Guide on heatpump compatability//which heatpump to buy/avoid

Hello there,
as we are searching for a heatpump to replace our gas boilers, one of the criteria I would like to consider when buying a heatpump is, if it is able to interface with my OpenHab instance to optimize the behaviour of the heatpump depending on the massive information available to OpenHab and make operating it easier.
Now it looks quite confusing to me what kind of standard the heatpump should support. The ebus binding was not updated since 3.2 and it looks to me as if newer models of heatpumps do not support Husdata. Does anyone have any insight on this? Maybe even some experience with current heatpumps?
I am a little afraid of having a proprietary system controlling my heatpump as most of them require cloud services to operate and cannot be as smart as a well-configured OpenHab instance.

Thank you for any advice you can provide!

I do not know anything about other brands, but our Stiebel Eltron heatpump supports Modbus when using their gateway (ISG). There are further options to link the heatpump with smart home systems as far as I know.

There even is a binding (or addon) for OH. I did not get it working with my LWZ304 Trend but directly via Modbus binding it’s working properly.

This gives me the chance to easily take room’s temperature into account by reducing the target temperature within the heatpump or increase / decrease ventilation based on actual CO2 value or…

Maybe this might help a bit :slight_smile:

Sorry, if I know nothing on heatpumps ATM (using solarthermic heating).
But, my golden rule for adding new things to my openHAB is as follows:

  1. get the appliance/device you deem best for your need
  2. check, if it uses local API
  3. decide, if it doesn’t use local API, if it is still worth

I’m half looking to replace my gas heater (only around 6.000 m3/a as most the energy comes from solarthermic panels), so if I would search for a heatpump, I would

  1. search for one for my usecase (low temperature heating? or classic convector heaters?) and chose one with a decent operating factor (Jahresarbeitszahl in german) for efficiency
  2. THEN I’d look if it has a local API (e.g. binding or anything for openHAB)
  3. I’d do some comparisons for different vendors and compare technical specs and APIs

I still could work around a not so ideal for openHAB heatpump, if I gave my central heating unit some commands, which directly affect the heatpump. That way my heating installateur integrated my >20 year old gas heater: if my solar heating storage drops below 50°C, the gas heater will provide some heat up until 55°C - otherwise it’s dumb as a rock.

just my 2cent: If a heatpump offers a perfect integration, but is inefficient, it’s not worth my money. If a heatpump is perfectly efficient and I have more effort to integrate it into openHAB - then I’ll chose that one.

As far as my not-so-serious research into that matter is: forget heatpumps with ebus. They’re either outdated - or rely on expensive additional hardware to integrate.


Almost alle heat pumps have a SGready interface (a 2-bit electrical in) that you can use to signal “heat now”. Anything else is a bonus but should not be a criterion in selecting.
Most also can do Modbus or EBus (I’d NEVER ever get a Vaillant!) albeit as @binderth correctly said extra charges for extra HW are insane, and documentation is always bad or none-existing.

The hardest part in getting a hp installed is to find someone do it for you, and do it in the not-too-distant future.
Most HVAC and electrician guys are very … err selective (not using the appropriate word as that would be against forum charta) so insisting on model X will severely limit your options.
I recently ordered mine via Thermondo, they use LG Therma V, there’s a not-yet-ready-for-heatpumps OH binding for it but the guy to run it is quite responsive so I hope it’s gonna become ready for hp use in the next months.

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since a little over a year I have a heat pump from Weishaupt and it offers by default both a modbus interface and the possibility of control via an app, as well as the WEM portal.
In fact, I use these options only to read the data - only the SG-Ready function is switched via openhab (depending on the availability of solar power).
Extra expensive hardware has not been necessary for this, but the documentation of the modbus is not really extensive.
And of course there is no extra binding for this, but with simple scripts it is quickly possible to read and write the data and communicate with openhab.

Why wouldn’t you get a Vaillant?
It seems to me as if they have a pretty solid lineup with good possibilities to interface. Although that alone is not a colossal criterion to decide, it is definitely a bonus point.

Thank you very much for your guide. That is actually kind of the way I am going about it. Right now we are considering Bosch and Vaillant as there are installateurs in our region working with those brands.
You mentioned efficiency as one of the factors when talking about selecting a heatpump. To me, it seems like most reputable brands actually have pretty similar efficiency. From the calculations I have done, I got only minor differences in the operating factor and it seems to me as if the difference in heatpumps will probably not matter as much as the environment they are working in such as good execution of the installation and proper dimension of the heatpump.
What do you think about this and what are your experiences?

I’ve got no experience at all. just did a little research for my use case which is a bit more complicated, as I do have solarthermic collectors and want to replace my gasheater in near future. But my system is based on temperatures >60°C and I’d like to have a chat with my heating installateur about that - but you guessed it - he’s more than busy these days.
But what I did find on my research: Vaillant has no ootb-interface and it’s “Ebus”, which is kinda dead and the additional hardware costs are way overpriced. So I’d like to think, Vaillant heatpumps might be efficient, but if others are as well, I’d go with them as they offer more direct interface - if that’s what you’re going for! As Markus pointed out a simple “contact” to signal “heat now” would be sufficient to let it heat up, if there’s enought PV excess, you want to put into your heating (if you’ve got a layered storage tank, that is)

Nope. They have EBus but that’s undocumented and Vaillant does not support anyone in any way whatsoever getting it connected to anything non-Vaillant.
Typical bad German HVAC vendor habitude yes, but Vaillant imho have the most ugly closed shop policy I know among major vendors.
Yes they also have EEBus but that again isn’t really open either. Until recently you even had to pay for the spec. This in turn is why there’s practically almost no other systems to support it although it’s been available for quite some years now.

I have been thinking of replacing the district heating system at our house with an air to water heat pump from Nibe ( Nibe is very popular in Nordic countries because their heat pumps have been designed for low temperatures. OpenHAB has a binding for Nibe heat pumps but Nibe also has Modbus which is open so with the Modbus binding you can read the Modbus registers.

I have also been in contact with agents for Bosch and Vaillant heat pumps in Finland. Bosch agent told that their systems are closed so there is no easy way to communicate with them. Vaillant agent promised to get back to me but never contacted me. He said that Vaillant is using EBus and as @mstormi said it is not well supported.

So, in my case the choice is Nibe S-series heat pump.

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