The Panasonic FV-CSVK1 Condensation Sensor is a module created for the WhisperGreen Select line of fans. Panasonic WhisperGreen Select fans can be customized by adding one of the brand's patented modules. Once installed, a fan with this module can detect and respond to changes in a room's humidity. When relative humidity and temperature reach a certain level, this module turns on the Panasonic WhisperGreen Select fan. This helps prevent mold and mildew as well as ensure a much more comfortable experience. An automatic 20 minute delay off timer is also activated by the installation of this module. Other modules for WhisperGreen Select fans include multi-speed with time delay, SmartAction motion sensor and a NiteGlow LED night light. When paired with the multi-speed module, the condensation sensor can also vary fan speed depending on moisture levels.