Activate Sleep Mode.
When Sleep Mode is active, the Air Quality Indicator LED is disabled. The fan speed will automatically set to a minimum speed lower than 'Low', which is nearly silent. The Sleep Indicator light on the control panel will remain on.
Note: PlasmaWave is automatically disabled in Sleep Mode, but you can press the PlasmaWave Button to turn it back on if desired.
If that didn't work: The unit has a Light Sensor for Sleep Mode. Ensure it's not covered and the room is dark enough for the mode to activate fully. Also, the Wi-Fi Indicator can be turned off by pressing the Wi-Fi button briefly.
Heads up: Do not place the unit in direct sunlight, as this can cause malfunction.