I have a temp controlled unit that I have been experimenting with this for the past 2 months. I had an issue with too much humidity at the bottom and not enough at the top. So I placed two usb powerd fans at the rear, behind the shelves to blow upwards. I originally tried to run them on a timer for 5 min every hour, but that didn’t do the job, so now they run full time. So far I have noticed zero heat difference between top, middle and bottom, but the humidity has stabilized across the board. Cigars still smoke just fine. All loose sticks are in the bottom two drawers and all boxes the rest of the way up.