11-29-2010, 07:16 PM
Is it ok to use the silver flexible insulated duct between two foor levels where it will be concealed and unable to access . I plane to run two 10" metal ducts and come off of those with the flex for the floor registers . Does the 2 - 10 " main ducts sound about right for 600 sq ft and reduce down to 8" about half way . The two 10" with one down each side will work better than a large one down the center because I cant get much larger between the floor trusses.