If you have a poor air flow in the hood, then the reasons are:
Clogged filter for cleaning the exhaust hood
Clogged ventilation duct
No air flow into the room
The hood is too high
Insufficient performance of the exhaust fan
Change fan filters. Remove dirt from the grate. Use a mirror to check the channel, it may be dirty. Also, a fan with a non-return valve on the ventilation duct can help with weak draft. If you need help with high end range hood repair, call us right now!