I am looking to change out my venting over the summer and replace it with the Selkirk DT vent. I want to add an oak to my inset, My stove has a zero clearance box and extends into my garage so the vent pipe goes through the roof of my garage and I dont want to make another hole in the roof. I know the parts I need and how to do it. My question is on the cap. How is the exhaust and the outside air separated. I would think that if they were close to each other there would be a potential to draw in the exaust from the stove and draw it in with the fresh air during a high wind? I like the fact that the air would be heated before it enters the stove and would cut down on the draft in the house. thanks for your help