Heat rises. Everyone knows that, so why is it that DIRECTV’s equipment has vent holes on the side or bottom? It would seem so much more efficient to put the holes on the top, right? (Before you say it, the HR44 Genie DVR sure looks like the vents are on the top, but actually there is no electronic componentry under the vents. The real components vent from the side… the left and right edges are empty.
There was a time when DIRECTV’s receivers did have vents on the top. The D10 shown above and other receivers in that generation (which included the H10 and HR20) all prominently feature louvered vent holes on the top of the receiver. Why did DIRECTV move away from this design, which would seem to be better?
Two words: cat vomit. OK, that wasn’t DIRECTV’s actual reason, but it’s my reason anyway. DIRECTV found that putting top-mounted vent holes increased the amount of dust in the unit and also allowed… outside contaminants… to get into the box more easily. They also found that people stacked items on top of each other and that made the vent holes let useful.
As for my reason, yeah… set the wayback machine to the mid-2000s when my cat, who liked to occupy a position right to the left of the TV, saw fit to let loose with her lunch into a previously pristine D10. Those top-mounted vent holes let all that good stuff right onto the mainboard. I saw it happen and unplugged the receiver immediately. Back then, DIRECTV let you own your receivers so I was able to open the case and swab it with q-tips and alcohol for about an hour to remove the… evidence. It never really was right after that, though.
So yes, you are most definitely right. Venting from the top would be more efficient in a perfect world, but in the imperfect world of our living rooms, bedrooms, and cat habitats, venting from the side is better. Venting from the bottom does allow for more holes and is used when there is a large flat area that needs to be vented. When I see a piece of equipment that vents from the bottom, I usually put it up on a few blocks of rubber or something to increase airflow to the bottom. It’s probably not necessary, but it couldn’t hurt!