Component heat & placement

[blu-bee]

Hey all, new-bee here but have been doing some research and upgrading. I'm actually rebuilding our entire system today with a new HDTV display & blu-ray player. At any rate, I'm wondering about component heat and placement. We've got a cabinet with a glass door on the front and just about anytime I go to open the door to put in a disc or what have you it's like opening an oven door. Aside from rearranging the shelving so that the receiver has a bit more space to breathe, are there any guidelines as far as placement, i.e. having it on the bottom shelf, etc?