CT30 Thermostat and Power Requirements

New to Smartthings and just set my hub up with a Kwikset 910 lock (more devices arriving in the mail soon). I need a thermostat and was originally considering the CT100 but just realized that the CT30 will do the job just as well. My question is do I need the C-wire for it to work with Z-Wave? I don’t have a C-wire and would use the batteries. The box itself offers conflicting information on this. If it does work with batteries, how long can I expect them to last?

If the CT30 is any similar to the CT100, the C-wire is not required, but strongly recommended. I have CT100’s set up in both configurations (with and without C-wire): the one with C-wire has been running for the last 13 months without any need of battery change (still reporting 100% charged), and communication with the hub is very precise and reliable at each polling event; the ones without the C-wire require battery change every 1.5 months (I ended up switching to rechargeable batteries), and the communication is a bit iffy (at each polling operation, at least some of the requested reports is actually not processed).
So, if you can, I would strongly recommend setting up the C-wire; otherwise, the system is still usable, but it requires a bit more patience.

Minollo is entirely correct. The CT30 performs just like the updated model, the CT100. I originally had my CT30 powered only with batteries and they lasted about 2-3 months and the response time was very laggy. To the point that my wife would get frustrated and I lost points on the WAF (Wife Acceptance Factor).

I ended up running a 24-volt power adapter scavenged from a defunct device, through the wall behind the unit to supply power, and the change in response time is very noticeable. I can’t yet comment on the batteries because its only been a few months.

I would strongly recommend connecting the power adapter if there is any way possible!


Thanks for the advice! So my hub is literally 12 feet from the thermostat with zero obstructions in the way. Do you still think I’d notice some lag? I’m getting crazy lag from my Kwikset lock but that’s about 30 feet away with two thick brick walls between them (hoping a light switch I’m adding in the middle will help repeat the signal).

Yes, you would still notice communication problems. As DavidCreed said, if in any way possible, connect a power adapter - it’s worth the effort.

It’s not the distance that creates the lag, my thermostat was about 6 feet from hub. The thermostat doesn’t poll/receive as often when in battery only mode. I’m trying to find where in the documentation this is outlined. I’ll update when found.


It is actually weird; I have a scheduled poll() command which I trigger every 5 minutes to get fresh information from the thermostat (the thermostat is not very good at pushing changes pro-actively unfortunately), and the poll() command sends several report requests to the device (temperature, humidity, setpoints, …). My C-wire powered CT100 will reply with all the reports promptly, with each result 2 seconds after the previous one as per request; the battery powered CT100s will reply with much delay (several seconds to minutes) and only to a few requests, rarely all of them… Still usable, as after a few poll() commands I’ll end up getting the information I need; but surely flaky.

I have noticed no difference in behavior between the thermostat 5 feet away from the hub and the one 30 feet away on a different floor…

Went ahead and ordered the CT30 on eBay. If the batteries fail to provide the desired performance I’lll always have the option to wire it to an adjacent light switch.

Hi everybody,

I have a CT-30 with RapidSe USNAP module. When I add it to my ST, for some reason it identifies as “Fibaro door/window sensor”. Any idea why is that and how I can fix this?
anyman, did you good luck with the one you bought on Ebay? How did it go with adding to ST?