Abstract: A heating and ventilating installation for a motor vehicle includes a regulating valve for adjusting the distribution of fresh air, received from a fresh air delivery chamber, between a first duct and a second duct. The first duct contains a heating radiator, and the first and second ducts exhaust into an air mixing zone, which communicates with a ventilating air vent and a foot warming vent in the cabin of the vehicle. A temperature sensor is located immediately downstream of the heating radiator, and transmits signals, representing the prevailing value of the temperature of heated air in the first duct, to a processing module.