What does the Silence function do and how do I activate it?

The Silence function reduces operational noise by running the compressor at low frequency, which may result in reduced cooling and heating capacity. To activate or deactivate it, hold the Fan Speed button for more than 2 seconds. The Silence function is cancelled by pressing the ON/OFF, Mode, Sleep, Turbo, or Clean button during operation. (Page 11 / Page 28)