What do you think it is?
Everybody knows that the air conditioner eats up electricity while it's running, so do the washer and dryer, and that refrigerator...but none of those match up with the amount gobbled up by your cable box!
Not the TV, and yes, that is an energy hog too, but the actual box.
There are approximately 224 million of them in the United States and, combined, they consume approximately the same amount of electricity as would be produced by four nuclear reactors -- enormous ones, running around the clock.
The L.A. Times reports that the boxes have become "the biggest single energy user in many homes, apart from air conditioning."
Don't know about you but I'm turning it off the minute I get home!