Water panels are the "heart" of your whole home humidifier, making it possible for water to be evenly dispersed and evaporated into your home. Through time, the pores get clogged with scale and mineral deposits from your water, making it difficult for the water panel to do its job. To keep your humidifier in good shape and ensure proper performance, it is recommended that you change the water panel at least once a season, more if you have hard water.