The ducting may run horizontally or vertically depending on your type of hood. Island hoods must vent through the ceiling, while wall hoods can vent through the wall or ceiling.
Is higher or lower CFM better for range hood?
The power or air movement for range hoods is measured in cubic feet per minute (CFM). ... For example, if your high-output burner output is 45,000 BTU, look for a range hood that provides 450 CFM to best clear the air. However, the higher the CFM, the louder the hood will be.