Been doing the search already but wanted to start a new thread.
Planning to replace all my 10 year old hardwired smokes with new First Alerts.
My hope is to use hardwire to interconnect (code here) and use one F/A wired unit that is ST-compatible to get into my Smart things, wirelessly. I know I can likely do a dry contact of some sort and have electric access. Also running Konnected so I can tie in that way too…
Here’s a nice tutorial to use a relay to integrate a hardwired system with SmartThings. I haven’t used it but it’s nicely detailed. I ended up using ZCombo’s in a few places since the smoke sensor is of a different type than my interconnected hardwired replacements.
I have the First Alerts. I am going back to hardwired. The FA units do not interconnect. If you have 10 smoke alarms it is likely that some cannot be heard from other parts of your house. There is nothing in the FA units, or capabilities in ST, to turn on the other units. This is, in my opinion, a giant safety hole in the FA implementation. The safety of my family is not worth trading for an app telling me the alarm triggered. I will go the relay, or replacement smart battery route.
Another option is to use an acoustic sensor that specifically listens for the UL listed smoke detector pattern and just integrate that. It’s very easy in the US as there is a zwave plus one from Ecolink with a certified ST integration:
That way you can use any smoke detectors you like as long as they use the standard alert. No wiring required.
I have used both a relay and the Ecolink firefighter. The firefighter is the simplest and works great.
Edit- wired interconnectivity for smoke and (more recently) CO2 is required by code in my area. Wired relays work great if you have access to a good location to tap into one of the units. I figure that if you have interconnected units capable of smoke/fire and CO2 that you might as well integrate both capabilities. I feel that the cost of the parts to hardwire both capabilities in along with the time and effort to do so just isn’t worth it when you can easily just add a firefighter and just change the batteries on it every other year if not annually
If you go the Firefighter route and want CO2 alerts- just make sure to enable them