Zoned heating system from disparate line-voltage and low-voltage thermostats

[SmartenUp]

I am new to home automation and curious to try it. After reading around I see Hubitat seems like a great place to jump in.

My first task is to make my home thermostats smart, but I am not sure the best way to go about it. Hopefully someone here will be so kind as to direct me down the right path.

I am working with an older home in the US that has in wall electric cadet type heaters, which do blow air.

• Most of the rooms are on high, line-voltage thermostats.
• The main room is on a low voltage thermostat (says 30 volt max on back and just has two tiny wires [red and white] coming from the wall), I am assuming this was done because that room has 4 of these heaters which would have been too much wattage for a single line voltage thermostat, and so this is some kind of relay perhaps.

I want to be able to

• set modes such as home, away, sleeping, vacation, and when those modes are set have each thermostat go to a specified set point
• control all this from a wall mounted traditional appearing thermostat
• also be able to check and control this remotely from my phone
• adjust an individual thermostat to a new temperature and have that setting hold until the next time the whole system's mode changes

I'd like to be able to

• trigger away mode when I lock a smart lock on my way out the door
• trigger home mode when I unlock the door via smart lock
• trigger sleep mode from a switch or button next to the bed (eventually hope to have that also turn off all the lights, lock all the doors and arm my alarm)

How would you recommend going about this?

The main issue I have been seeing is that the system includes both line-voltage and low-voltage thermostats. Otherwise something like the Stelpro Maestro would have been great.

My current idea is to use a combination of products

• for low voltage something like the zwave Trane XR524
• for the line voltage something like the zigbee Stelpro ASMT402AD

On the backend, I am assuming/hoping I could create some sort of rule set. So, for instance, if the Trane thermostat was changed to home state, that would trigger a change in the temperature set point on all the other thermostats. Same thing for away, sleep, etc.

Would something like this work?
How simple would it be for me to create this kind of setup, and how would I start?
Would I need particular apps or plugins to support the hardware, or as long as it has Zigbee or Zwave connection I can pair it to the hub and start making rules for reading the states and how to control them?

Also, I considered Sinope, as I see at least on their line voltage thermostat TH1124ZB it lists Hubitat under the "works with" section (though Hubitat is not listed on their low voltage thermostat page TH1400ZB...), however,

• from what I understand, Sinope works through a web based NeviWeb meaning the system would fail if internet went down or their cloud was down (though perhaps I am not understanding how that works, or that was the old version)
• It would lack a central controller where I could set the home/away/sleep state on the wall, which the Trane thermostat has (though perhaps I could get another device to serve that function?)

I would assume it is highly likely there is a more elegant solution than what I have come up with so far, so any suggestions are appreciated!

[reid.a.baldwin]

@SmartenUp

I want to be able to

• set modes such as home, away, sleeping, vacation, and when those modes are set have each thermostat go to a specified set point
• control all this from a wall mounted traditional appearing thermostat
• also be able to check and control this remotely from my phone
• adjust an individual thermostat to a new temperature and have that setting hold until the next time the whole system's mode changes

Most of what you are asking for is easily accomplished using Hubitat's modes and Rule Machine once you get smart thermostats installed. The exception may be controlling Hubitat's mode from the thermostat. Although some thermostat's have the concept of various modes like home, away, sleeping, etc., that information is not part of what is typically communicated to Hubitat.

@SmartenUp

I'd like to be able to

• trigger away mode when I lock a smart lock on my way out the door
• trigger home mode when I unlock the door via smart lock
• trigger sleep mode from a switch or button next to the bed (eventually hope to have that also turn off all the lights, lock all the doors and arm my alarm)

Most of this should be doable with a smart door lock and smart light. I don't think any of the smart locks distinguish between locking from the outside and locking from the inside. I've heard mixed results distinguishing between manual locking events and Hubitat commanded locking events.

@SmartenUp

Most of the rooms are on high, line-voltage thermostats.

I am not familiar with line voltage system like what you are describing, so I will not comment on that aspect.

@SmartenUp

The main room is on a low voltage thermostat (says 30 volt max on back and just has two tiny wires [red and white] coming from the wall), I am assuming this was done because that room has 4 of these heaters which would have been too much wattage for a single line voltage thermostat, and so this is some kind of relay perhaps.

Based on this description, you should not assume that any smart low voltage thermostat will work as a simple replacement for what you have. Two wires wouldn't usually be sufficient for both power and signal, unless some non-standard protocol is used. Is the thermostat battery powered? Is it an old-fashioned thermostat that doesn't need power? I recommend that you investigate how this is wired and hopefully physically find the relay that you suspect is there. You may end up wanting to run 5-conductor thermostat wire to the thermostat. Alternatively, you may end up deciding to replace that relay with a smart relay like a Zooz ZEN16 and not rely on the wire to transmit the signal. (That option would make your system dependent on your Hubitat for basic function.)

