@carlo - welcome to the forum. 

I don't know about LG, but my Midea heat pump and many other brands collect and report raw heat output data ie flow rate, leaving water temp (LWT) and returning water temp (RWT) which gives delta t and with the circulating fluid specific heat can be used to calculate the heat output. You may already be doing that, but if not, it might be worth a try. 

I appreciate you want an independent of data, but the kit needed is not, as you say cheap, and it is necessarily invasive. As it happens I had an analogue flow meter added by my installer at installation time on the radiator circuit, and I use that to crudely verify the the Midea flow rate figures, which are pretty similar. I also rather crudely verify the delta t with an infra red thermometer on the flow and return pipework, and again the Midea figures aren't that far out. So far, I have taken the view the Midea data is 'good enough'.

A couple of other points. If you are calculating a COP, then you must also be collecting energy in. Are you confident that side of things is accurate? The other is that these things are much easier to do when it is cold outside and the heating is on. I can't help wondering whether your low COP is somehow related to operating a heat pump in warm weather - I presume it is warm in Italy! Or perhaps you up at a very high altitude where it is cold!

More details about your system might help us give better answers.

And a final thought - in a way, LG generated data is the ideal data with which to approach your installer. They have to believe it (they installed it!) - or else they have to go through some compromising routine of saying yes we did install it, but we don't believe it.   

I installed the heat pump in December '24, so the data is from last winter. Right now, and since march, it is only making DHW.

I want to be ready to better measure this coming winter.

These two pictures from the Heat Pump panel show the "potenza", power, which is the electrical energy consumed, and "energia generata", energy generated, which is the heat output.

The pictures where taken the sixth of January, and by doing a division report a COP of about 1.6.

Dividing by the five preceding days it gives me about 2kw continuous, which seems to me a little low and way less than the 14kw machine that was installed.

Water output was set at 40° and later in the winter even lowered to 37° without appreciable differences.

The system is also not well installed, the workmanship is nice, but the design leaves a lot to be desired.

For example I have a 100l buffer tank on the return of the heating system, but they also put it on the return of the DHW tank.

So now when I heat the DHW I also heat 100 more liters of the buffer tank.

@carlo - Do you have any more recent readings, even the current ones. Just a few days in mid winter immediately after installation isn't much to go on.

You will already know this I suspect, but worth emphasing that buffer isn't doing you any favours - if it is a buffer rather than a volumiser. The way you describe it suggests it may be the latter? 

@cathoderay The buffer got lost in translation, it is a volumizer. In Italian it is referred to as "puffer" for some reason or "volano termico", thermal flywheel.

The output of the heat pump is connected directly to the heating system.

These are some more measurements taken the second of February:

Electrical energy consumed. The lines are day, month, year. The columns are heating, cooling, DHW, total:

Thermal energy produced:

For that week I have the power profile of the heat pump, at this point the outgoing water temperature was set to 37°:

The 6kw peaks are the DHW cycles. After the cycle it goes to zero because the volumizer is installed on the return of the DHW.

So when it makes DHW the volumizer also gets to 50°, which is higher than the 37° requested of the system.

The outside temperature:

And the internal temperature:

I will add a bit more information, but at this point maybe it would be best to open a dedicated topic:

The house is about 190m2, on two levels, one of which is the basement. I have another apartment on top of me.

Windows are double panes with aluminium frames.

Walls are about 30-40cm thick, made of two hollow brick walls with a cavity between them, with a flimsy sheet of paper backed mineral wool in that space.

The basement floor has no insulation. The basement walls are made with one layer of hollow bricks and then there is a 1m cavity separating them from the reinforced concrete retaining walls.

The heating system is made of aluminium radiators connected with 12mm pipes. I don't remember the diameter of the big feeding pipes but I think it was on the order of 30mm.

These are the new version of my radiators, not the same but very close:

Radiatori per il riscaldamento domestico - Sira Industrie

I have in total 98 elements of the 600mm sized ones.

I hope I have included enough information.

Posted by: @carlo

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The buffer got lost in translation

But Italian is still a beautiful language!

I agree that over the longer (but still not very long) period the COP appears to be less than 2, which is not good. 

