Shelfy has 3 modes of use:
You can change modes via the button or the Vitesy Hub app.
In the app you will just go to the section with the fan icon and set the mode to Eco, Crisper or Performance.
Otherwise, you will just press the button 1 time to switch to the next mode (the order is: Eco, Crisper, Performance).
The mode you choose greatly affects battery life, check out the dedicated FAQ to learn more.
If you feel like Shelfy's fan speed does not react immediately, don't worry! Remember that Shelfy works in purification cycles.
NB. A more intense mode (Performance) does not result in improved air quality displayed in the app, as it is based on different factors. Read this FAQ to learn more.