My range hood is the kind that recirculates air, why anyone ever thinks this is a good idea is beyond me. It keeps heat in the house, blows hot air in your face as you cook, and doesn't get ride of smells. I want to convert this to an exterior vent but i'm not sure what this involves. I was planning on running the duct work through the existing sofit above the cabinets, about 8 feet total but i'm not sure if there are any code rules/best practices for this and what i might need to buy. I'm already planning on buying a new vent hood, duct work, and the damper opening that goes on the outside of the wall. Anything else?