A year later, have you heard anything about NEST Protect compatibility?
I don’t see a reason why if they integrate the thermostats they can’t integrate the smokes. At my own home, I have First Alert detectors and use the relatively new 2GIG ring pass through connector to signal my GC3, but the NEST Protect offers some good benefits. Using the audio-based FireFighter wouldn’t work with those. Unfortunately you would have to replace every detector because they won’t use the wired system.
It looks like the First Alert product that uses the signal wire is compatible by using the ring and you don’t have to replace every single one of the detectors. However, the FirstAlert NEST Protect competitor doesn’t seem like it’s quite as good.
Hopefully there would be a way to integrate NEST Protect to the GC3