Hood against external wall - external blower or not?
I've read many of the posts on ventilation, but I am still a bit confused.
We need a wall mounted hood for a 6 burner 36" range top. The range top is against an external wall, so the hood will duct directly outside. On the one hand it sounds like an external blower is the way to go, and yet I often read that with such a short duct, an external blower will not be much quieter.
My concern is smoke over noise, which is why I'm thinking a minimum 900 cfm with 8" duct, with the hood as deep as possible (21 - 24"). But if we can, isn't an exterior blower better even if it ducts directly outside?
There are no cabinets on this wall, so I'm looking at a chimney style hood. Any suggestions beyond what I've noted above? Right now I'm looking at a Broan model, 2 Bests, and a KA, all of which have an external blower as an option.