Thanks @l8again

We crossed posts. That answers the question about additional equipment, although I’d still be interested in Heat Geek explaining how they check the reliability of the figures used to assess the guarantee, rather than simply how they access them. I’m not suggesting that the absence of a separate meter means anything is wrong, but I think it’s a reasonable question when the measured result is what determines whether a promise has been delivered.

Your concern about changing settings is a fair one, and I can see both sides of it. I wouldn’t expect an installer to stand behind the same efficiency figure regardless of how far somebody departs from the agreed setup, but equally, I wouldn’t want a homeowner feeling that their heating controls had become a minefield where touching the wrong button might undermine their protection. For me, the distinction is between ordinary adjustments to suit life in the house and changes that fundamentally alter how the system was designed to operate, and I’d want the installer to explain where that boundary sits... but that's me.

I’d also ask them to distinguish clearly between the equipment warranty and the efficiency guarantee, rather than leaving you to assume that the same conditions apply to both. 

The other thing I’d clarify is your assumption about automatic alerts, because knowing that somebody can look at the system isn’t quite the reassurance of knowing that they are watching for problems. Your approach of following the installer’s advice through the first winter sounds sensible to me... I’d just want their monitoring and support responsibilities to be as clearly understood as your responsibilities as the homeowner.

@editor 

I think there is a legitimate discussion here about what its practical to expect.  If we can agree, which I hope we can, that a SCOP guarantee is actually (much) more valuable to the householder than a figure for FT, what is it reasonable to expect someone who offers that to provide.  And is it really in the customers interest to ask them to fit specialist measurement equipment to every installation particularly when, like Heat Geek, they have data from thousands of installations that are not encumbered with buffer tanks or other problematic design 'features'.

Guaranteeing SCOP is, IMHO, a significant maturing of the market, which really should become universal.  In the end its the main figure that matters once the house is warm enough and you are happy with the installation price.  However it would be a pity if it does become universal (or more widespread) at the expense of a significant increase in installation cost.

When you buy a motor car they dont offer to monitor mpg, although these days they definitely can and possibly do.  The expectation is that you will return it to the dealer if it is underperforming.  I would accept that heat pumps are not a direct analogy, but at the same time I would not want to expect things that involve a lot of additional cost. 

Answers on a postcard!

Ps this would make a great podcast with two protagonists, a householder and a moderator.   Detailed design information Vs guaranteeing the thing the customer actually cares about!

There are a couple of points that I think are worth mentioning.

Heat Geek has previously published that its installations averaged about 4.2 SCOP for heating alone, with Elite installations around 4.48. When hot water was included, the Elite average fell to about 4.26. They also reported that predicted heating SCOP averaged about 3.85, versus actual performance over 10% higher. 

As we know, the Heat Geek Guaranteed Minimum SCOP is a total performance warranty. It follows that for a customer like me who hasn’t had the hot water cylinder changed, the overall performance for the heat pump in heating mode has to be a higher than the guaranteed minimum to offset the ‘inefficient’ hot water cylinder.

My calculations - helped with a bit of AI - suggests the following:

Space heating SCOP: 4.2–4.5
DHW SCOP: ~3.1–3.5
Combined: ~3.9–4.1 (Heat Geek Performance Guarantee)

The truth will out this coming Winter.

Is it possible that a guaranteed SCOP could potentially hide the fact the installed ashp is in fact undersized for the application? 

@iaack 
In my case, the Zero Disrupt quote was based on a 5kW Valliant for a 5.86kW heat loss. After updating 8 radiators, the quote changed to a 7kW Valliant. Both heat pump sizes are capable of supporting a 5.86kW heat loss.

@jamespa, fair points, but I think we may be conflating two separate things... supplying the proposed design flow temperature before installation and fitting specialist monitoring equipment afterwards.

Publishing the design flow temperature shouldn’t add any meaningful cost. It should already form part of the system design surely? It gives the homeowner an important indication of how the quoted performance was calculated and whether the system is likely to operate efficiently. I don't fully understand why it's withheld unless HG aren't calculating it to begin with which would be equally odd.

A guaranteed SCOP could certainly be more valuable, IMO, but only if the guarantee is transparent, independently measurable and backed by clear terms explaining exactly how performance will be assessed. Heat Geek’s wider installation data is useful, although the figures I saw suggested they were still well below 1,000 completed installations when this initiative launched (but that’s a conversation for another day). Either way, portfolio wide data cannot replace evidence from the individual property when a homeowner believes their system is underperforming.

And yes, this would make an excellent podcast. Do I need to get Mr Chapman on the show as well? 😂

Posted by: @editor

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Publishing the design flow temperature shouldn’t add any meaningful cost. It should already form part of the system design surely? It gives the homeowner an important indication of how the quoted performance was calculated and whether the system is likely to operate efficiently. I don't fully understand why it's withheld unless HG aren't calculating it to begin with which would be equally odd.

Posted by: @l8again

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@iaack 

In my case, the Zero Disrupt quote was based on a 5kW Valliant for a 5.86kW heat loss. After updating 8 radiators, the quote changed to a 7kW Valliant. Both heat pump sizes are capable of supporting a 5.86kW heat loss.

That’s precisely why the design flow temperature and underlying calculations are so important IMO. If the heat loss remained at 5.86kW, upgrading eight radiators should have enabled a lower flow temperature, so why did that result in the heat pump being upsized from 5kW to 7kW?

There may be a perfectly reasonable technical explanation involving output at the design conditions, modulation, hot water recovery or noise limits. However, without the design assumptions being disclosed, the customer has no way to understand or scrutinise such a significant change. Did Heat Geek explain the reason for the upsizing? 

