Hi James, some interesting and good points there. Just a couple of observations:

1. At 65 C is the SCOP 3.5? I thought it was lower, a quick search on tiniternet suggests so https://www.theheatinghub.co.uk/articles/high-temperature-heat-pumps

2. If we mass retrofit at a lower SCOP the electricity demand will be higher, how will the country meet this demand? Nuclear power stations seem to be the govs big idea, but large ones take ages to build and I cant see micro ones being popular either (NIMBY) Just something else that occured re micro nuclear power stations is security.

3. Perhaps a different policy should be adopted for different geographical areas? Its much milder in the South and easier fo heat pumps to be efficient. Politically difficult, I accept.

@bontwoody 

1. I have yet to find a manufacturer that quotes SCOP at 65C.  What I did was create a model based on published cop at various flow temps and outdoor temperatures, weather compensation, and the annual distribution of outdoor temperatures (in the South East).  I don't necessarily trust the absolute figures, but the degradation (provided you run WC) between running at 45 and running at 65 whilst large, is no so large that the latter should be rules out. 

Bear in mind also that, in talking SCOP, we are dealing with the reciprocal of what really matters (ie energy consumption).  This gives a distorted impression.  The difference between a SCOP of 1 and a SCOP of 3 really matters, its a tripling of a high energy use.  But the difference between a SCOP of 3 and a SCOP of 5 doesn't matter anything like as much, its only a 40% increase on a rather small energy use (and only 13% of the consumption at a SCOP of 1).  

2. Yes, but that's a separate problem.  We know we MUST go electric so those responsible for this need to solve it.  Reducing the SCOP of the deployed solution from say 4 to 3 isn't likely to be the dominant factor (see above), its the switch from gas to electricity.  A proposed alternative to heat pumps is hydrogen, that takes 4* the electricity of a heat pump with a SCOP of 3.

I think the problem is largely one of distribution during peaks, not so much generation.  This may ease somewhat as batteries and electric cars smooth out the load.  But either way its a totally separate problem which must be solved else we are toast.

3. With the current state of technology I think you may well be right.   As heat pumps get more efficient at higher temps (they are no where near the limits of the physics) this will likely change.  We have to start somewhere.

@jamespa Well Im convinced, but there something in preaching to the converted 😆 

It just occured to me that your high temperature solution could be successfully coupled with a change of government incentive. Instead of giving 4K for a low temperature install, just take the cheaper high temperature route and the Gov would pay for a PV array and subsidised battery, thus helping the grid production and infrastructure at the same time?

@bontwoody Yes true. Having said that I would personally prefer to have (or at least trend towards) solutions that don't rely on government subsidies.  I'm not against them, but they are unreliable and subject to political interference.  

If the requirement for MCS to get PD (which is quite abhorrent) were scrapped, and a bit of incentive and basic training offered to local plumbers on how to assess whole-house heat loss reasonable properly (an assessment which is, after all, easily checked against actual gas consumption!), then my 'solution' could potentially be deployed by the same local plumbers that today retro fit most boilers. 

Currently we have gone for the Rolls-Royce solution which involves ripping out most of a heating system to change the boiler (that's the net effect of a HP retrofit as far as the end consumer is concerned).  We need the VW Golf (or ID3) solution as well.

@jamespa I think you're ideas are interesting , but there's one key area that I'd challenge - the assumed capability to achieve a reasonable COP in practice, in a straight "swap the gas boiler for a HT heat pump and do nothing much else" retrofit,  for a usable proportion of the installs that you'd expect the local plumber and his electrician friend to take on.

