Here's what it's like to wake up in America's smartest home. More precisely, here's what it's like for Alex Hawkinson, CEO of two-year-old smart-home company SmartThings, to wake up in his newly retrofitted suburban Maryland home, in which every single light and power outlet, plus a dozen gadgets, are all connected to and controllable from the Internet.

Mr. Hawkinson stretches. The accelerometer inside the Jawbone UP fitness tracker on his wrist registers movement, and wirelessly communicates it to his iPhone, which passes...