Hi newbe here, looking to buy stove propane looking at lopi but question about stove pipe. theirs is a doulbe liner one 4inch exshust surounded by the 6inch so call for fresh air does this work? Instead of taking air inside your home to help fuel the fire it takes from outside. What about cold cold weather trying to warm up cold cold air?. any more or less down drafts or blow out in poilit lights. any help would be great.. thans buyer..