emonHP Level 3 Heat Pump Monitoring Bundle being installed

We are looking to have a 5kW Arotherm+ too.
The installer has quoted for supplying and installing “Open Energy Monitor heat pump monitoring”. I will ask them for more detail but I am presuming that would include the Level 3 Heat Pump. Am I correct in thinking that bundle connects to home broadband router and uploads the data to the cloud service? If I wanted to capture the data locally (to integrate with Home Assistant) would I also need the Pi hardware/software?

I understand there’s a Vaillant integration for Home Assistant that connects to Vaillant’s cloud service. Is it possible to use that and still share the data with HeatPumpMonitor dot org without the Level 3 Pump Monitoring Bundle?

I like the idea of monitoring the electricity consumption, heat output and (S)CoP locally though, to avoid the cloud/broadband dependency, so would appreciate any insight anyone with a Vaillant Arotherm+ and Home Assistant is able to share, please.

@wzorektom If you do still need assistance with the install, Alex from Libtech (based in Herts) has installed a number of Vaillant ASHPs that publish to HeatPumpMonitor.org.

Hi Welcome, it is usually best to start a new thread or a linked topic :slight_smile:

I would have thought the HP Bundle could connect to both a local instance and the cloud (emoncms.org) instance but I don’t know.

If it can connect to both, then you just need a Pi and this is the simplest route (any model even a PiZero would do) or else it could be installed in a virtual environment. There is also a HomeAssistant addon in the wings.

@glyn.hudson or @TrystanLea are best placed to answer more.

The OEM HP monitoring is more accuracte AIUI than the ASHPs own data. You probably can use HA (I’m not sure anyone has done it yet), but you seem to want to avoid cloud services as a preference and using Valliant cloud service goes against that :slight_smile:. If it was me, I’d install the HP Bundle and also capture the data locally. :smiley:

Thank you for the info and splitting the topic, apologies.

After posting I found the Emoncms History - Home Assistant (home-assistant.io) integration which sounds like it could be an option for passing the data extracted by the myVaillant software up to emoncms dot org.

My dislike of cloud services is more related to devices that don’t have a local store, which then do not catch up when an issue with the cloud service or connectivity is restored.

But if the OEM HP monitoring (and I presume you mean Open Energy Monitor, rather than Original Equipment Manufacturer - Vailliant) offers higher accuracy then that’s definitely something I would still consider.

A Home Assistant add-on that potentially captured the data locally from the heat pump monitoring hardware and also synchornised the data to emoncms/heatpumpmonitor would be awesome as it sounds like that might save running an additional Pi.

I am running Mosquito Broker and GivTCP (for GivEnergy HACS integration) and not really familiar with how MQTT works. Can Home Assistant handle/monitor multiple data sources on MQTT in the same way it can connect to multiple devices via Bluetooth and/or Zigbee?

Well this is the OEM forum :rofl:

I agree - see this thread Emoncms self contained docker container and HomeAssistant Addon but definitely Beta ATM.

I’m not sure how the Valliant system works or if it catches up. I’m not sure the emonHP catches up either.

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Hi Richard,

I’ve done plenty of comparisons between different ways of pulling data from my Arotherm this past year.

The Home Assistant Vaillant integration doesn’t provide anything above what you can pull from the myVaillant app. (it just scrapes the same data).

The myVaillant app (and so the HA integration) is notoriously optimistic when it comes to COP etc compared to a heat meter setup. Can’t really be trusted imho.

I’ve been playing with eBUS adapter too. Pulling data directly off the BUS connection of the heat pump.

This is better data, but things like electric in and heat out don’t seem 100% accurate at the moment and are slow to come through. I need to do more digging on this.

Bottom line, if you want accurate data, get the Level 3 heat meter package.
You can send that data over to Home Assistant if you want too.
And yes, it can be local only if you want.

But we’d really like to see your long term data on https://heatpumpmonitor.org/
Especially me, I wanna see more 5kW Arotherms. :joy:

Thank you. Really appreciate the insight.

My ASHP installer has quoted £720 (possibly plus VAT) for the OEM heat pump monitoring and mentioned that one of his customers may be willing to share their insight in integrating that with Home Assistant.

