Is there any interest in a Stiebel Eltron climate platform?

Hi all
I have a Stiebel Eltron heat pump (LWZ504e) and an ISG Web with the Modbus module enabled. This allows an easy integration into Homeassistant. Would there be any interest for a proper support?

I already started to play with it (see link), but it would be quite some work.

I’ll be interested! Getting soon a WPC 05 Cool and Nest will probably not work with it (love the interface in the room) and this was easy getting it to work in HA. So I hope there will be soon something for Stiebel Eltron as well.

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I started to work on it and there is already support for receiving the temperature and configuring the operation mode for my LWZ504e. Currently nothing is done for a WPC.

As soon as I get it testable, I will post how to use it.

Hi! I’m interested, too. I’ve successfully installed your current py-Module and can see my LWZ304 in HomeAssistant - THANK YOU! :wink: At the moment I can see the following attributes:

current_temperature: 21
min_temp: 10
max_temp: 30
temperature: 21
target_temp_step: 0.1
operation_mode: auto
operation_list: auto,idle,Warmwasserbetrieb
filter_alarm: false
friendly_name: LWZ304e
supported_features: 129

…interesting would be to monitor power consumption and recovery of energy by the recuperator and several other things. I think we have the same goal, or? :wink: Right at the moment I couldn’t help you that much because I have to understand how the modbus and your component is working. maybe I can contribute later.

Hi mettbert

Nice to see, that someone is using my work! Currently, I am working to get both components ready, the home-assistant integration for a pull request into HA and the python package pystiebeleltron for a push to

I have to clean everything and then sort out the missing translation, eg. “Warmwasserbetrieb”.

Your LWZ304 should be supported by the pystiebeleltron package. Let me know which modbus registers you are interested in detail, so that I can add the information as an attribute in the first release.

In terms of help… you can certainly help with testing the implementation!

I’m interested in the following registries (english translation included):

Address Name


7 Outside Temperature
8 Current Temperature Heating Circuit 1
9 Desired Temperature Heating Circuit 1
12 Flow Temperature
13 Return Temperature
14 Pressure Heating Circuit
15 Volume Flow Rate
16 Current Temperature Hot Water
17 Desired Temperature Hot Water
18 Current Fan Speed Inlet Air
19 Desired Volume Flow Rate Inlet Air
20 Current Fan Speed Exhaust Air
21 Desired Fan Speed Exhaust Air
22 Current Humidity Exhaust Air

28 Current Temperature Hot Gas
29 Highpressure
30 Low Pressure
31 Compressor Runs


1001 Mode
1002 Desired Room Temperature DAY Heating Circuit 1
1003 Desired Room Temperature NIGHT Heating Circuit 1
1004 Desired Manuel Temperature Heating Circuit 1

1008 Gradient Heating Curve Heating Circuit 1
1009 Root Point Heating Curve Heating Circuit 1

1012 Desired Temperature Hot-Water DAY
1013 Desired Temperature Hot-Water NIGHT
1014 Desired Temperature Hot-Water MANUAL

1018 Ventilation Level DAY
1019 Ventilation Level NIGHT
1020 Ventilation LEVEL PARTY
1021 Ventilation LEVEL MANUAL

2001 System Status
2002 System Errors
2003 System CAN Bus Status


3001 Quantity Heating per Day
3002 Quantity Heating Sum

3004 Quantity Hot Water per Day
3005 Quantity Hot Water Sum

3007 Quantity Auxiliary Heating Sum

3009 Quantity Auxiliary Heating Hot Water Sum

3011 Quantity Heat Recovery Day
3012 Quantity Heat Recovery Sum

3022 Energy Consumption Heating Day
3023 Energy Consumption Heating Sum

3025 Energy Consumption Hot Water Day
3026 Energy Consumption Hot Water Sum

3028 Runtime Compressor Heating

3030 Runtime Compressor Hot Water
3031 Runtime Auxiliary Heating
3032 Runtime Auxiliary Heating Hot Water

…I’m not an expert and translated all the news as good as a I can :wink: If something is ready to test, let me know. Thank you in advance!

That’s a lot! I will see which attributes I can integrate with the first release.

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I am interested in this, without using ISG :-).
Currently, I have a RPi Zero with fhem installed and connected via USB to my THZ504(same model like LWZ504). Reading the data and setting values works fine. Now I am trying to export all values from fhem to any kind(maybe SQLdb), so I can process with HA.

A component which reads the values from USB would also be fine.
Unfortunately, I am not that python programmer, to do myself. But maybe there is a python guy needing and reading this. I would support in any kind! :slight_smile:

are you using my API module to communicate via USB or another component?


nope, I have installed on a separate RPi.
For fhem, there is an existing Stiebel plugin/component. All this was initiated some years ago by the work of Robert Penz who wrote some python things to read and write Stiebel devices.
So, this USB read/write thing is a bit difficult. If you have an ISG, everything is easier :slight_smile:

I ll take a look at your API tomorrow. But I think it is much different from that USB thing.


I have a much older Stiebel Eltron LWZ 303 which is not compatible with ISG Web. Did you have any luck integrating the data from fhem plugin into HA as for me this seems the only feasible option?


unfortunately not. I am using fhem on an extra Pi, exporting all data to mysql. Some values are grabbed from the db by querys into hass, but I am using grafana for monitoring.
Currently, if I want to set any values to the heatpump, I am using the fhem webinterface. But there are not many cases. We ll see if the summer will change the usage.
So monitoring is the main aspect. And for that, the mysql db with grafana is perfect.


Shame. I did consider setting up a fhem server just for monitoring the heat pump, but the learning curve just to get started with fhem seems very high.What is your experience? Do you use fhem for anything else or just for monitoring your heat pump?

