A system and a method of controlling a ventilation or HVAC system that is configured to provide an air stream having a comfortable contact velocity to an occupant seated in a vehicle cabin. The system includes a sensor to determine the distance from a discharge nozzle to the vehicle occupant and a controller to control the exit velocity and/or an effective diameter of the nozzle. The sensor may use ultrasonic, infrared, LIDAR, or RADAR technology to determine distance. The system may determine the distance from the nozzle to the occupant based on a seat location determined by a seat location sensor. The seat location sensor may be common to an inflatable restraint (air bag) system.