Introducing - a public dashboard of heat pump performance

I’m not sure you could do this on Flow temp alone.
The way it does the DHW runs is to slowly ramp the flow from the cold water temp, so say starts at10C all the way upto and past your DWH target. So that could be 70C in my Arotherm.

The way we’ve thought could be best is to have a CT clamp on the DHW pump and if the watts go past say 5W, class this as DHW?

This would work for me as I have a clamp on my Vaillant controller, that drives the DHW pump (connected to my plate exchange)

But some people may not have a separate DHW pump, especially if they only have a coil.

So it’s tough. :man_shrugging:

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Thanks. All this discussion has made me consider if I can set my Boiler & Tank up in a quasi HP manner running it at much lower temperatures. My issue has always been DHW and needing to heat the tank hotter than 55°C to get decent DHW supply. This has been exacerbated by a new boiler that takes an age to reach a good output temperature (more efficient apparently). I think I have worked out the issue (after 10 years!) and how I can resolve it.

I also think I can trigger this boiler to run at different target temperatures as well (TBC) which might improve things further - effectively a heating and DHW cycle! This discussion has not just benefited ASHP users!




I have a temperature sensor on the cylinder flow (& return), I know it’s doing DHW if this is outside normal boundaries.

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I’m probably an outlier (again! :wink:) but the best and least intrusive indicator of whether my system is doing Hot Water or Heating is which of my two heat meters is seeing the flow:

So I reckon we need to support a range of different strategies for deciding whether our system is doing Heating versus Hot Water - and yet we need to unify those in some way so the MyHeatpump app and HeatpumpMonitor can report on CoP values for Heating versus Hot Water across all the systems.

How about a ‘boolean’ Feed that shows 1 for Hot Water mode and 0 for Heating mode - and everyone decides for themselves how best to derive the right value?

Or 1 for Heating, 2 for Hot Water and 0 for Standby?

Would be hard to derive that from historical data though, which is the appeal of using something like a flow temperature threshold…


A CT around the cable supplying power to the 3-port valve would work for all systems, some 3-port valves even have a microswitch in them designed to be used to provide a signal for applications like this. I’m lucky I can read a boolean register via modbus from my Samsung heatpump which informs the position of the 3-port valves, I’ve used this to separate central heating and DWH in the monitoring.

I post the combined figures DHW + CE to so the data is comparable with the other systems on there, since most of them include DHW


Very nice! The new buttons look great. The cost comparison tool is very cool. Would it be possible to colour the cost green if it’s less than gas and red if it’s more than gas? This would make it very clear that most heatpumps on the site are cheaper than mains gas to run.


That does depend on the Unit Price you are paying for either, of course.

@Timbones looking at this,


I am not sure which value that 'Cost per kWh` is referring to. Should it be effective p/kWh (and swap the column with the gas column I’d suggest).

I think what you are trying to demonstrate is that for the measured heat output achieved, it has cost x in Electricity and would have cost y in gas.

Do you take into account the efficiency of the boiler (probably increases gas cost)?

It is an interesting stat.

Yes, this is “Cost per kWh of supplied heat”, compared to (say) 11p/kWh for gas heating.

I’ve assumed that gas powered systems are (at best) 90% efficient; possibly a bit generous but still a fair comparison.


For some reason the sorting by daily cost does not seem to work correctly?
PS this is now looking so cool.


Might be worth looking at making that clearer in the wording or a further explanation at the top.

I’d add that next to your ppu figures at the top.

It is a really good metric for comparison.


@Timbones It’s looking great now!

I do have a digital signal for DHW/Heating, so it could be left to users to find a way to tell the system as suggested by @dMb .

I wonder if you could also add, on the charts page, an option to do an average profile of all systems (possibly being able to select out GSHP/ASHP or some other paprameters that could be thought about - e.g. something on average ambient temperature or degree days) using something like the existing ‘Profile Explorer’ App. From a personal perpective I’m thinking that his could start to get quite useful from a policy/grid reinfrocement perspective when there are a few more systems on board, but it does also provide a way for people to compare their own system with the average in a more granular way. It may be a bit of big ask :slight_smile: , but just thought it might be interesting. This is my ASHP profile… (not got a full Feb or Mar yet)…


A monitoring trial of real-world efficiency of condensing boilers in 60 homes measured an efficiency of 82.5%

It looks like quite a good study with lots of interesting graphs.

Only a few boilers got close to 90% efficiency, I think using 85% as the average efficiency would be closer to real-world:


Thanks Glyn, I might use that. That puts effective cost of a gas system closer to 12p per kWh of heat, meaning more of our heatpumps are “cheaper than gas” if they have a SCOP better than 2.9.


I’d agree with 85% - I was going to quote the same study Glyn posted, but it’s quite old - 2009 - and with recent campaigns to get people to lower flow temperatures averages are likley to have gone up a bit, but 90% seems pretty hard to achieve!



Hi everyone. I’m a product manager at UK not-for-profit Icebreaker One, responsible amongst other things for the Open Net Zero net-zero data index.

We love HeatpumpMonitor and would like to index it but we’re having trouble finding the data behind the visualisations - our aim is to index the data itself to make it more readily available for people analysing it, rather than websites with tables or graphs.

Could someone point me in the right direction please, or tell me it’s not ready for that yet? With my “encouraging good data citizenship” hat on, I’d also recommend you publish a specific licence for people using the data on the site. The Creative Commons or Open Data Commons licences would be a good place to start (can’t link to them due to new user limitations on the forum). Happy to answer any questions about this.


Welcome, Chris, to the OEM forum.

You should be able to now.

Hi Chris,

We’ll need @TrystanLea and @Timbones to comment on the practicality of providing access to the underlying data.

The point about licensing was raised on a recent webinar discussing HeatpumpMonitor with a recognition that including Attribution for bare data is problematic and that a more permissive license might be appropriate - but the key thing is to declare which license applies.

We also discussed whether we would need the individual contributors to opt-in to making the data more widely available, which might need bottoming-out first.

Yes agreed that would be interesting to see. Will try and look at that next time I get a development window on this.

Seems fair to me

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Hello and welcome @chrispointon!

Are you after an API for the tables on or the API’s for the high resolution data used for each individual heat pump e.g as used for creating an individual heat pump dashboard? Emoncms - app view dashboard.

Is your intention to mirror data on your servers? and what level of detail would you be seeking to mirror? e.g 10s data, daily summaries for individual heat pumps, 30 day data table comparison, annual?

Yes we need to sort and be clear on the licence as @dMb mentioned.

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