Using a system like openHAB there is no longer a need to shell out money for expensive fancy thermostats in every room. I currently have basic electromechanical units with a large hysteresis and internal feedback. They supply the needs of floor heating with its long delays and the system requirement for on and off times of at least one hour.

I would have expected it to be the first thing ever written for openHAB to replace these thermostats with simple temperature sensors and implement the thermostat function in software. In fact the room heatin is so far the only function I want to use openHAB for, playful extras may come later. Once the basic funtion is there you can add extras, like sensing opnen windows for ventilation, time of day control, override controls and whatnot. But the basic functionality was the first thing I expected to find here. Is openHAB not for me then?

On the contrary: I think you just hit the jackpot!
Ambient temperature control is something I am working with everyday! openHAB has been being tremendously helpful!

1 Like

depends what @FABerger expects … there is no out of the box feature of openhab to control your (unknown) “basic” thermostat and there are also no standard rules which implement hysteresis & co.

So openHAB is for you if you

  • can write the rules yourself (or ask community for support, or better search for examples)
  • find a proper binding for your hardware

So OH provides a platform for you to “implement the thermostat function in software.” It proves connections to and an abstraction between 200+ different technologies and software APIs that lets you combine and interact with thousands to tens of thousands of devices from hundreds of companies.

There are tons of examples posted to the forum of software (i.e. Rules) that implement behaviors similar to what you are after. However, OH doesn’t just do it for you. You have to put in the work to implement the behavior. Though I will say it isn’t really all that much work and there plenty of people on this forum who are willing to help if you run into trouble.

Everyone’s home automation system is completely unique. It is impossible to “write the thermostat function in software” in a way that can cover every combination of hardware and capabilities one could use to implement this. And even if there were, the current Rules Engine doesn’t really provide a method to distribute and reuse Rules in this way (the new Experimental Rules Engine will allow this).

If you want that and are unwilling to put in the little bit of work necessary to implement it yourself then OH may not be for you. However, I don’t know if there are any other platforms that do not require the same amount of work from you up front. Home Automation is hard and requires a good deal of work on your part up front no matter what hub you are using.


It is!
Point is, just as @rlkoshak stated, openHAB just provides you with the framework to connect to all those technologies and devices. To code the logic is up to you, the user.
Now while for simpler tasks than heating, you may ask for (and find) examples here on the forum, each and every housing/heating installation is pretty unique. I guess that’s why there’s no generic ruleset available and nobody is capable of or willing to share his specific implementation.
While heating is the most basic function from a feature point of view, it’s also the most complex and challenging one to implement. Lighting is much simpler, as are most playful extras,.
My own heating.rules is about 1k lines of codes, and you wouldn’t probably even understand all the logic behind because that’s vastly tailored to meet my housing specific requirements. Most certainly it would not fit your needs or anyone else’s.
But yes, openHAB can do it for you - you just have to start coding yourself.

@FABerger, please take a look at this topic:

I am working to provide a flexible, open source framework of components for climate control using openHAB. I am developing this based on the work I am doing at my house, but want to make it work for as many people as possible so please submit feedback and request features.

The plans for my house:

  • Temperature sensors in every room (I am using 1-Wire DS18B20, but anything that produces a number should work)
  • Software thermostat for every room
  • Servo controlled air dampers for the central air / furnace ducts to each room
  • Ceiling fan control

The software thermostat from the link above does support automatically changing modes which can be used with time of day, calendar, or presence. A different function might need to be added to integrate open window handling so that the thermostat goes back to the previous mode when the window is closed.

1 Like

Magcode wrote:

there is no out of the box feature of openhab to
control your (unknown) “basic” thermostat and there are
also no standard rules which implement hysteresis & co.

I do not want to “control” it - it is after all a simple electromechinc on/off switch that can’t be “contolled” except by moving the desired temperture wheel. I want to replace it.

What is after all the point of using a powerful computer like the PI in the first place, if not to replace all those expensive distributed room units? All I need in the room is a temperature sensor. Everything else can and should be emulated in software. This is the simplest and most basic task I expected openHAB to do. If it isn’t up to even that, then certainly it can’t be for me.

P.S: I messed up my mail setting and for the time being have to resort to the dreaded web interface. Sorry for the delayed reply.

