Depending on your home size, the Wii U GamePad can or cannot be used around your house. Apparently, for best performance, the Wii U GamePad needs to be about eight meters or less from the Wii U console. In terms of how many feet the controller can be taken away from a powered-on Wii U, it’s about 24.
…Is there a limit on the distance that you can take the [Wii U] GamePad away from the system?
“There is. And it’s… Of course, when we’re generally giving limits on things like that, and I think the same thing can be said for the Nintendo 3DS battery life… We tend to be more conservative, because we’re looking at it from a performance perspective. What, really, is the range where you’re going to get the best performance out of that? And you’re going to get the best performance within a range of about… They had a very precise number at one point. In meters it’s like eight meters. In feet it’s about 24 feet. That’s for best performance.”
-Bill Trinen, Nintendo product manager