could it be the pipe installation? Improper installation of pipes will also lead to poor smoke exhaust effect, and if the air duct is U/Z/ shaped during installation, it will lead to poor smoke exhaust effect of fans.

or is it because of the selection? To choose a fan suitable for your kitchen system

It is recommended that you choose a high-quality manufacturer, and someone will help you choose-install-after-sales maintenance, so you don't have to come to Baidu to ask. As far as manufacturers are concerned, Detong can choose.