The Nest Protect’s smoke and carbon monoxide alarm offers less annoyance and more clarity—a voice alarm identifies the problem (“There’s smoke in the kitchen”). If it’s just burnt toast, it can be canceled with a wave of the hand. When the battery is low, a message is sent to the owner’s phone. It comes in hardwired or battery models. MSRP: $129. NestLabs, 650.331.1127, nest.com