finally, people who voted 0 were about 54%, while about 88% are in the −1 to +1 range, showing a good behaviour of the theatre, nevertheless a wide range of variability for data from questionnaires corresponds to the same value of indoor air temperature. For this reason the PMV questionnaire scale needs to be refined to a 0.5 increment (resulting in 13 values).