If that reasonable COP is not achieved (for sizeable majority of the installs) and the homeowners are left with a COP right down at the low end then their running cost will be painfully high and they'll be shouting "my heating costs too much to run, help". Which is no good for anyone, the homeowners, the local plumber, or his future business model. Unless he has a "swat team" to call on who'll deal with the cases where the homeowner is left in practice with an inefficient and costly-to run system, he won't be prepared to take on the risk of having to sort that himself afterwards on a fixed-price type install. So he'll either not take it on, or price in the internal improvements that takes us back to where we started.

there are so many people who've come on this forum with poor COP's  / poor heat transfer situations from installs that really should have been done in a way that delivers mfr spec COP. if the suggestion is now "don't worry about that extra stuff, just swap the heat source" then I can't see how that proportion of people complaining about performance / run cost will do anything other than get worse.

if the potential for high run cost can be mitigated against by bringing electricity prices down so that even a COP of 1.5 gives run costs that are "acceptable" to mr joe public, then maybe this works. we move to a model of electric heating on an efficiency that's at least better than direct, and accept that we're not aiming for the "most efficient" model, just a "get everyone off gas and don't make them worse off" model. then if people want more efficient, they can choose to invest more for those internal improvements that make it so.

@iancalderbank I agree its a risk, but as you say it happens already.  So I currently face paying a large amount of money to an (often fly by night) 'MCS accredited' company that has come out of nowhere to do an install which all too often doesn't work.  Wouldn't I be better of paying a smaller amount to a local plumber that values their reputation, intends to stay in business for the foreseeable future, so is likely to do a good job?  Currently these guys are excluded completely from the market by the regulation and the insistence on 'MCS Standards'. 

Honestly I know which one I would trust more!  I'm not saying that we should mandate 'just swapping out', only that we should allow it rather than (effectively) disallowing it.

@jamespa I totally get your point as to what you face, when viewed from your point of view as a physicist and engineer , it makes no sense. I reached much the same conclusions, and so, I used local plumbers and electricians for some parts of my work and did the rest myself. 

No MCS company was involved in the ASHP. an MCS company (who were very very good) did the solar and batteries. I'm wondering if its been easier for this all to work with solar/ batteries because there isn't as much difference from one house to the next , or in the possible system designs, with those technogies, as there is with heating.

 I've been thinking about this from the point of view of a relative  who's moved into a victorian house, 3.5m high ceilings, single glazed, draughty , boiler thats perhaps 30 years old (definitely not a condenser!), tiny radiators. When we visited at xmas, his system (when he got it to work at all) was running at FlowT of 70 or perhaps more to keep the house warm.  A classic case of desperately needs a complete system refit.  But I cannot, despite really wanting to, recommend to him that he goes and gets a heat pump (even though he would quite like to, he is "green aware"), because I know that without substantial upgrades to the system and house, it'll cost more to run than the ancient boiler, and more to install as well even with a BUS (and having just bought a house, he is not flush with cash). So I'm thinking of that scenario when I think of "mr joe public" - yes a HT heat pump would almost certainly heat his house without changing his rads - but the run cost would be terrifying. he also lives 150 miles away so I couldn't babysit the install for him. and not every joe public has a geek friend or relative to help out anyway.

so for me

• No Vat on HP at purchase - regardless who/where/how. It really got on my wick that they announced that and then there's the "oh yeah you only get zero vat  as part of an MCS install...grr..."
• BUS if Boiler swapped for HP - for all . regardless of by who or how. Boiler removal part to be by a GasSafe engineer who signs off that its was previously in service and this audited against premises recent gas bills and boiler servicing bills to prevent fraud on the BUS.
• Additional grant support above and beyond BUS for low-income people (means tested) to genuinely get the install price down to same as gas for them.
• Grant support for electricity price for HP use to be same as gas to get the run cost equal or better. Requiring separate input metering prior to any structural changes in the market like moving the green levy (if ever...)
• any qualified plumbing and heating contractor to do the work
• an umbrella organisation providing support and advice to those heating contractors , with their decision making as to what system design  and HP type to use. and providing a warranty (And access to swat team of Seasoned Veterans to troubleshoot) if there are performance issues.

Can I cross-post your proposal (with credit or without as you prefer) to buildhub.  There are some reactionaries on there who seem to criticise everything (including MCS) but refuse to be positive about any suggestion for change.  Actually your package seems a good one and it would be interesting to get their reactions.  Only if you consent of course!