Don’t feel obliged to answer but, did you opt for the extended warranty on your Arotherm? £200 to extend from 5 to 7 years.

EDIT: And… is it worth me running two ethernet cables to the ASHP install location for the myVaillant hub and OEM metering to avoid connecting them via WiFi?

It’s dead easy to integrate emoncms into HA.

You can select some or all of the feeds in emoncms to pop up as entities in HA.

tbh, I didn’t even know this was a thing. So, no! LOL.

Absolutely. If you have the chance to do that now, I always prefer cables over wifi.

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Yes if you can. Always better.


The emonHP includes a RaspberryPi which reads data from the Heat Meter and Electrcity Meter and posts the data to https://emoncms.org. You can also log the data locally to Emoncms running locally on the emonHP. The data is also available locally via MQTT.

Yes, the OEM system is totally separate to Vaillant and won’t affect the Vaillatn system.

You can use the Home Assistant Emoncms integration to get data from the emonHP into Home Assistant, this can be done via local network: Emoncms - Home Assistant

To be able to share data with heatpumpmonitor.org it’s easiest if you use our remote server https://emoncms.org, but it’s possible to share data from your own hosted server, but it would need to be publicly accessible. 10 years+ of free https://emoncms.org usage is included with the bundle.


Yes, but no need to run two cables. A single cable and a network switch will also work fine to connect two wired Ethernet devices. Using wired Ethernet is definitely a good idea.

Thank you. One for the Vaillant VR921 and one for the emonHP?

In this instance I would prefer to run two cables from an existing switch than run a single cable and add another switch.

A single Cat5 can carry two network connections, using appropriate splitters at both ends…

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That’s good to know, I didn’t think this was possible without a switch. Looks like this would be a suitable adaptor?: https://www.amazon.co.uk/TNP-Ethernet-Combiner-Splitter-Surveillance-MMF-MFF/

Might be worth adding that to the Shop page and also adding the emonHP to the Docs :slight_smile:

@LeiChat - to be clear, what happens is you send the same data to 2 separate instances of emoncms; one local and one remote. It is not a sync between the 2 so you may, over time, get some small differences. It also means you can record more data locally than you do remotely. Finally, if your internet connection does go down, there is a limited amount of ‘catchup’ when it gets restored.

Yes, not many folk do, but I have done this in a commercial environment. Slight chance of interference between the 2, but very rare with good quality cable.

Single cable per connection is always preferable though.

Though there is also a sync module that lets you send data from the local to the remote instance, keeping the data identical and coping with outages.

Yes, but AIUI this is a one shot, not a live, routine sync. Again AIUI, because the 2 servers time will not be in sync, there is a risk to the data integrity if you try and ‘fill in’ missed data.

Ideally, you would store in one place and send an exact copy (including timestamp) on automatically, but emoncms doesn’t do that.

Have you successfully used the sync module to fill in data?

Is the emonHP capturing the data and then sending it to one or more emoncms APIs or does the data capture process work independently for each targeted instance of emoncms? Asking with respect of the ‘small differences’ or is that just due to potentially lost request/response.

For my install, if I am running one cable, I might as well run two. Fortunately have a few ports spare on the switch. I am more worried about the power. Is there a PoE version of the emonHP in the works? :wink:

The ‘data capture’ is done by the emonhub part of the system - it reads the different interfaces that have data on them.

It (emonhub) can then send the data to as many different end points as you want and different data sources to different end points.

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Mm looks like you need to choose a splitter carefully, probably easier to use a switch, they are pretty cheap these days:

The emonHP reads the data from the heat and electricity meters and then can log the data locally and then optionally post to a remote emoncms server. There shouldn’t any differences between logging local or remote since we’re reading the kWh figures from the meter directly rather than calculating them.

No, but it’s no problem to extend the mbus and mbus cables, so you can locate the emonHP in a location where you can get power.


Cross posting from a thread about the myVAILLANT integration on the Home Assistant Community Forums as I thought it was interesting. The delays in the Vaillant API upload/download sound a little frustrating.

myVAILLANT integration - Third party integrations - Home Assistant Community (home-assistant.io)

emonHP FTW!! How’s that HA integration coming along? :wink:

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