They are unlikely to strengthen your Z wave mesh, if that’s what you were thinking, for the reasons in my previous post. In that sense there is no difference between hardwired and battery operated for most smoke detector models.
As far as why they don’t exist yet in the US, I have some guesses, but no hard information. I suspect it’s because it’s only recently that zwave itself could be UL approved (I believe the ring security system was the first zwave security system to get a UL listing), and that would have limited the market.
They’ve been available in the EU for a number of years, Fibaro had one for a while, but again, only for the EU.
Anyway, the ecolink firefighter acoustic sensor has been a good way to bring UL listed smoke detectors into a zwave home automation system. That device just listens for the standard smoke detector alarm pattern and alerts on that. It’s been quite popular in the community. It’s a battery powered device, and not a repeater, so it doesn’t help with that aspect.
As far as improving the strength of the z wave mesh by adding more repeaters, the usual choices are zwave smart plugs or light switches. Both are typically also zwave repeaters.
Zooz has a kit now that links into hardwired interconnected smokes. Similar to what many have done with an Ecolink sensor except powered from mains, so no battery to change and no concerns about separating low/high voltage. My project this weekend will be installing one (though I opted for the BRK relay, purchased separately from the Zooz ZEN51).
Currently we do not have a hardwired ZWAVE product in development.
I followed up, asking what happened, as I did have two reports it was being worked on. And I got this…
I cannot say for sure. I was simply given the answer from our corporate contact that we don’t have a hardwired version of the ZCOMBO being developed. It’s possible it may have been a project that was dropped, but that is speculation. Internal company development details are not normally public information.
I think the Zooz option listed above is now the best solution, and I marked it as such. Too bad it doesn’t have a battery backup though.
Maybe BRK/First Alert will come out with a Matter one someday. In the mealtime, if some of you swarm their customer service contact with requests for this, maybe they will change their minds.