I have a fairly small cabinet under my TV, so I need to stack components. I've stacked VHS on top of the receiver, and a DirecTV receiver on top of the VHS (DVD is located elsewhere due to space). To be safe, I added an approximate 3/4" high x 1" wide x 2" long block under each foot of each component, just to create more air space. The blocks are painted black to blend in. The back of my cabinet is open. I have glass doors on the front that I sometimes open and sometimes not. It's worked very well. My components do not run hot.