In many respects, these boxes are the gas guzzlers of home appliances. Although modest in size, they may be using as much electricity as a new energy-efficient refrigerator, a study last year by the Natural Resources Defense Council found. That's because the drives in the devices are running at full tilt, or nearly so, even when you are not watching or recording a show.
The best solution I've found so far is to plug the set top box, the tv and all the other entertainment equipment into a power strip and flip that switch off when you go to bed at night. Then you know how much power they are using when you and they are asleep - none.