[greglepore]

Originally Posted by look 171

Get a muffler (Fantech makes a great one. They call it a silencer), goes above the unit up in the attic. It reduces 50-60% of noise. What you are hearing is the velocity of the air moving through the unit and I bet the ducts aren't insulated. Wrap insulation around the rigid pipes may help. For further noise reduction, mount an exterior motor that pulls air through the unit and remove the motor under the hood. I first learned about their mufflers at a builder show about 15 years ago. Now I install one on almost all the kitchens we built. I know which hoods make the most noise and few are very quiet like a Vent-A-Hood.

This. I learned about these when I installed my own hood in 2010 using a remote mounted fantec and an empty viking shell. The mufflers are amazing.