In a device for air conditioning a motor-vehicle passenger compartment, a control module adjusts electrical power supplied to a motor-driven fan unit delivering airflow to a condenser of the device. Means are furthermore provided for recording an air throughput passing over the condenser and produced, at least in part, by the motor-driven fan unit. A regulation module estimates a maximum value of the electrical power supply to the motor-driven fan unit, for a given air throughput, with a view to limiting the electrical power supply to this maximum value, as a function of the air throughput.