You could try https://tools.bregroup.com/heatpumpefficiency/background

BUT

i spent ages on it before realising that the installation is what mattered not the pump. If a very efficient 10kW pump is badly installed (eg. too many room controls 4 port buffer) on a 3kW house then the result will be poor efficiency.

The best option is an installer who knows his product has installed many with happy results, and knows to not add the extra stuff which will ruin a good pump.
The make of pump rarely matters the user interface does.

Posted by: @judith

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You could try https://tools.bregroup.com/heatpumpefficiency/background

BUT

i spent ages on it before realising that the installation is what mattered not the pump. If a very efficient 10kW pump is badly installed (eg. too many room controls 4 port buffer) on a 3kW house then the result will be poor efficiency.

The best option is an installer who knows his product has installed many with happy results, and knows to not add the extra stuff which will ruin a good pump.
The make of pump rarely matters the user interface does.

I cant agree more.  You need

• a heat pump that is right sized (unless you have a thick screed and plan to batch heat to exploit ToU tarrifs to the max)
• connected directly to the emitters (no PHE, LLH or buffer)
• with emitters sized for 45C FT or less if possible, 35 or less if UFH
• and ideally a means to control it (eg to program modest set backs) which is user friendly and results in varying the flow temperature (in addition to the variation programmed in by the WC) NOT turning by it on and off or using a thermostat

The first three are determined by your designer/installer and are the most important factors.

The fourth is a function of the make of heat pump.  Some have controls that do this, others do not.  For many of the 'others' adding homely is an option.  This fourth point is probably the area where, on this forum, we currently dont yet have the data about the different models collected in a useful way and actually havent debated it that much yet.  This is probably because it is the area that currently matters least, because there are work-arounds, whereas if the basics arent right they are difficult to fix (and usually its the basics that cause the problems posted here).

Hi @judith,,

Thank you for that link, I wasn't aware of that website, it's very helpful. I looked for heat pumps to compare to the one we've got (GD Midea 10kW) to get an idea of roughly how it compares - it was very eye opening! It seems that most heat pumps have near identical curves on the graph so basically nothing to choose between them, which reinforces the point that heat pump performance is mainly about the quality of the installation. Another interesting thing was that our heat pump seems to be an outlier, somehow about 100% more efficient than all other heat pumps! Makes me pretty concerned about how trustworthy their marketing numbers are...

It seems that the calculation method used in your tool is much more realistic than the ErP energy efficiency rating calculation method, so why isn't your method - or a similarly more realistic one - being used to inform potential customers about the performance of the heat pump options they have?

Do you work at BRE? Are you aware of this consultation that closes on Tuesday? It seems very relevant: https://www.gov.uk/government/consultations/raising-product-standards-for-space-heating/raising-product-standards-for-space-heating-updating-ecodesign-and-energy-labelling-for-hydronic-space-and-combination-heaters-html

I think your tool would actually be very useful, but the downside is that it seems to be down to the manufacturers to submit their heat pumps to be included, rather than they be automatically included when they are MCS certified, is that the case?

What are the "not valid" pumps in the list? I presume this means do not use, but if that's the case it's odd that they're there at all (I presume this is just pulled from that SAP PCDB).

I like the fact that your tool is clear about which ODT is used for calculating the efficiency/heat loss graph. One thing I like about the Heatpunk tool is that there are quite a few variables to tinker with to understand the potential effects - room temps, flow temp, flow/return temp delta, outdoor temp, mean ground temps (obviously, not very variable!). Obviously not all of these are relevant to your tool, however if it was possible to add outdoor temp as a variable that would allow people to customise to their particular situation.

I looked around again but couldn't find an equivalent tool. The MCS product directory should be the place, but it's impenetrable, at least as far as I can figure out - it's only useful if one already knows the model to look up, rather than be able to set filters and look at what is within those filters. I know that heat pump itself isn't the main factor for heating system performance, but at least making this information more accessible couldn't be a bad thing, could it?

Cheers 🙂

@madbilly I can’t help with most of your questions since I don’t work at BRE. I’m a heat pump customer with a professional science/engineering background who likes finding out about stuff before committing. Paralysis by analysis anyone?

I started inputting to the large consultation but life has got in the way and I may not complete it. In summary it lacks ambition and doesn’t reflect the true issues which are installation not product related. I suspect BRE will have an input.

No heat pump is 100% more efficient than any other, physics doesn’t allow it. You need to assume an error of some kind!

Hi @judith,

Please excuse me, I'd misunderstood when you wrote "i spent ages on it", I thought this meant it was you that made the tool.

I can't believe that all the Energy Rating data isn't stored on some EU database, that must be accessible somehow.

EDIT, I think it might be here https://eprel.ec.europa.eu/screen/product/spaceheaters

I would be very wary of manufacturer's published SCOP data. One very common brand retailed in the UK using Japanese badged up R32 ASHPs has SCOPs that are up to 20% higher at the same air and water combination temperatures than the OEMs own published data. The only difference is the badge on the cabinet. Make of that what you will. 

Posted by: @allyfish

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I would be very wary of manufacturer's published SCOP data. One very common brand retailed in the UK using Japanese badged up R32 ASHPs has SCOPs that are up to 20% higher at the same air and water combination temperatures than the OEMs own published data. The only difference is the badge on the cabinet. Make of that what you will. 

is it possible that the testing regimes are different (eg a different seasonal OAT profile?)

@jamespa yhey probably are, as EN 14511 prevails in the UK and EU. That said, it was the COP data at identical A&W temperature combinations that was markedly different, and they are consistent between OEM and branded supplier. Slight variance in test methodology can't account for up to 20% discrepancy in published data. As good old Scottie once said 'I cannae change the laws of physics'. I know which of the two published data sets I would trust.

That looks as if you’ve found it!

I’ve browsed it a bit now.

The lots of time I spent (wasted) was playing with the BRE tool before I realised that the pumps performance variation was the secondary factor. The dominant factor in household performance is the match (accuracy of survey) to your house, and design of the water system.