We purchased a 48" wolf Range and hood. Our only option to vent external is between the wall studs down to under house into crawl space and through outside wall.

I have a 1200CFM inline vent.

Question:

How much CFM am I going to loose by going from 10" round to 3 1/2 x 14 rectangle and back to 10" round under the house. The total run of the rectangle is about 72" with a 90 degree and about 15 feet of 10" round.

Anyone ever vented range hood this way?