My grow dresser is 30"x18"x48" (LxWxH). Temps are between 74F to 77F Lights On. Temps tend to drop to 70F lights off but it really depends on the ambient temp of my room. I have a 80mm PC Fan on a variable controller for intake located at the bottom of the dresser on the side and its set on low. My exhaust is a 120mm 70CFM fan located on the back of the dresser near the top and its running full speed all the time. The grow dresser is very quiet. I also have some 80mm fans running on 5 volts inside the grow dresser to create circulation in the the grow space. This seems to work very well and everything seems to be dialed in