Blossommanswered grow question 4 years ago I had the same issue in a closet grow. I placed a 16" fan inside the rear of the closet, setting it at a downwards angle towards the gap of the door and the floor. You may be able to find a "sweet spot" by feeling how much air is coming out of the closet with the fan in different positions. I also tried the opposite by placing the 16" fan outside the closet to blow air in through the gap. Seemed to work better using it inside. You might also try using 2-6" fans one inside and one outside on opposite sides of the gap. Dropped my temps by a few degrees while also providing the much needed circulation.