The "Normal" mode will hardly surprise you, after turning me on and making your settings, I will maintain the set speed and fan oscillation at the selected angles.

In the "Natural" mode I will simulate a natural breeze and in short time intervals I will change the air flow speed, replicating the wind action in your garden. 

In the "Smart" mode, I'll utilise my thermometer and adjust my power based on the temperature in the room. In this way, I'll combine all my features and you get the best combination of performance and quiet operation.

Noise levels for the individual fan speed settings:

1    37.7 dB

2    38.5 dB

3    38.9 dB

4    39.8 dB

5    41.1 dB

6    42.5 dB

7    44.7 dB

8    46.2 dB

9    48.6 dB

10    49.5 dB

11    53.1 dB

12    55.3 dB