Thermostat differences: CT100, CT100+, CT101, GoControl


(Sam) #8

I’m about to install a Radio Thermostat CT101; is there a specific device handler for it or does ST have one that will work?

I decided on this one largely because of the price. A Lowes near Nashville had them for $59 on closeout but that same night (this week) I found it on Amazon for $45.

Radio Thermostat CT101


I’ve had the CT101 from Lowe’s for almost 2 years, and have used both the standard ST handler and rboy’s handler. Both work fine, rboy’s definitely has more features and a better interface in the app.

However, I’ve had nothing but problems with changing the thermostat modes either from the device in the ST app itself, or from smart apps like GreenThermostat or WebCoRE… Seems like once I turn the thermostat off from within ST (device or app), I can’t get it to respond to commands until I physically go over and cycle through the modes again. It’s really quite frustrating when I am trying to manage the thermostat based on doors/windows being left open.

So, basically, if it’s nice out and someone opens the window(s) at home, the thermostat will switch to Off mode, but when everything is closed up again, I cannot reliably get it to change back to the prior mode (either Heat or Cool)

@TheSmartestHouse I’m wondering if the CT100 Plus would have the same issues, and, if not, would it roughly fit in the footprint of my CT101? If I could swap it out to get it functioning rock solid reliably, I would replace it in a heartbeat…


Have you checked with @RBoy to make sure it was not a handler issue? Have they tested the same rule with a different unit/model and confirmed it worked? Since we’re not sure if it was an actual firmware bug, it’s hard to say if the new model would fix the issue. If you’re willing to test it and try, you can purchase the CT100 Plus and return it if it acts the same way:


I did try going back and forth several times with the original ST handler and rboy, still seemed to show the same issues, been mentioned that it is probably a bug in ST with the firmware or something.

I would like to try the ct100+ and see if it has the same issue or not

( - Make your home your butler!) #12

That is accurate. Some of the older thermostats have an issue where if the thermostat is switched off then you need to manually switch it back on using the physical button. We have one such sample in our lab and have been studying it for a while. I personally I think it’s a just a defective piece as none of the others exhibit this problem and they are all on the same firmware version.

Many folks have emailed us and requested to support turning “off” the thermostat in our apps and this is one reason why we don’t (there are others but for another thread).

Unfortunately the only permanent solution is to replace the thermostat.

However this is what we suggest to all users. Instead of turning the thermostat “off” set the cool set point to 90 and heat set point to 50. This effectively turns “off” the thermostat without actually setting it to off and avoids your issue. It has other advantages also.

@TheSmartestHouse if you have a sample of the newer version do send it to us and we can test it out


No problem, we’ll send a sample out so this way you can verify if it displays the same issue or not


@RBoy @TheSmartestHouse do you know if the ct100+ has changed the reporting interval of the various thermostat status? (e.g. the fan state running, heat / cool actively running) I know the ct101 that i have seems to only update those states every 15-30 minutes or so, making it kind of useless to drive events based on those statuses.

( - Make your home your butler!) #15

The thermostat itself doesn’t report states AFAIK, what you’re seeing in the polling from ST, likely (every 15 to 30 minutes). @TheSmartestHouse has shipped us a sample to analyze (thanks), we’ll test it out and get back.

(Sam) #16

I just tried changing modes on my CT101 (I was out of town and didn’t want to risk it not behaving). I can cycle it from cool to off to auto to heat. I can’t go directly from off to cool for example - I need to cycle through to get to the mode I want. I can change the mode manually at the thermostat and it’s reflected in the app but it appears that in the app it continues at the point in the cycle where it left off. I can do more experimenting if that would be helpful.


@RBoy have you had a chance to test out the ct100+ yet?

( - Make your home your butler!) #18

Hey sorry, we’ve been backlogged. We’ve started testing it and it’s looking good so far. Will wrap it up and present the results by next week.

( - Make your home your butler!) #19

CT100 Plus (Z-Wave Plus) vs the CT 101 (Z-Wave)

Okay an update on this, we’ve been testing the CT00 Plus for the past few weeks.

Things we’ve tested with the CT100 Plus (using the Universal Enhanced Z-Wave Thermostat device handler):

  1. Pairing and exclusion with v2 hub - passed. (NOTE: this device is about 400+ ft from the hub and has a few Z-Wave repeaters in between and it works great)
  2. Response to ST configuration commands - passed (minor documentation bug in the manual but no impact on operation)
  3. Response to ST commands, turn Fan On/Off, switch modes between Heat, Cool and Auto, Temp up/down - passed (NOTE: We found that the CT100 Plus is MUCH faster to respond to commands than the CT101, infact we could send it 2-3 temperature change commands per second compare to 1 for the CT101)
  4. Update from Thermostat local changes, tested change in modes, changes to fan states, changes to temperature settings - passed (NOTE: Once again we noticed that the response was faster with the CT-100 Plus)
  5. Run time updates - This is an area where some of the older CT-XX thermostats had issues. With the CT100 Plus when the fan mode in Auto would change or the A/C mode would turn on/off (running to idle or vice versa) it would update the ST hub immediately. This is a significant improvement over the CT-XX/CT101.

Overall the performance of the CT-100 Plus is significantly better than the CT-101, it’s more responsive and appears to have fixed some of the issues with the older thermostats.

When there is a switch over safety cool down period for the compressor, it displays it more prominently on the screen (the old model just had a small tiny timer which left you wondering what it was).

Having said all that, there is a cosmetic difference in the design, I’m posting pictures here for your reference. It has a larger form factor (about 10%). The Menu and Mode button are now touchscreen, you need to click on the touch screen to change the mode (it appears on the top left where the time clock used to be). If you’re using ST you probably won’t use this much but good to know. There is a slight change in the display, you’ll notice that the time is no longer displayed by default with CT100+ on the top left corner. There is now a setting that when changed on the thermostat now allows you to see now just the time and humidity like the original thermostat but also additional details like day of week and time of day (see screenshots below).

Great addition to your collection @TheSmartestHouse

CT-100 Plus

CT-100 Plus with additional sensors displayed




Hi @RBoy, thanks for the testing and update! How is the mounting / wiring compared to the CT101? My wall is slowly turning to swiss cheese around the thermostat mounting point, as each time it’s changed, more holes go in the wall (Changed from original thermostat -> programmable thermostat -> CT101 -> CT100+?).

If the CT100+ is as reliable as it appears to be, I’m definitely interested in changing over to it!

( - Make your home your butler!) #21

From a mounting and wiring perspective the CT100 Plus is identical to the CT101. The screw fit perfectly in the same slots. The difference is in the casing cover which in the CT100 Plus is an external mounted cover vs the CT101 which has in integrated casing with removable top and bottom slots. See the pictures. The second one is the CT-100 Plus mounted on top the CT-101. Identical!

Side by side

CT100 Plus on top of CT101 (screws line up)

CT100 Plus casing


Are the mounts mechanically / electrically compatible? Could I pop the CT101 off the mount and attach the CT100+ to the existing mount?

( - Make your home your butler!) #23

Yes, you can replace it screw for screw, wire for wire

( - Make your home your butler!) #24

So an update to this, in my earlier note I mentioned that the CT-100+ doesn’t show the time/humidity on the screen. After working through it some more we found out that that 's isn’t entire true.

Radio Thermostat has changed the default layout of the screen and in the default layout the humidity/time isn’t shown. However there is a hidden setting (SimpleUI) that can be changed to bring back not just the time/humidity but also additional details like time of day (day/night), day of week etc.

Here is a screenshot of what the thermostat screen looks like with the additional sensors options enabled. (I’ll also update my review above).

In the latest update of the Enhanced Z-Wave Thermostat handler, we have added the ability to show/hide these additional details through the device handler settings.

@TheSmartestHouse FYI


I have just gotten into Smartthings and am slowly acquiring devices. I just obtained a CT-101-L from Lowes (for a very good price). I have not yet installed it and am reading everything about it before I install it. The following has me concerned though:

So, if I include the CT-101 in my z-wave network, I will not be able to change the temperature or other functions manually from the touchscreen of the thermostat? That would be a deal breaker for me. I was under the impression that any z-wave thermostat could be used as a regular thermostat in addition to having the ability to control it remotely via an app. Could someone clarify this please?


You’ll be able to adjust temperature from the thermostat as needed once you connect it to SmartThings, but you won’t be able to program it from the screen. The thermostat can only accept one program to run automatically so once it’s connected to SmartThings, that programming happens from the ST app directly, not from the thermostat screen. You won’t be able to set a back-up program on the thermostat in case SmartThings fails either because the thermostat won’t automatically exclude from SmartThings and it will think it’s still being controlled by the hub. To our knowledge, all Z-Wave thermostats work the same way since they can run according to one program only, not multiple auto-programs at the same time. Hope that helps!


Thank you for the clarification. That certainly helped clear up my confusion.