New to SmartThings looking for help: Thermostat plus multiple sensors?


(Karl Wyatt) #1

I just recently purchased my smartthings hub and i’m excited to start integrating. I’ll start by saying this “I haven’t done a ton of research before asking this question,” so go lightly on me. I have an old dial thermostat that i doubt is measuring temperature correctly and needs to be replaced.

Do i need to go buy an expensive fancy thermostat? In the main level of my house i’d rather at some point build a dashboard on a tablet to control everything. And i’d rather cool or heat based on a composite temperature rather than just where the thermostat sits. (or cool based on upstairs in the summer, heat based on downstairs in the winter).

I could essentially buy the cheapest compatible thermostat on the market and put it right next to my furnace, and then place temp sensors everywhere right? then i don’t need to have two displays (one thermostat one dashboard). Is there a benifit to having an fancy bells and whistles thermostat if you have a smarthub working with other devices?

eh, hopefully what i’m asking makes sense. Thanks in advance



As far as dashboards go, take a look at the very popular smart tiles. Created by members of the community, it has grown into one of the most helpful tools for using SmartThings. You’ll find lots of discussion of it in the forums, or you can go straight to their site:

Regarding your thermostat project, I think either way can work. You can get a very inexpensive connected thermostat and use multiple sensors, but one of the issues with that is that in general the less expensive the sensor, the less accurate the temperature reporting. Many inexpensive sensors have a plus/minus of 4°F – – that can be too wide a range for thermostat control, where most people want a plus minus of no more than 2°F.

The other way is to use the Ecobee. Very nice smart thermostat intended for exactly this kind of use case (multiple sensors, one thermostat). @yvesracine has created several very popular smartapps for this device that handle different kinds of features and integrate well with SmartThings. The following is a good news story on using Ecobee with SmartThings:

One of the best things about SmartThings is that there are typically many different ways to solve the same problem, which gives you a lot of choices. People have different budgets, different aesthetics, different preferences and priorities. Some people like the challenge of hacking together their own solution. Others want to Just Buy something that works. Choice is good. :sunglasses:

p.s. As it happens, Ecobee is running a Father’s Day sale right now at what I think is the lowest price ever: $199 for the thermostat plus one extra sensor. Or you can get it with three sensors for around $260.

(Yves Racine) #3

Hi, there were several threads about the “cheap” z-wave/zigbee thermostats vs. smart thermostats
like ecobee.

I did a summary of those threads here:

In brief, it really depends on your needs: if you have a small appartment, a cheap thermostat will be
enough; if you have a large house and want to be able to support more requirements (ex. zones), then a smarter thermostat is much better.


(Karl Wyatt) #4

I’m getting around to reading these :slight_smile: i appreciate the input.

If the Ecobee can do most of the smart work on its own, what is the use of the Smart Thing? Maybe i’m thinking about it wrong?

Let me know if i’m on the right track with some of the things i’m thinking i can do. I would like to get a couple of window or door sensors and then be able to say “if the door is open, don’t heat\cool even if the schedule says i should.” my wife is big about saying “its a nice day out” opening windows and forgetting to turn off the heat or air. :slight_smile:


(Yves Racine) #5

Hi @karlwyatt,

When you deal with cooling/heating your home, you want the best scheduling available, and the ecobee scheduling is much better than ST. This way, if there are any ST issues (as you may know by now, it happens sometimes…), your thermostat can still operate and will heat/cool your home (it can be a safety issue here especially in Summer/Winter).

The basic idea is to manage any exceptions to your normal scheduling in ST, and my automations are built upon this principle.

I’ve created many automations and divided them into many smartapps as I want to create as many independent & dedicated services as possible.

This way, each “micro service” can be modified & tested independently from each other: this design approach allows faster changes and less ST related platform issues (instead of creating a big smartapp that does everything and requires more maintenance).

The end users can also pick and choose the automations that they really need to meet their own use cases.

Here are some use cases (and the related smartapps):

1- Set your thermostat to ‘Away’ when you’re not home

See the EcobeeChangeMode smartapp.

2- Resume your normal scheduling when you’re back home

See the EcobeeResumeProg smartapp.

