All of them, but to be fair the bottom half of the rack is mostly multimedia gear that serves the whole house and a 6U gaming PC. I have venting into my ceilin

All of them, but to be fair the bottom half of the rack is mostly multimedia gear that serves the whole house and a 6U gaming PC. I have venting into my ceiling which connects outside but I am mostly using consumer gear like Raspberry pis and Intel NUCs and the rack fully fills the doorway so volume and heat is not a real issue.