The Leviton humidity sensor and fan control automatically detects excess humidity in a room and activates the ventilation fan to lessen condensation which helps reduce mold and mildew. The sensor uses a microprocessor combined with state-of-the-art digital sensing technology to continuously monitor and manage humidity levels in areas of the home prone to condensation and mildew. It features user-friendly controls to adjust sensitivity, humidity level and time-out settings. The sensor can replace a single pole switch and can be used with most bathroom or ventilation fans or fan/light combinations. It is designed to fit within a standard wall and requires a neutral wire for operation. Contemporary in design, the humidity sensor and fan control is the ideal solution for controlling ventilation in areas of high humidity, dampness or rooms prone to condensation and mildew such as bathrooms, basements, laundry rooms and home spas. The sensor also helps reduce energy usage by automatically operating the fan only when needed to control excess humidity.