A ventilation apparatus which forms a conventional ventilation system for controlling a discharge air volume has the following configuration.
Specifically, when a range hood is driven during 24-hour ventilation operation of a bathroom ventilation apparatus, a 24-hour ventilation function of the bathroom ventilation apparatus is stopped or a ventilation air volume is decreased. Further, when a current sensor detects stopping of a range hood fan, the 24-hour ventilation operation of the bathroom ventilation apparatus is restarted or restoration and increase of a discharge air volume are performed (refer to PTL (Patent literature) 1, for example).
As other patent literatures relating to the present application, PTLs 2 and 3 are listed.