Product review (4 stars): The unit is extremely quiet and sucks out air like no tomorrow
Originally installed this unit as non-vented but I wasn't thrilled. It was a bit noisy and fumes/steam from cooking on the front burner would be drawn outward versus into the fan...maybe due to negative air pressure caused by fast moving air above the unit. Not a physicist so not sure. Anyways I bit the bullet, since I tried other units and had the same issues. So I cut a whole in the wall and direct vented to the outside. What a difference. The unit is extremely quiet and sucks out air like no tomorrow. Looks good works great. Only complaint is that the flap inside the vent duct - which I guess is  to prevent cold air or vermin from entering the house - made lots of noise when the fan was on medium or high, so I simply removed it. Problem solved.