Just getting started. For my 2’x4’x50” tent, I have a 190 cfm fan being used to vent outside through a window. It’s a 4” fan with an 8’ long 4” diameter dryer vent hose. Now that it’s colder today I’m noting that cold air is making its way back into the tent. I thought the fan was more than adequate but maybe not. If it is adequate it could be that I haven’t insulated the junction with vent hose and window properly. Appreciate your thoughts.