Patent ID: 7455583

Claim:
A ventilator comprising: an exhaust fan motor, which is a direct-current motor, for ventilating room air, a human sensor for detecting the presence of a human body, a control unit for controlling the exhaust fan motor by receiving a signal from the human sensor, and an air flow rate adjusting unit for adjusting the ventilation flow rate by the exhaust fan motor, wherein the control unit operates the ventilation fan motor at a fixed flow rate for a specified time when detecting a signal from the human sensor indicative of the presence of a human body, and operates the ventilation fan motor at a ventilation flow rate adjusted by the flow rate adjusting unit all the time as ordinary operation when not detecting the signal, and in the ordinary operation, the ventilation flow rate can be adjusted steplessly or in multiple steps at small intervals by the flow rate adjusting unit, wherein the control unit, when receiving a signal from the human sensor, measures a user staying time, and varies a ventilation delay operation time after a user leaves the room on the basis of a cumulative time calculated from the user staying time, and wherein the control unit, when receiving a signal from the human sensor, measures a user staying time, and controls the ventilation flow rate during ventilation delay operation after a user leaves on the basis of a cumulative time calculated from the user staying time.