are you sealing off the gap between the fan and the hose? can you post any pictures for us to get a better idea of what you have? usually, you'd have an exhaust fan blowing or pulling air out from the top of the room. heat rises, so this is where it will be warmest. if you pull air out rather then push air in, you will create a slight vacuum in the room and keep any oder in the room, instead of pushing the oder out of any cracks.