@editor 
How many installers actually give both a maximum flow temp and SCOP? I believe that Octopus gives a design flow temp and a standard estimate benchmark SCOP rather than a bespoke design SCOP.
FWiW, my installer said that I was looking at an extra £1000 for OpenEnergyMonitor. I know that he has installed it on a number of his bespoke installations which appear in the OpenEnergyMonitor performance tables.

@l8again from memory (and I am quite happy to be corrected on this) I think MCS has for some time expected flow temperature and predicted performance to be presented together, rather than asking the customer to choose which of the two is important to them. I think that the MCS pre-sale performance estimate/quotation needed to include the proposed flow temperature, anticipated SPF/SCOP and an estimate of the heat pump’s annual electricity consumption. 

I also seem to remember that the MCS performance-estimate process went further and translated those figures into an approximate annual running cost, potentially allowing the customer to compare the proposed heat pump with their existing fuel. I've not stayed to speed with the MCS requirements, but I'd see no reason why any of this stuff would have been removed.

I'll ask some of our installers what the current requirements are. 

As for OEM, that seems very high. I think the OEM kit is selling for around £500, so that's a nice tidy mark up if it is.

@editor

I think you may be somewhat missing the point here, perhaps over influenced by the way the industry has conditioned us to think and, in a way, arguing against a change in the industry which you yourself have consistently (and rightly) campaigned for.  I would like to illustrate this by considering the counterfactual. 

Suppose that the heat pump industry had, from the outset, offered as standard a guarantee that your house would be sufficiently warm and that the system would exhibit a minimum SCOP.  Suppose that the only additional information it had provided was the physical sizes and appearance of components including radiators.  Furthermore suppose that MCS or another body held installers to their promises, or simply that installers just did the job/honoured their guarantees and those that didn't were called out through reviews or other means.

Had this been the case there would be no need for homeowners to learn about flow temperatures, buffers, flow rates and all the other things that you and I regularly emphasize (and satirize) as necessary for consumers to know.  Instead all that consumers would need to understand is the things that they actually care about.  The renewable heating hub would not need to exist (other than as a place to call out installers who did not honour their specs), ordinary people would not need to learn the language of heating engineers, and buying a heat pump would be just like buying almost any other product (where you don't ask or care about the technical design details, only the end performance and price).  Happy days!

Now imagine that someone popped up and said, wouldn't it be great if, instead of telling people this simple information that relates directly to something they care about, we give them the detailed construction specifications.  Then we (as installers) are let off the hook if our design turns out not to deliver a sensible efficiency, the customer can spend hours fascinating themselves with the technical details, self help groups would pop up to discuss this in detail and people might even publish books advising consumers how to interpret it.  How do you suppose this person popping up suggesting the change would be received in the consumer space?  For sure some installers would be delighted, but from the consumer point of view thats rather less likely.

What Heat Geek appear to be doing is pioneering a sea change in the industry and, in my view, we need to give them credit for that.  They are taking some risk in doing so, not least in terms of the MCS design specs, but the risk they are taking is presumably calculated and from a consumer point of view necessary if the industry is to get to where we would surely all like it to be.  Of course if there is evidence that they don't deliver then that should be loudly be called out, but so far there is none here.

@jamespa, I think your counterfactual is a powerful one and in principle I agree with its destination. Homeowners should not have to become amateur heating engineers simply to protect themselves from a poor installation. If every installer gave a clear, enforceable promise that the house would be warm and that the complete system would achieve a stated minimum efficiency, with reliable monitoring, meaningful independent oversight and a prompt remedy when it failed, then much of the technical self-education we currently encourage would become unnecessary. RHH would also not exist.

Heat Geek deserves credit for attempting to attach commercial accountability to an outcome that most of the industry has treated merely as a prediction.

Where I differ slightly is in the suggestion that an outcome guarantee makes the underlying design information unnecessary, or that asking for it somehow argues against this change. A guarantee sounds beautifully simple at the point of sale, but the moment a system falls short, the definition and measurement of the promised outcome become extremely important. Heat Geek’s guarantee, for example, concerns combined heating and hot water efficiency measured over 365 days; it depends upon monitoring, servicing, the customer retaining the commissioned control strategy and various other conditions, while the agreement also gives Heat Geek opportunities to rectify the system before a refund becomes available. That is not a criticism of the guarantee... it is simply an illustration of why even a seemingly straightforward promise inevitably depends upon technical definitions, evidence and contractual detail.

I also would not regard the design flow temperature as an obscure construction specification (that's a mouthful) that consumers are being asked to understand. It is one of the principal assumptions underpinning the efficiency being offered, and it can be communicated in a single line with a few key numbers. The homeowner is perfectly entitled to ignore those figures, just as most drivers ignore much of a car’s technical specification, but the information remains available to an adviser, an independent expert or an adjudicator if the promised result is not delivered. 

My position is therefore "both", rather than "either/or". We should welcome Heat Geek putting its money and reputation behind comfort and measured efficiency, and I would be delighted if that approach became universal. At the same time, I do not think a guarantee should be used as a reason to provide customers with less information about the assumptions on which that guarantee was calculated. In fact, a confident installer offering a meaningful performance guarantee should have no difficulty providing both the simple consumer promise and the key design information supporting it.

I also accept your final point... nothing posted here so far demonstrates that Heat Geek is failing to honour these guarantees, and it would be unfair to imply otherwise. Most installs have been through one winter, but it'll be interesting to see where we are come Jan/Feb next year. That is precisely why I want to hear from actual customers and examine how the guarantees operate in practice. If the evidence shows that Heat Geek is delivering what it promises, that deserves to be reported just as loudly as any evidence showing that it is not.