New Daikin Altherma 3 Installation - Monitoring


This is my first post here, so hello.

I have a Daikin Altherma 3 installed by Octopus Energy around 3 weeks ago. The model number is EDLA09D3V3.

The installation went really well and they have done a really good job, it’s very tidy and I am happy.

Apart from on the day of commissioning we have not used the heating for obvious reasons but the hot water is working well and we are so pleased to have got rid of what we had before.

There is one part of the system that I am not so thrilled with and that is the information available regarding efficiency.

We are using the Daikin MMI and a Madoka thermostat and it’s all really good apart from the data on energy consumed and heat produced.

I dare say this will be a common and popular setup given the number of installations that Octopus are carrying out and I would guess that other people would like access to better data than you get as standard.

I want to do something about this before the winter comes.

I can see that I have three options.

First would be to stick with what I have.

Second would be to access the data from the heat pump via one of its serial ports and do something with it in Home Assistant.

Third is to buy and have the Openenergy monitoring system fitted.

I favor the third option as I believe it would give me the most accurate results.

I understand that Octopus have fitted the Openenergy system to some installations and I wish that they had offered me the option of this at the planning stage, it would have been really easy to install at the same time.

My only real concern about fitting the system is finding somebody to do it that understands what is required and the only way I can give myself the best chance of it not going wrong is to make sure I know what is required.

I think I understand where everything will go and I have some photos of the installation that I can post if it will help.

I would be interested to know what anybody in a similar situation has done, particularly owners of the same heat pump.

Thanks in advance for any replies.


Here are some pictures of the installation.

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I am totally confused.

I am an accountant, I am not thick but all of this is beyond me I have to admit.

All I want to know is how well my heat pump is performing, I just want to know its COP.

I have looked at ESPaltherma.

I can buy the hardware with no problem.

My heat pump knows its leaving water temperature, its returning water temperature, its flow rate and how much electricity it has consumed. Surely that is all I need to know to work out the COP?

But then I need Home Assistant.

I have watched videos about Home Assistant and just don’t get it.

I have a computer and a smart phone. Do I need more stuff?

I am vaguely familiar with virtual machines, we have it at work. Why do I need one for Home Assistant?

Why can’t I just install Home Assistant on my computer and use it?

I really don’t understand any of this.

Can anybody help me?

I had a post installation visit from an Octopus installer today.

It’s a routine check up to make sure everything is working properly and a quality check on the installation.

We discussed the openenrgy monitor and it is looking hopeful that Octopus will be able to install it for me.

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Hello @matt-drummer great to hear that you have an Octopus Daikin installation. If they are able to install the monitoring system for you, that will certainly be easiest. Once the system is installed please email us and we can arrange access to the data.

Alternatively if they are unable to install the monitoring system, I did install this P1P2 interface device on my father in laws Daikin which pulls out quite a bit of useful information I cant remember now what the Daikin gives as performance feedback on it’s own controller display?


Thank you.

I sent you an email yesterday to the address on your website, have you read it?

I am going to install your system one way or another.

I just don’t know whether Octopus will want to source from you themselves or not.

I will let you know in due course.

Thanks @matt-drummer seen your email now, @glyn.hudson will get back to you about this soon Im sure and if we hear from Octopus relating to your system. Cheers!

Interesting to hear that Octopus have installed a Daikin Altherma 3 for you.

This is because in 2022 Octopus bought Renewable Energy Devices (RED) a manufacturer of ASHP and Octopus are using them to make their own in house products for supplying to and fitting for their customers.

It could be they are offering the Daikin Altherma 3 to customers with older properties needing a higher temperature system.

However, based on this, do you know if Octopus are able to install any other brands - e.g. Samsung?

I don’t think they supply anything but Daikin at the moment.

You could ask them.

I don’t think the Altherma 3 is any more suited to properties requiring higher flow temperatures.

Mine is no a high temperature system, it’s a standard low temperature monbloc.

Hi Matt,

Not sure if you solved this.

You can go in to the MMI controller and go into information which gives all of the energy data.
Daily, Weekly, Monthly and Annualy, from memory it will have total sum of input, output, heating and hot water.
The COP/SCOP would be a division of the figures, it doesn’t give you an actual COP number on screen.

Equally, if you have the Onecta app installed with the wireless “SD card” part code BRP069A78 you can view energy data on your mobile device however I think it gives similar data to that on the MMI…


Hi Ant,

Thank you for your reply.

Yes, I have all of that and can see all the information you describe.

I am sure, for most people, it will be enough information.

But it is limited, it’s not very granular, I think that is the word, basically it only reports in whole kWh.

I have fitted a ct clamp monitor on the power supply to the heat pump and I can now see what it actually uses which is useful.

The MMI and the app actually report daily usage as 1.0 kWh but it never actually uses the decimal point.

I know the information is in the heat pump and available to be extracted and I am part way through setting up espaltherma but had some problems with sandisk usb drives before I went on holiday and I was waiting for my M5StickC to arrive.

I now have all of this and some different usb memory sticks so will have another go.

