“Type of external duct My existing hood-your brand- has a 3 1/2 x 10" vent, to connect to exterior duct vent. It is centered. I need to replace the new one which has no drawing power. ie it has no sucking power. I bought it new to replace a Nutone and is useless. I need one with more sucking power. ie more removal cfm. Can I order it via my building supply store O.C. Cluss?”