Just getting started and wondering if anyone else has succeeded in using OpenEnergyMonitor with Kensa EVO heat pumps?

It seems I can take the pulse output of the built-in Energy meter (Lovato DMED100T1) but there’s no easy way to access all of the temp/pressure/COP diagnostics directly.

Also wondering what’s best OpenEnergyMonitor pi for the job, bearing in mind that most appear to be out of stock on the online store?

OpenEnergyMonitor’s heat pump monitor should in theory work with most heat pumps, if you place temperature probes in the right places and have a heat meter & electricity meter in circuit. I do wonder if the heat pump itself can communicate to a BMS (Building Management System) and present a list of Modbus registers that can be accessed and logged to get some of the info direct from the machine?

Is this heat pump controller online with WiFi access? I wonder if they have any sort of Modbus over IP / Bacnet over IP set up already. Could be worth asking Kensa if a BMS option is available, if you’re so inclined to start reading data out of the machine yourself.

Glyn has been busy doing something similar with his new Samsung ASHP.

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Hi MJ,
Thanks for response.
Disappointingly, Kensa’s reply to my question Do you have any instructions or advice for using Open Energy Monitor with EVO? was, “having a quick look it can use the electricity meter inside the heat pump, and additional heat meter would be required.”
I’ve followed up with questions about accessing the pump’s diagnostic data but no reply yet.

In the meantime, at least I’ve got the pulse output of the energy meter to get started. Also considering buying an SDM100 which may save time and hassle.

Any thoughts on which Emon processor I should purchase?


That’s a really nice display Kensa has.

I would recommend an SDM120 Modbus, having modbus makes the meter much easier to read than pulse output:

To monitor COP (Level 3 monitoring) you will also need to monitor heat delivered, to do this you will need a heat meter, unfortunately heat meters need to be installed inline on the pipe work, so it would require draining down the system and a plumber to fit it.

If you’re not fussed about monitoring COP but just want to get an idea how the system is running then just monitoring electrical input and flow/return temperature will give you a good idea.

See our overview of heat pump monitoring to get an idea of the different levels of HP monitoring: Heat Pump Monitoring - Guide | OpenEnergyMonitor

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Thanks Glyn,
Much appreciated.
I think I’m getting there!
Great article by John Cantor on Heat meter pressure loss which is making me wonder whether I should keep pursuing Kensa to provide data as opposed to putting additional sensors in circuit which would double pressure loss already incurred.

A correctly sized heat meter will add less than 0.5m of pressure drop which is equivalent to about 4W or less of pumping power on an open-loop system or much less if you have a buffer or low loss header with a 2nd pump, it’s quite insignificant.

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Thanks Glyn,

Not sure if I should start a new thread for this question, but I’ve just ordered an OpenEnergyMonitor HP monitoring kit – without heat meters for time being. (Want to avoid plumbing and some other issues).

Instead, I’d like to put a pocket thermometer (or two) into the DHW cylinder. Can you recommend sensors that’d make life easy communicating with the EmonPi HP?

best, David

Yes, these sensors will work with emonpi

You can connect up to 5x sensors to an emonPi via a terminal block breakout: