I see the DVR models display internal temperature readings... possibly the hard drive temperature? I am curious about the HD stand alone boxes and clients with no HDD. They feel very warm to the touch even when offline. Not able to find in the settings an internal temperature to verify. I have 3 H24 and sitting on top of them 6 H25 and 1 C41 all stacked in a vertical row. Do I need to worry about putting fans in place, spacers, etc? They are in a wide open area in a basement, not enclosed in a cabinet. Thanks for the feedback in advance.