Which Thermostat with OpenHAB?

Hey,

There are couple of Thermostats available from different Brands like Homematic, Comet, Honeywell, etc…

What are you using? Do you control each Thermostat or do you control the Central which forwards to Thermostat?

Thanks for your helps.
Regards

I have four thermostats spread across two continents, two Ecobee and two Nest, and I use a combination of openHAB and their native mobile apps. But a good answer to your question depends on your geography and heating/cooling equipment.

Hi,
I have a wall mounted thermostat from homematic. Big advantage: It fit´s into the Gira series, I have all over in my house. It works fine with an associated window sensor and a thermostat at the radiator.
I had the same set-up in my pevious house in the child´s room and it worked without any issues for more than a year.
Another advantage: it shows also the humidity.

Hi,

i have nearly the same setupup like @Knallfrosch but only one room with wall mountes thermostats. @watou setup seems a liitle bit uncommon (2 continents). But yes geograhie and heating Equipment ist a decission part but don’t forget other items like switches etc. Which system is in use there or should be used later (Bidcos, ZWave, …)

Thomas

I’m using the MAX! thermostats, as do a couple of people over here.
Essentially they’re the same as the HomeMatic units (it’s from the same vendor), yet cheaper.
They come with a server & web UI where you configure the temperatures. You can link some of them together to form a room, but other than that, you need to individually control them.
But you can do so from within openHAB using the maxcube binding, so in total, openHAB is my thermostat control Central.

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I’m in the US and have a Nest (got one free from my power company). If I were to buy one I would probably go with Echobee or even something less smart and connected. I’ve turned off the learning feature of the Nest and drive the whole system from OH rules, partially because I only have the one furnace for the whole house so I only have one Nest.

I augment this with some DIY temp sensors running on Arduinos throughout the house. My rules use a combination of the Nest’s set temp and temperature differentials between the three floors to drive the HVAC. I don’t have air conditioning so running the fan in the summer when the basement is a good 10 degrees F cooler than the top floor is a life saver.

2gig CT100. Use zwave to talk to it. LOVE IT!!

I use an EcoBee myself. I’ve been very happy with it’s integration into OpenHab and it’s performance overall. Clear installation instructions are provided. I selected this one though because of its use of remote occupancy sensors and temperature monitors. My thermostat is stuck in a location where there is rarely anybody physically in that area. This renders the Nest fairly useless as it would think my house was constantly empty. EcoBee solve that with the remote sensors. Furthermore the binding allows you to see the values from all of those sensors too, not just the temperature at the thermostat.

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Actually the latest version of the Nest firmware/phone apps use wifi and geolocation from your phone to augment presence detection. So that problem is not as big as it once was.

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That’s smart. I didn’t know that.

I use Venstar and love it. App works well, and I control it all is OpenHAB. It has a JSON based API which makes calls to it and reading data from it simple. Someone could build a binding if you really wanted to, but not necessary.

I’m planning to use this thermostat to control a PLC through openHAB/raspberry Pi. Could you use the max! Thermostat to control external devices or only the standard max! Valves?

Rather than recommending a certain brand, I’ll just recommend this: Select a thermostat that you can control directly either over your LAN or some other type of local control. (You can also apply this advice to ALL IoT devices)

With the Nest thermostat, for example, this is not currently possible. The OH binding controls the Nest over the WAN API they have set up. So, if can be laggy at times, it is dependent on them running their server forever and if you drop your internet connection, you cannot control it (other than by turning the dial by hand). The Nest does have the possibility of local control as it has several radios built in, and Google has created an API (Currently I think called Google Thread) and this is used by the Nest smoke detectors and some other “Partner” devices, but isn’t currently available for anyone outside of their circle.

I think the Nest is a very nice thermostat, just somewhat constrained by the company’s desire to try to force people into their ecosystem and control the data. Although this is the problem with all of IoT at the moment…

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Nope. MAX! thermostats control themselves and noone else. Even the MAX! cube is just for provisioning.

I’ve setup own ‘thermostats’ myself for my floor heating. Actuator-connected motor valves, effectively. Both, the major drawback and at the same time major advantage are that you have to do, but can do the programming yourself.
There’s nothing in life for free :slight_smile:

So it is not possible to control the GPIO of the raspberry pi with the Max! Thermostat by setting up a rule through OpenHAB?
An expensive z-wave thermosat would make that possible or is it inevitable to program your own just like you?

That would be arduino like thermostat i guess, or how did you do it? I’m curious :slight_smile:

Verstuurd vanaf mijn iPhone

Huh? I guess you mean the opposite, to control the thermostat with (through) the GPIO.
A smart/classic thermostat is a combined valve-thermometer unit with (smart) or without (classic) CPU+software to take care of opening/closing the valve based on current temperature it measures itself (and target temperature submitted via whatever control channel).
I just connected a valve to a (zwave) on/off actuator. (yes, you could also use the GPIO, but you need a relay and a cable connction). No thermometer directly involved (of course there are thermometers, i.e. sensors to deliver temperature values for the rooms which I then use in my control software loop).

If i’m right you set the on/off z-wave actuator by your max! thermostat (ON when there is heat demand, OFF when not) and through the control software in OH.
I mean to set a GPIO from the Pi high (when there is heat demand) or low (when there is not) with the Max! room thermostat. The GPIO will be connected to a digital input of a PLC. The PLC gets the high or low output from the GPIO and decides to set on the heating program or not. Did i make it more clear now? Is that possible?

Not at all. What’s PLC? How do you mean to set GPIO high based on Max! room thermostat ?
(well of course you can do that based on the temperature it shows, but you can use any thermometer for that purpose …)
And you cannot turn the MAX! valve. It has no electrical input, you can just control non-MAX thermostats (valves) through either GPIO or zwave.

Hi Markus,

 I have the same configuration installed (Actuator-connected motor valves to control my floor heating) and I'm looking now to create my own thermostat.  
I will appreciate if you can send me your OH configuration (items, rules ...) in order to have an idea what and how to do it. 

Best Regards,
Marian
maryantudor@gmail.com

Items depend on the actuator/sensor tech you’re using. I’m using zwave actuator to control the valves via 220V actuator switches, and (multi)sensors to (also) deliver temperature values. See zwave binding docs for examples.
Rules, well, they’re individual.Something with a core like if (temp < threshold) valve.sendcommand(ON), but you’ll have to do the programming on your own.