The selection of ventilation fans needs to consider the following aspects:

Air volume and pressure: The air volume and pressure of a ventilation fan are important indicators for selecting a fan, which need to be selected according to actual needs. For example, the ventilation volume needs to meet the needs of indoor air circulation, and the wind pressure needs to meet the needs of indoor air pressure balance.

Working principle: There are various working principles of ventilation fans, including centrifugal fans, axial fans, mixed flow fans, etc. It is necessary to choose the appropriate working principle according to actual needs.

Noise and vibration: The noise and vibration of ventilation fans are important indicators for selecting ventilation fans, and it is necessary to choose ventilation fans with lower noise and vibration to ensure the comfort of the indoor environment.

Installation and maintenance: The installation and maintenance of ventilation fans are important indicators for selecting ventilation fans. It is necessary to choose ventilation fans that are easy to install and maintain to reduce maintenance costs and time.

Energy efficiency: The energy efficiency of ventilation fans is an important indicator for selecting them, and it is necessary to choose ventilation fans with better energy efficiency to reduce energy consumption and operating costs.

In summary, the selection of ventilation fans requires comprehensive consideration of factors such as air volume and pressure, working principle, noise and vibration, installation and maintenance, energy efficiency, etc., in order to choose a suitable ventilation fan.