SmartExhaust Ventilation Control SwitchThe SmartExhaust is designed as a replacement for the bathroom fan and light switch, helping insure healthy indoor air quality as well as adequate bathroom ventilation. By using a microprocessor to monitor and control fan operation, a precise amount of ventilation can be provided There are two settings on the SmartExhaust switch, ventilation and delay. Ventilation is the minutes per hour that you want the fan to operate. Delay is the number of minutes