The aim of this work is to investigate the energy and thermal benefits of using PCM in a controlled cooling ceiling system integrated in a ventilated room, with three Moroccan climates representing three different Köppen-Geiger's climate types. The cooling power is controlled to maintain indoor air temperature in a narrow range assuring thermal comfort without wasting energy. Physical equations are solved numerically using computational fluid dynamics by a detailed 2D transient simulation integrating real ambient temperatures of Fez (Csa climate), Ifrane (Csb climate) and Marrakech (BSh climate). The main aim sought here is to assess the capacity of the paraffin C13 PCM to enhance the performance of a cooling ceiling system integrated in an efficiently ventilated room. Simulations performed justified the suitability of using the paraffin C13 PCM with the three climate types evaluated from a thermal point of view represented by the decreasing of fluctuation rate of the indoor air temperature, and with the Csa and Csb climates represented by a saving of cooling power reaching 17.07% and 16.30%, respectively, from an energy-related point of view. •Numerical investigation on the validity of using PCM in a controlled cooling ceiling.•Using the Paraffin C13 PCM in cooling ceiling led to a significant energy saving.•Cooling power control is applied to confine air temperature in a narrow interval contributing to thermal comfort targeted.