Abstract: An automatic control system for an exhaust fan of a room having a water dispensing conduit is disclosed. The system includes a control module that controls delivery of electricity to the exhaust fan to activate and deactivate the exhaust fan, and a sensor suitable for mounting on the water dispensing conduit. The sensor senses temperature of the water dispensing conduit and when a temperature above a predetermined temperature value is reached on the water dispensing conduit, the sensor transmits a control signal to the control module. The temperature increase is due to hot water flowing though the water dispensing conduit (e.g., a shower pipe). Upon receipt of the control signal, the control module activates the exhaust fan for a user selectable time period.