Ideally I would like Octopus to fit the Openenergy system for me but I am still waiting for a reply from them on this.

I know it’s all a bit unnecessary but having come so far will my solar panels and battery storage I would like to complete the job, if you know what I mean.


Right im with you, it is pretty limited in information at the moment.

If you have Madoka and solar PV it might be worth doing some research on their HEMS system, (I think its Daikin HEMS), it ties in the solar PV and heat pump into the Onecta App.

I dont think it gives you the indepth information you require but it does tie everything together so you can do hot water and room buffering (so I am led to believe) and gives you information on what energy is going where and when (not sure if battery is included or in development)

I’m not sure what stage they are at with the UK but I have seen that it may be available now or any time now.


Hi Ant,

Thank you for the information, it’s very helpful, I will have a look.

I am really happy with my Givenergy system, it works really well. I have four solar arrays, one with Enphase micro inverters and the other three have Growatt inverters and Tigo optimisers on every panel, mainly so I can see what is going on with each panel, I have some but minimal shading issues.

I have 13.3 kw of solar panels and generate around 12,000 kWh per annum and I have 38 kwh of usable battery storage.

I already have enough in my Octopus account to pay for the winter electricity use and will build more before the winter comes.

Leaving aside my capital costs I pay nothing each year for energy, I actually have a small income from it.

I would like to document my system and ideas in some way, maybe with a youtube channel. I don’t want it to be as in depth as some people go but I feel I need more than I currently have in terms of what the heat pump costs to run and its efficiency.

We moved to this house 2 years ago and it had some panels and I have added to it extensively and I feel compelled to share with people what is possible.

I’m no genius but I am quite proud of what we have achieved this year and my story might help and inspire others to do something similar.

I think that reducing our reliance on fossil fuels is a good thing and we need more positive stories around heat pumps and electric vehicles. there is a lot of negativity coming from people with no actual experience of this technology, basically people perpetuating untruths with no relevant evidence to back it up.



Hi Matt

Very interesting set of posts! I’ve also had exactly the same gear installed by Octopus, in May, and lots of K2/K3 rads to keep the flow temp low :-). I also contacted them about a post-install of more effective monitoring gear, but was told they don’t do that. Obviously, if you here otherwise, I’d like know. I’m loath to modify anything at this point because of the workmanship warranty, but I am acquiring some Tuya-based CT clamp energy monitors for the total and HP-specific energy usage. I equally find the Daikin app data ridiculously coarse and low value - it’s more to reassure you that something is actually happening, I suspect!

I’m about to start on a solar install to go with it, 14 panels, Givenergy inverter and 9.5kWh battery, which will considerably reduce our use of grid and/or bills, with opportunity to load up overnight in the winter. That’s quite a battery setup you have there!

I also messed about with Home Assistant, fun but ultimately frustrating, the only advantage is that it has a Daikin cloud interface which allows you to store and recall the time-based data from the controller more effectively. I haven’t been running it recently, but will re-investigate hopefully before winter.

Cheers, thanks for the input

Hi John,

Firstly, thanks for posting.

I hope we can both update our experience as we go through our first winter and compare as much as we can.

Octopus did come back to me about a month ago to inform me that it wasn’t possible to to fit the open energy monitor free of charge.

I thought it was quite strange that they thought I wanted them to install it with no charge!

They did say that they were going to look at fitting it for me but so far I have heard nothing more.

I don’t feel there is any benefit in chasing them over this but I am determined to have the system so I placed my order for the monitoring system yesterday.

I had my solar panel installers here this week to add something to my panel monitoring and the electrician who I trust will do the electrical work for me.

I know how to do it myself but I just feel more comfortable with a professional doing the work. I will assist him and make sure I understand what we do and get it done how I want. It helps that I know his work and have complete faith in him.

The plumbing is quite straightforward and I know I can drain the system and do this myself. The only part I don’t feel confident about is refilling the water and purging air from the system.

I have a plan though and I’ll let you know if it is successful.

My panels and batteries seem over the top at first glance but it has really worked well so far, my exports since April have generated me £1,200 so far net of any small imports, enough to get me through the winter.

I am still on Flux and expect to be so for another four to six weeks, I am still exporting over 30 kWh a day at the moment on average.

I will switch back to Economy 7 at some point. I am hoping that Givenergy will come out with their EMS soon so I can add another ac charger meaning I can get through the winter on only night time electricity imports.

I have fitted a ct clamp monitor to my heat pump feed so I can see the actual energy use. We are using around 650 watts a day to heat our tank and about 4 kWh for the weekly legionella cycle.

We used 43.96 kWh in August and my Daikin app reports 44 kWh.

I also now know that the Daikin heat pump consumes around 15 watts an hour on standby.

I also have all I need to install Home Assistant and monitor the heat pumps internal data. I also found Home assistant difficult and had problems with my Sandisk usb memory sticks getting corrupted. I have some new memory sticks that I bought whilst on holiday and will have another go when I feel up to it!

I’ll update this more as time goes on



Note-comparing - yes indeed.

Usage - MMI says 4kWh for legionella, 1kWh for daily water, so I guess it’s just decimal points - not much individually but loads over a year!