3- Turn off your thermostat(s) if your window or door (contact sensor) is open after x minutes

See the WindorOrDoorOpen smartapp

4- Adjust the ecobee setpoints based on any ST connected temp/motion sensors and/or outdoor sensor (or weatherStation)

See the MonitorAndSetEcobee smartapp

5-Orchestrate your smart vents in conjunction with your ecobee’s setpoints in order to achieve the best comfort and energy efficiency by creating virtual/physical zones.

See the ecobeeSetZoneWithSchedule smartapp

6- Control your indoor humidity using your humdifier/dehumidifier/HRV/ERV

See the MonitorAndSetEcobeeHumidity smartapp

7- Set a different mimum fan time for each of your ecobee climate

See the ecobeeSetFanTime smartapp

And, much more…Most of my smartapps are available at my github or available at my store:

For more details, see this thread:

P.S. My smartapps work only with MyEcobee device, the most comprehensive ecobee implementation in ST.


(Kevin) #6

I went with a cheaper zwave thermostat because the room our thermostat is in is rarely used dining room. So (1) I’d never see the pretty $300 thermostat and (2) the presence sensor would never work since we aren’t in that room very often.

I bought the CT100 which seems to be popular, but I might have selected something else now. CT100 input voltage with the Common wire has max spec of 25VAC, my HVAC goes to 27VAC. Other smart thermostats have a max input of 30VAC. The display of the CT100 is kind of confusing and large because of all the separate elements in the display. There are other similar models that have the typical display and buttons for quick temp changes at the thermostat.

Also search for “thermostat smartapp” and you’ll find several choices for adding remote sensor features to a cheaper smart thermostat. I haven’t tried these…

(Yves Racine) #7

Hi @kevin,

Sure, different use cases, different solutions (and you need to take into account your budget of course).

That’s what I wrote ealier,

Continuing the discussion from New to SmartThings looking for help: Thermostat plus multiple sensors?:

BTW, the ScheduleTstatZones smartapp was created by me and can use many remote sensors to average out the temps & adjusts the setpoints at your thermostat.

However, with a “dumb” thermostat, please be aware that:

  1. You are totally dependent on the ST scheduling (which is much better now, but still not reliable from time to time)
  2. You do not have the smart “features” of a smart thermostat like “Smart Recovery” and many others. See the link at the ST community wiki for more details.

( - Make your home your butler!) #8


Like said above, for absolute basic thermostat capability, if that’s your only need then using a standard thermostat may be better due to high dependencies on the platform. The pure power of the platform comes into play when you start doing interesting things like connecting the thermostat to external motion sensors, temperature sensors etc.

Check out these two other ones:

(Chris Fichter) #9

Don’t let the voltage issue sway you. It will be fine. I have a CT 100.

(Karl Wyatt) #10

Well you convinced me and I bought the ecobee3 w/one remote sensor. Is there anyway now to add temp to my smart thing dashboard? Right now I just have smoke.

(Yves Racine) #11

Hi @karlwyatt, do you want to add a remote motion sensor to SHM?

If so, you need to press the ‘gear’ icon at the upper right

  • add a custom monitoring rule
  • press on new monitoring rule
  • What kind of device? Select motion Sensor and then enter the rules you want (frequency and more options).

However, you do not need to add the motion sensor to SHM to see it under MyHome/Things or
MyHome/Rooms (if you added it to an existing room).

BTW, are you using MyEcobee device or the stock ecobee device (from ST)?

MyEcobee device has much more features than the ST stock device, see the list of smartapps
at my github:

My Ecobee device is only available at my store for download:


(Karl Wyatt) #12

I’m looking just to add temp to my dashboard.

As far as the app I signed up on ecobee and setup the thermostat that way. Then I connected it via add device in ST

(Yves Racine) #13


The ST stock device exposes not even 10% of the ecobee APIs.

MyEcobee device is different from the ST stock device (the one available through Connect).

There is no other thermostat device that exposes so much capabilities to ST (compared to Nest, Honeywell Lyric and any other smart thermostats). If you want to unlock all ecobee features available through the APIs, you’d need MyEcobee device.

See my post above:


(maurice dudeley) #14

ecobee3 smart thermostat is a good choice with 5 sensors to monitor the temperature in multiple rooms.