If you are asking whether it is up to the task in terms of performance, features, etc. then the answer is that OpenHAB is more than up to the task - and then some!

If you are asking whether there is a ready made solution that you can simply plug in and start using, then then answer is that there is not - you have to make it yourself (based on examples and help from the community).

If you are not able or willing to do that, then OpenHAB may not be for you.

1 Like

Maybe this gives you an idea what you actually have to do in Openhab.
I’m having an equal (even the same?) challenge in the next months:

I’d like to replace my wall thermostats for floor heating

In order to do this this is my raw plan:

(1) Detach the actuator from the old controller. (I have such devices:

(2) Connect them to a Wifi/LAN enabled Power Switch which can be controlled by openhab
(I’m using,1,4,2,9f801329,0.jpg but also Sonoffs are a good choice)

(3) Make temperature sensor data available in Openhab (I’m using

(4) Now write openhab rules like this:

if tempBathRoom<23 then send "ON" to Power Outlet "bathroom-actuator"

of course (4) can then be extended with timers, configurable target temp, vacation timers etc…


For completeness, your rule using the default rules engine would look like this:

rule "bathroom temp"
    Item tempBathroom changed
    if(tempBathroom.state < 27) {
    else {

All you need is a temperature sensor AND a valve, solenoid, relay, or whatever it is that actually controls the heater that can both integrate with OH.

Which is exactly what OH provides. It connects to tens of thousands of devices like these and let’s you write the software to control them.

That IS home automation in a nutshell.

But like I said, everyone’s home automation solution is unique so it is you who has to write the software part. OH does a ton of work to make that as ready as can be but you still have to define the behavior and write the software to implement that behavior. OH takes care of figuring out how to read that temperature sensor that published using MQTT and sending the wireless signal to that relay that talks ZWave for you.


Just my 2 Cents:

  1. openHAB as any Home Automation should be (and is!) capable of handling a huge bunch of logic to automate tasks, you would normally do manually or you are just too lazy to do every day
  2. Basic and quite frankly dangerous tasks (what happens, if your heating drops below freezing at your skiing holiday?) should be handled by much less fail-safe technology.

That being said, my suggestion would be to use the regulation your heating installateur gave you (if too old, talk to him on updating it) and just include or extend some logic with openHAB.

For example:

  • I also use floor heating, which is controlled by KNX actuators (ventils and regulators)
  • I use solar thermal energy, gas heater and wood-burning stove with water tubes
  • In each room I have room temperature controllers

KNX being reliable (and serverless), I control the heating actuators via them. I wouldn’t dare to dip into the logic of the heating system (solar, gas and wood) my installateur built, so what do I use openHAB for?

I established some scenes (Homeoffice, Holidays, schooldays, …), which are implemented in the room temperature controllers. I don’t want to click through the really dumb UI of the KNX push button sensors, so OH does that for me and sends the scenes in the KNX-bus. That way, the logic of the heating actuators is triggered and they control the floor heating. I do have some additional features as I can use Google Calendar or remote UI to trigger the heating, if we’re on holiday or we’re coming home after school or work.

Beware: no logic (even not openHAB’s) will change the delay of the floor heating!

You may also not have solar thermic or an wood-burning stove to heat up your heating… Other things to have a look into include the insulation of your house, the way you and your family use it and so on and so forth. That being said, I don’t think one “automation logic” equals another’s, which makes it hard to have the software for heating.

Again: Try to use as much functionality of existing technical devices (here: heating system) as possible. They are usually much more superior to any home automation (not only openHAB!) in terms of realibility and safety. I don’t know, how often I would be sitting in a freezing home, if I accidentially changed a rule here or a item there and OH2 would run in ERRORs hours later, if I’m not here to fix it.
So for me, home automation starts, when the technology I use comes to boundaries or I am too lazy to replicate tasks like pressing buttons every morning to start some action. Try always to avoid fatal deadlocks, when your central point of failure (here openHAB2) is offline for whichever reason.


I think that is basically what the replies here say. Whether you want to call it “control” or anything else.
But the point is that you have to implement it yourself, with a sensor and an actuator: DS18B20 and a solenoid valve for instance if you want to do it per room or just a ds18b20 and a relay if you just want to regulate the main unit