Hi everybody!

I would very much like to integrate my Stiebel Eltron Heat pump WPC 10 into home assistant.

I do have Home assistant (hassio) running on a pi.

I also do have the Stiebel Eltron ISP with modbus running.

I do have access via web portal and I am also getting some hex numbers by reading out the modbus registers 500 with a windows client software.

But I am struggling getting the pi reading out the modbus registers.

As a first start I just tried to read out via the modbus platform integrated in home assistant.

My configuration.yaml:

  type: tcp
  port: 502
  timeout: 30
  delay_between_queries: 30

My sensors (placed in separate modbus.yaml file):

I tried to “play” with different parameters to check which might work:

- platform: modbus
  scan_interval: 20
    - name: isttem501
      unit_of_measurement: °C
      slave: 1
      register: 501
      count: 1
      precision: 1
      scale: 0.1
    - name: isttem502
      unit_of_measurement: °C
      slave: 1
      register: 502
      count: 1
#      precision: 1
      scale: 0.1
    - name: isttem503
      unit_of_measurement: °C
      slave: 1
      register: 503
      count: 2
#      precision: 1
      scale: 0.1

    - name: Laufzeit535
      unit_of_measurement: h
      slave: 1
      register: 535
      count: 1
    - name: Laufzeit536
      unit_of_measurement: h
      slave: 1
      register: 536
      count: 1
      data_typ: float

But the pi can’t read any values:

No response from modbus slave 1, register 503
11:34 PM components/sensor/ (ERROR)
No response from modbus slave 1, register 503
11:33 PM components/sensor/ (ERROR)
No response from modbus slave 1, register 503
11:33 PM components/sensor/ (ERROR)
Modbus read failed
11:33 PM custom_components/climate/ (WARNING)
No response from modbus slave 1, register 503
11:33 PM components/sensor/ (ERROR)

2019-02-21 08:52:32 WARNING (MainThread) [homeassistant.loader] You are using a custom component for climate.stiebel_eltron which has not been tested by Home Assistant. This component might cause stability problems, be sure to disable it if you do experience issues with Home Assistant.
2019-02-21 08:53:27 WARNING (SyncWorker_18) [custom_components.climate.stiebel_eltron] Modbus read failed
2019-02-21 08:53:28 ERROR (SyncWorker_1) [homeassistant.components.sensor.modbus] No response from modbus slave 1, register 501
2019-02-21 08:53:28 ERROR (SyncWorker_12) [homeassistant.components.sensor.modbus] No response from modbus slave 1, register 535
2019-02-21 08:53:28 ERROR (SyncWorker_15) [homeassistant.components.sensor.modbus] No response from modbus slave 1, register 536
2019-02-21 08:53:28 ERROR (SyncWorker_9) [homeassistant.components.sensor.modbus] No response from modbus slave 1, register 502
2019-02-21 08:53:28 ERROR (SyncWorker_17) [homeassistant.components.sensor.modbus] No response from modbus slave 1, register 503
2019-02-21 08:53:28 ERROR (MainThread) [aiohttp.server] Error handling request
Traceback (most recent call last):

I managed to load but I am subsequently getting no values.

Just the sensor does show up:

climate.wpc10 Notbetrieb
current_temperature: 0
min_temp: 10
max_temp: 30
temperature: 0
target_temp_step: 0.1
operation_mode: Notbetrieb
operation_list: auto,idle,Warmwasserbetrieb
filter_alarm: false
friendly_name: wpc10
supported_features: 129

Up to now I did not manage to load because of its dependancies (hassio did not install by the script; I need to do it manually but need to figure out how).

So long story.

Does anybody has a hint how I should proceed from here. There seems to be a very basic problem.




absolutely not :-).
I love hass and have everything I need integrated. I also love python, so there is no way to use more of fhem, but the heatpump monitoring.
Fhem is a great peace of software, but for me, ui and config style is a little oldschool :wink:


Perhaps a slightly presumptuous question, but would you be able to guide me to get the heat pump monitoring working on fhem? I have read through the Robert Penz article and I have see that there are whole host of guides and forum entries on fhem

@Swiss, @selfisch Would you mind moving the fhem discussion to another forum?

@fregatte You are actually on the right track. However, the modbus registers of the “WMP3i Regler”, which your WPC10 has integrated, are not yet supported by pystiebeleltron. I am working on getting initial support merged into HA for Stiebel Eltron (see HA PR 21199). As soon as that is completed, I can start extending it further and add support for the WMP3i as well. I certainly will need help from someone who is able to test the communication after implementation.

I have a LWZ304 and an ISG Web. I don’t know if this will work with the Modbus but if it does I can help testing.
I really like the opportunity to integrate the LWZ into HA


thank you very much for coming back to my configuration and for pointing me in the right direction.

I would very much like to test (and to use) your stielel_eltron integration with my WPC 10 and will patiently wait for the first release.

Up to now I managed to read some values with the normal modbus platform but I am struggling to write (temperature and operation mode) via modbus.

I think this is impossible without your specific pyton interface.

I will monitor this tread to see when the first release is finished.

It would be great to have everything in one pyton module (if possible) as it is another obstacle to get dependencies ( integrated in hassio.



@azrael783, @mettbert
Finally, the initial support for STIEBEL ELTRON heat pumps has been merged HA PR 21199 and should be part of the next release! It is currently ONLY a support for the heating module and not for the domestic hot water (Boiler) or the ventilation (Komfortlüftung) modules. My plans are to add the domestic hot water module as a water_heater HA platform. And then extend support for the WPC devices.

It would be nice to get some success feedback, so that I can extend the list of tested devices in the documentation! And some feedback from Tecalor users as well.