I’m still on Octopus basic, haven’t plucked up the courage to go for a “costly cooking” rate, at least not without some sort of offsetting mechanism. We could of course change our habits, which we probably will with that impetus. My plan is to go for Flux or whichever works out most cost effective - the JFDI part of me says “Agile”, because of the upside, in combination with a better export rate.

I installed HA on a RPi I had handy, so after an abortive “raw” install, I went for the Docker approach and it all worked fine. My only problem was getting data out of it, because it only keeps 10 days of history and thus it’s rather useless for longer term monitoring, but I found an API and wrote some Python to extract data and stick it in a SQLite database for the time being.

In respect of drain/refill, you should have some auto air venting at the top of your system, I don’t think the installers did anything special to make that work. They had to come back to install a mis-sized radiator that just had inline valves to isolate it, and also do some heavyweight power flushing, and they just filled it up and it’s been fine, as far as I could see. Do it now, and you have time to get a plumber in! I suspect their installers are pretty busy installing, and snag fixing, so don’t have time to do “off-topic” modifications like yours.


I have isolator valves on the flow and return to the heat pump.

I really only have to concern myself with the heat pump filling up again, maybe a bit simplistic but I don’t think it is too difficult.

I just don’t want to mess it up as it is our hot water and heating.

I am quite handy at this sort of thing, I have plumbed heating systems and wired houses before, but I am an accountant, a bit older and a bit lazy with just enough money to be able to pay somebody else to do it!

I have a small computer from work that is almost new that I can run HA on, I just had problems with Sandisk usb drives that kept getting corrupted with no way to fix.

I still haven’t fully decided on which tariff to go for over the winter but I know I want to be on Flux for as long as possible.

I added lots of panels this year and I am guessing as to their performance over the winter. So far they are doing better than I expected, I hope I can get well into November before I need to change, we’ll see.

How are you going to run your heating?

I plan to use pure weather compensation.

If I have our radiator sizing correct then I will be able to just leave all my trvs wide open.

My only concern is that the radiators in the bedrooms my not be enough, I am sure they are but they are the ones I will change if necessary.

If I need to change I will take some K2s from downstairs and move them upstairs and then fit K3s downstairs so I can reduce my flow temperature.

I may do that next spring in any case but I need to see how the winter goes with what we have.

I am more concerned at making this as efficient as I can than saving money, its become a bit of a challenge/hobby.

I am convinced that heating zones and trvs will hurt the efficiency, my aim is to balance the flow temperature to the heat loss of the house according to the outside temperature.

I just want the water to flow for as long as possible at the lowest flow temperature to keep us warm.

I am confident that we won’t be cold, I do know that the heat pump and radiators we have are enough to keep us as warm as we would ever want, that is 20c or more.

I didn’t do this to sit in the cold just to save money :slight_smile:

We moved to this house 2 years ago and it had 4 kWp of panels installed in 2014.

For the first eighteen months we did organise ourselves around the solar generation to some extent.

Our setup now with 13.6 kWp of panels and 38 kWH of usable battery storage means that is less of an issue.

Now we don’t really have to think about it at all.

Even if we import electricity at times I don’t really care as if we pull it from the grid and it doesn’t go into our batteries then we just have more to export later the same day or the next day.

As long as the export payment is close to the import rate it doesn’t matter. I know there are charging losses but as long as it’s close it’s an an amount I am happy to live with for our convenience and lifestyle.

In the last seven months we have imported 10 to 15 kWh per month.

Our system is designed to make life comfortable and efficient and is centred around the heat pumps needs in the winter…

That all makes sense. What batteries are you using for that cracking storage setup?

I have four Givenergy Gen2 9.5 KWh batteries.

I did two bouts of additional panel installation adding two batteries each time, it meant I paid no VAT on the battery installation, a considerable saving.

I would have done it in one go but wasn’t sure how well the panels would work on my north east facing roof so I did it a bit at a time.

I actually added some on my south east facing garage first, I already had some but the new one have more shading issues from the house.

Then I added the whole roof on the back of the house facing north east.

Then I got greedy and filled up the back of the garage!

My original FIT system produces 4 mWh a year and I expect the new panels to add 7 to 8 mWh a year.

Our house consumes about 3 mWh a year and I expect the heat pump to consume another 3.5 mWh.

We should end up with a net export of 4.5 to 5.5 mWh a year

With our FIT payments that is a net income of around £2,000 a year and I pay nothing for energy.

It is worth £4,000 a year to us and so we get our money back for the capital cost in seven to eight years.

We are not too heavy on the batteries for most of the year, I’m not sure how long they will last but it will be more than ten years as they are guaranteed. We may lose some capacity of course.

The panels will last much longer although the inverters won’t but they are also guaranteed for ten years.

I don’t think we can lose unless energy prices seriously fall which I can’t see happening in the medium to long term.

But again, this was never about money, it has always been about me feeling good about what we have done and not burning anything.

I am no eco warrior or anything like that, this just makes me happy that I have done all I can not to pollute our local area.