If I were in your position, I would start by looking into (a) how LG derive the energy in and out figures including what they actually represent because at least one manufacturer's (Grant?) energy out data is not the total energy out but the extra energy produced over and above what is put in, thus COP = (energy in + extra energy out) / energy in and (b) is there any data I already have, or can easily collect, that can verify the LG reported figures. Does the heat pump have its own dedicated supply, and if so, does that have any metering on it? 

Posted by: @cathoderay

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at least one manufacturer's (Grant?) energy out data is not the total energy out but the extra energy produced over and above what is put in, thus COP = (energy in + extra energy out) / energy in and (b) 

Same with Vaillant btw

Posted by: @jamespa

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Same with Vaillant btw

Thanks. It may be just Vaillant, not Grant, I just had a vague recollection that not all manufacturers present their data in the same way, but couldn't track down which one I had come across. The question for @carlo is what do LG do?

@cathoderay I had the same thought about the "energy produced" pane, but the LG documentation is extremely lacking on explanations:

The bottom part, the ones related to the energy statistics, roughly says:

"information include instantaneous power and the use of energy/calories up to the annual tendency"

Which means nothing. If the phrase sounds broken is because it is also broken in Italian.

Besides, if it were actually the extra thermal energy produced, the COP would go from 1.6, unacceptable, to 2.6, not particularly good.

With 40° of water temperature and 2-7° outside one LG advertises between 4.05 and 4.5.

To get to 2.6 the outside temperature needs to be -15.

1.6 isn't anywhere on the table.

I know the advertised ones are not necessarily real, but still...

One of the LG technicians that came to see the system said that I was making the right calculations, but I really don't trust them to know. (for reference: other LG technicians, the ones who came to do the first start of the machine said that I should set it at 55° because I have radiators with the thermostat to turn it off when the house reaches temperature. So sometimes it is off and I save money)

For the electrical consumption I have a shelly installed that confirms, with single digit difference, the numbers on the panel.

For the thermal output I would like to install something on the heat pump, hence this very topic.

I did try to make some power output calculations based on my radiators, by knowing the in and out temperature and the room temperature. Considering 20° inside, 37° output and 34° input my radiators give about 2.8KW, but I don't know if it is accurate enough to reach any conclusion.

Posted by: @carlo

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Besides, if it were actually the extra thermal energy produced, the COP would go from 1.6, unacceptable, to 2.6, not particularly good.

As you say its poor either way.  I have tried to find out how they calculate it from the manual (which is pretty poor) but cannot.  I will keep trying!

If you would like some suggestions can you start a new thread and post some information about your system:

• House calculated heat loss and design OAT
• House area and construction
• Model of heat pump
• Buffer/no buffer, any other system separation (low loss header/plate heat exchanger)
• volumiser/no volumiser, where plumbed (flow/return)
• type of emitters, any detail about them you can give us
• weather compensation parameters/flow temperatures
• picture of DHW tank and surrounding plumbing
• If you have one, a system diagram
• how is it operated - any thermostats or TRVs and if so how are they set (eg 2+C above target temp, to max, or at target temp

If you can post any plots of power consumption (for the heat pump if possible but even the total for the house will do) that would help us understand whats going on also.  If you have a way to get flow temperature vs time that also

I know you have posted some of this already but its helps to keep it all together and anyway if you are starting a new thread it saves switching backwards and forwards.

If you cant do all of this do what you can.

Once we have some more info about the system Im sure you will get plenty of suggestions of things to explore.  From what you have already said I can see a few things, but not that would account for a COP of 1.6 or 2.6.

I will gather thoughts/data and open a new topic. Meanwhile I will continue to hunt for some way to measure the heat output of the heat pump independently of its panel. If nothing else to be able to log it decently. Thanks for the help for now.

Posted by: @carlo

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Meanwhile I will continue to hunt for some way to measure the heat output of the heat pump independently of its panel.

As you know, you need the flow rate to do that, and I think the only way you can get that is to fit a third party meter, which is both invasive and not exactly cheap. But it, plus temp sensors, will give you what you want.

Earlier point about the LG documentation in Italian noted. Can you find an English technical/service manual for the heat pump you have?