[Stephan.J]

Welcome to the community.

For your line voltage thermostats you have two options:

1. Replace with a line voltage zwave/zigbee thermostat. Here is an example:
   https://www.aartech.ca/stzw402wbplus/stelpro-ki-stzw402-zwave-baseboard-line-voltage-thermostat-120v-240v.html This example will not work if a fan is part of your heater, if this is the case try to find a thermostat that will work with a fan.
2. Install a zwave relay to control the heaters. I would use this one: Zooz Z-Wave Plus S2 MultiRelay ZEN16 with 3 Dry Contact Relays (20A, 1 - The Smartest House
   The relay above is actually 3 relays in one, so you could take care of more than one heater with the one relay. I would then control when the relay supplies power to your heaters based on rules made with hubitat that are based on temperature readings by smart sensors and other parameters you may choose. Since I would also like to manually turn on/off my heat in case the automations are having problems (it happens), I would also install manual switches to activate the relay to turn on the heat. The zooz mentioned above allows for this.

For your heater that already has a thermostat activating a relay, I would just replace the relay with a smart one (the one listed above would work) and then probably replace the existing thermostat with a switch (that would activate the smart relay), just so I have a back-up way to turn on the heat if the automations are not working as desired.

If it was my project, I would definitely go the route of relays and not a bunch of line voltage smart thermostats, but it is your call.

Note: Using the Zooz Zen16 mentioned above only makes your system entirely dependent on Hubitat if you choose to NOT wire in manual switches to activate the relay. Being able to wire in these manual switches is a core feature of the Zooz, so I would do that, just to make sure that if my hubitat went down I could still turn my heaters on and off manually.

[SmartenUp]

@reid.a.baldwin

Most of what you are asking for is easily accomplished using Hubitat's modes and Rule Machine once you get smart thermostats installed. The exception may be controlling Hubitat's mode from the thermostat. Although some thermostat's have the concept of various modes like home, away, sleeping, etc., that information is not part of what is typically communicated to Hubitat.

What about finding a wall switch with multiple buttons, and each one could represent a different mode? That might be a way to check / set the mode easily, though less traditional than a typical thermostat.

@reid.a.baldwin

I don't think any of the smart locks distinguish between locking from the outside and locking from the inside.

I know the Schlage connect can trigger different actions with the Ring alarm system depending on how you lock it (eg by pressing the lock button to lock doesn't arm the alarm, but using your pin to lock it does), though not sure how easily that can be isolated in HE.

@reid.a.baldwin

Is the thermostat battery powered? Is it an old-fashioned thermostat that doesn't need power? I recommend that you investigate how this is wired and hopefully physically find the relay that you suspect is there. You may end up wanting to run 5-conductor thermostat wire to the thermostat.

It's an old thermostat that is not powered so I think that is why. I don't see any extra wires where it comes out of the wall. I'm not sure how to find where the relay itself is, I didn't see any suspicious panels in the wall and don't see it in the crawl space. I suppose it could be mounted behind the heater? The other thing I realized is they make C-line adapters that can plug into a wall outlet to power, which I could probably do, and I heard an electrician can put in a jumper to solve the problem as well, though I don't really understand that.

@Stephan.J

If it was my project, I would definitely go the route of relays and not a bunch of line voltage smart thermostats,

I'm curious, why would you choose to do it that way? Is it more reliable, or just cheaper?

@Stephan.J

The relay above is actually 3 relays in one, so you could take care of more than one heater with the one relay.

I could be wrong, but I think the heaters are on one circuit in series already. Would there be much utility in wiring them in separately if each circuit contains heaters already all in the desired zone?

How hard is it to rewire all this stuff, are you pulling out drywall to get at it?

Thanks for the replies, that is informative and helpful.

[Stephan.J]

@SmartenUp

I could be wrong, but I think the heaters are on one circuit in series already.

I would think that any heater you have is at least 1000 watts. If you have several in series this would result in amperage values beyond what many smart thermostats are capable of. Since I don't know the wattage/voltage of your existing heaters and if they are wired in series, and if so how many on one circuit. I will reserve providing any recommendations.

Nothing I do in my house is ever because it is cheaper. If it was my house all those heaters would be coming out and a forced air system would be installed. So many advantages with air quality management with forced air, compared to electric in wall units. If a centralized forced air isn't possible I would be going with split units in strategic locations.

[reid.a.baldwin]

@SmartenUp

What about finding a wall switch with multiple buttons, and each one could represent a different mode? That might be a way to check / set the mode easily, though less traditional than a typical thermostat.

This would likely work for that purpose.

[nclark]

@SmartenUp

Also, I considered Sinope, as I see at least on their line voltage thermostat TH1124ZB it lists Hubitat under the "works with" section (though Hubitat is not listed on their low voltage thermostat page TH1400ZB...), however,

• from what I understand, Sinope works through a web based NeviWeb meaning the system would fail if internet went down or their cloud was down (though perhaps I am not understanding how that works, or that was the old version)
• It would lack a central controller where I could set the home/away/sleep state on the wall, which the Trane thermostat has (though perhaps I could get another device to serve that function?)

