The mathematical model of aerothermodynamic processes for combined heating-ventilating system as an object of automatic control has been developed. In the heating-ventilating system, the supply air comes from the central ventilation unit at its constant temperature. Regulation of the supply air flow is carried out by the special terminal, and additional change of its temperature is made in the heat exchanger. The work processes taking place in the system are reflected on the functional scheme. The structural scheme of the two-circuit automatic control system for air heating has been constructed. In general, the system provides various regulators for the flow rate and temperature of the supply air. The calculation of the transient process in the system is performed when the set temperature changes in the serviced room. When modeling the system, MPC controller was used in the supply air flow control circuit, and PID controller was used in the temperature control circuit. By combination of controllers for supply air flow and its temperature, with optimal adjustment of their parameters, it is possible to improve the regulation quality indicators of the automatic air heating control system and, as a result, to ensure the increase of the efficiency of the heating-ventilating system.