Boy, some of the comments in this thread act are pretty devoid of reading...like the manuals..and interviews with Nest executives.
First, read the Wired article interviewing Tony Fadell. One of the things he mentioned is that he had to assign two of his people full time to working with Underwriters Laboratories just to wrap their brains around the regulations surrounding smoke alarms. It's a highly regulated industry, much like health care and building codes...don't think that Nest didn't think about all the regulations of this class of products before shipping. Not to mention it looks like Nest is launching this product in Canada, the UK and maybe elsewhere. And I'm sure that all of those countries have similar regulations.
Second, the whole thing about using the red wire for smoke alarm synchronization was a big deal...in 1985. Wireless communication makes this pretty obsolete. And its not like the Nest Protects need a lot of time to communicate an emergency around the house...say, milliseconds over WiFi? Once the specific emergency is transmitted, those Protects are going to be screaming for you to get out, and unlike old fashioned detectors, it will say where the fire is. And if WiFi is down from the start of the emergency, Protects use the 802.15.4 "ZigBee" low power wireless mesh standard which means they can do their job regardless.
Yes, some people have a lot of smoke alarms in their house. Good for you. If buying 6 detectors at once is too rich for you, buy two now, and more over time. If its not worth the cost, at least make sure the ones you have are active and functional.
But this product launch made me (and I suspect a lot of people) to take stock in their detectors. In my case, I have three. One battery operated Kidde that I installed six months ago. The other two 120v models probably came with the house 20 years ago...and are well past the date they ever worked. Which means I really only have one working detector in a two story house...and none are located in the bedrooms (and I was wondering why the one near the kitchen never went off!). Just getting me to think about it will result in getting a sale or three out of me. It's too important not to act.
One more feature...the Protect's motion sensors will communicate whether or not someone is home to Nest Thermostats. This is important since some Nest Therm owners have the problem that their Themostats aren't in traffic areas where the motion sensors will pick up traffic for the Auto-Away function. The Protects can increase the surveillance net of the house and make Auto-Away more efficient for those home owners, which helps to decrease energy costs.
The Nest manual specifically mentions that all smoke/CO detectors have a specific operating life before they must be replaced. And that includes the Protect.
Lastly, I'm pretty sure the firmware of these things can be upgraded for future tricks. How cool is that? It may be useful later on since the Protect's temperature sensors could be used to communicate back to the Nest Thermostats for more specific temperature control room to room.
Edited by Sevenfeet - 10/8/13 at 8:16pm