"Good suction" is all about air flow and air velocities. These terms describe the quantity of air passing through the ventilator during a certain period - the number of cubic metres per hour - which in turn is determined by the output of the ventilator motor. A simple rule of thumb is: The higher the motor output, the greater the air flow.
High air flow is not the same as high efficiency, however. Except possibly in theory. It is entirely possible in principle, for example, to suck out all the air from the kitchen with an extremely powerful motor. But that would not be a particularly pleasant environment in which to be present. Rule of thumb number two is thus: A large air flow leads to reduced pressure and a high noise level (and higher energy consumption, to which we will come later). It does not lead to high efficiency.
The importance of the air flow is instead a question of balance and harmony with the ventilation of the kitchen as a whole. Just as a bicycle clearly needs to have tyres of the right size and at the right inflation pressure, so a kitchen ventilator needs a well-balanced air flow, neither too high nor too low. So if someone tries to convince you that high motor output and breakneck air velocities are the same as efficiency: You now know better. What makes the noise?
The airflow of the ventilator determines how much air is extracted from the kitchen. The flow is measured as the number of cubic metres per hour (m3/h). The graph shows how excessively high flows create reduced pressure inside the kitchen. And in a relatively short time, too.