PS,  I started this because I am interested in understanding potential, not for me (I've pretty much worked that out), but more generally.  My current perception is that the market simply isn't working, and I'm yet to be convinced anyone is fixing it.  Yet it needs to be fixed.  Hopefully its read in that light.

@iancalderbank Your proposals are indeed sensible. Opening up the installation of heat pumps to a wider set of people will probably not result in too large a dip in installation standards. Indeed we should be encouraging a grass-roots approach to the energy transition, helping people like yourself do it for themselves. These long supply chains really inflate the cost.

The Boiler Upgrade Scheme gatekeeping is understandable, but has resulted in poor uptake and some poor quality installations by chancers who know how to use something like easy-MCS. The idea of getting a gas-safe person to verify the de-installation is novel, provided the BUS grant scheme checks building control for a subsequent re-installation of a gas boiler.

Posted by: @iancalderbank

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No Vat on HP at purchase - regardless who/where/how. It really got on my wick that they announced that and then there's the "oh yeah you only get zero vat  as part of an MCS install...grr..."

At the risk of being pedantic, the zero rated VAT on energy saving measures (link) does not mandate the use of MCS. I am considering putting materials and subcontracting (heat pump and IWI and suspended floor insulation) through my own VAT registered limited company, although for a 2k saving all the paperwork may turn out to be a bit of a chore. But for me the principle is important!

As above I think this is a good list

I would add

• Permitted development rules modified so that the noise condition set out in MCS-020 applies but not the conditions which require the installation and design to be done by an MCS registered contractor to qualify for PD

Without this the market barriers to new entrants remain in place.  

In terms of comments on your list, politically I would consider splitting it into two, those which open up the market and those which reform the grant regime.  The former is easier than the latter and I have a feeling that some sort of 'certified standards' regime may be either necessary or highly desirable for government grants, either under EU rules (which likely still apply) or 'best value'.  I am told (unverified) that MCS was invented to satisfy the EU that we had a certification scheme.

More specific comments

• No Vat on HP at purchase - regardless who/where/how. It really got on my wick that they announced that and then there's the "oh yeah you only get zero vat  as part of an MCS install...grr..."

This plus the PD change alone will open up the market.  Maybe it doesn't provide sufficient incentive for plumbers to engage, but it at least removes the barriers.  

• Grant support for electricity price for HP use to be same as gas to get the run cost equal or better. Requiring separate input metering prior to any structural changes in the market like moving the green levy (if ever...)
  • or better still (and more saleable perhaps) reform the current artificial pricing model which, by regulation, discriminates in favour of gas

and this one has multiple effects.  If, for example, electricity were only 2.5 times as expensive as gas, most of the arguments against the proposal with which I started this thread fall away, even with a relatively poor (albeit not the absolute worst) install.  If electricity were only twice as expensive as gas, they fall away completely even with a very poor install.  At this point most of the ancillary work can be dropped or become optional, which reduces that actual cost by 5K or more and means installers can spend more time on setting the system up.  Running cost parity with gas is sufficient if the install price is sufficiently low, there is no need to squeeze the last 25% of efficiency out, this can be offered as an upgrade  (its my strongly held opinion that the current methodology of compulsorily swapping out more or less the entire heating system must change, one way or another, I just cant see it ever being saleable when the alternative is a simple boiler swap).

• BUS if Boiler swapped for HP - for all . regardless of by who or how. Boiler removal part to be by a GasSafe engineer who signs off that its was previously in service and this audited against premises recent gas bills and boiler servicing bills to prevent fraud on the BUS
• Additional grant support above and beyond BUS for low-income people (means tested) to genuinely get the install price down to same as gas for them.
• any qualified plumbing and heating contractor to do the work
• an umbrella organisation providing support and advice to those heating contractors , with their decision making as to what system design  and HP type to use. and providing a warranty (And access to swat team of Seasoned Veterans to troubleshoot) if there are performance issues.

I can see the above being supported by manufacturers but fiercely resisted by installers who are incentivised to protect their monopoly position.  A good counter-argument could be that it engages the army of plumbers out there who currently are (effectively) excluded and thus liberalises the market, whilst maintaining protections on quality.