I would assume it is highly likely there is a more elegant solution than what I have come up with so far, so any suggestions are appreciated!

I have Sinope Thermostats, if you get the Zigbee ones, they are 100% local with Hubitat, you will not be using the Naviweb application at all. Hubitat has a nice driver that works great, there is also a community driver that adds a few functionalities that are not supported from the built in one and that is what I'm using (can display outdoor temps on every thermostat).

If you go with Sinope, let me know and I'll guide you if you need help. They are very nice thermostats indeed, I almost went the Stelpro way but fortunately I came across these before buying.

They have line voltage (3k and 4k versions), low voltage and heated floor versions.

[SmartenUp]

@Stephan.J

Nothing I do in my house is ever because it is cheaper

If not the cost then why do you find the Zooz relay superior to the thermostats?

@reid.a.baldwin

This would likely work for that purpose.

That looks great, thanks!

@nclark

I have Sinope Thermostats

I am leaning more this way now. What does it look like controlling the system for you? Do you log in to the Hubitat web page in order to change status on them, or do you manually adjust the thermostat on the wall if you want one room down and another up? I am not familiar with the Hubitat UI yet, is there some thermostat controller app you can use on your phone?

[nclark]

@SmartenUp

@nclark

I have Sinope Thermostats

I am leaning more this way now. What does it look like controlling the system for you? Do you log in to the Hubitat web page in order to change status on them, or do you manually adjust the thermostat on the wall if you want one room down and another up? I am not familiar with the Hubitat UI yet, is there some thermostat controller app you can use on your phone?

Once in Hubitat, you have the app "Thermostat Scheduler" that makes these very intelligent by having them on schedules based on the mode of the house, (morning, day, evening, night, away and more as you wish) So everything is pretty automated, I added in my dashboard for our weekend house a virtual switch to hold all thermostats at 10 when activated, and back to the scheduler when off. So when we know we are going down in the winter, we just open the dashboard, turn off the "hold switch" and when we get there, all is toasty warm. You could go farther than that with rules that turns them off when a window or door is open for more than x minutes, drop 1-2 degrees when no one in the room for x minutes, etc.

But I must add to this, all these functionalities are available with most thermostats that can be used with Hubitat, not just the Sinope. I just like these better for the look, form factor (smaller 3k version) and proportional heating system that keeps the temps within .5 degrees all the time.

[Stephan.J]

@SmartenUp

If not the cost then why do you find the Zooz relay superior to the thermostats?

@SmartenUp

I could be wrong, but I think the heaters are on one circuit in series already.

@SmartenUp

4 of these heaters which would have been too much wattage for a single line voltage thermostat, and so this is some kind of relay perhaps.

I second an earlier poster who stated:

@reid.a.baldwin

I recommend that you investigate how this is wired and hopefully physically find the relay that you suspect is there.

I don't know how your house is currently wired, how many heaters are on one thermostat, how many are not. What exactly you want to have at the end of it all. Why don't you just purchase an HE, purchase the devices you want, set it all up and see if you like it. HE is easily capable of doing the things you mentioned earlier (and a lot more). Device choice usually comes down to personal preference and how you want your system to look and work.

I do know that if I had several zooz relays, I could replace your existing relays with the zooz. (I am assuming you have existing relays from your earlier posts, but you have not confirmed). I could also take heaters that are currently in series from one of your thermostats and put them on the relay separately (the zooz has three relays in one). I could then wire your existing thermostats to the relays and everything would work without any hub installed. This would also allow for the use of almost any thermostat, and in an old house, I would want to keep the classic look.

When I decided to make the whole system smart, it would be as simple as joining the zooz relays to the hub. You would now gain all the functionality that you want in terms of temperature control and scheduling. You would also gain the ability to turn on individual heaters that were before wired in series. No need to turn on two or more heaters when the conditions that your define only require one. To summarize, the relay route would allow you to:

1. Put almost any thermostat you want on the wall. (wouldn't have to be smart)
2. Control each heater separately, even when several are on the same thermostat.

If the two items are not important to you, then by all means go the route of smart thermostats.

The other option, is to do both. If you have relays, you might as well replace them with smart relays, so you have individual control over the heaters. You can also have a smart thermostat, which would do away with the requirement to put temperature sensors in each room. The smart thermostat would send temperature to the hub. A lot of users already have temperature sensors in each room (usually because it is built into window contact sensors) so that is taken care of already. But if you don't have any devices, you are going to need a way to get temp readings in every room you have heaters.

Just replacing your existing thermostats with a smart thermostat (no relays) is the simplest and easiest way. If this is your first foray into home automation, it would probably be wise to just do that, especially since it sounds like your not that comfortable with wiring.