Turn your Bionaire humidifier on. Check the filter monitor located next to the moisture outlet. If the light stays on 60 seconds after being turned on, it is time to change the filter.
Turn the humidifier off and unplug the unit.
Open the filter door by lifting up the tab on the left side of the filter door.
Take out the wick filter you find inside and throw it away.
Insert a new filter in place of the old one. Close the filter door.