JamesPa

The important thing with ashp system design is KISS. You just need a correctly sized (not grossly oversized) ashp connected directly to the emitters with a diverter valve to the UVC, maybe a volumiser, (almost) never a buffer. No external controls, not even a thermostat. No glycol, use anti freeze valves. Use the ashp controller to set the weather comp curve as low as possible and leave ticking over 24*7 (unless you plan to batch charge your slab to use it like a storage heater which is a whole different design). Choice of ashp itself not so important, but some have better controls, quieter, less ugly etc than others. Many of the ones with poor (personally I would say inadequate) controlled can use homely, an external physical controller, or havenwise, a virtual controller service) as an overlay. Under no circumstances fit any smart thermostats etc other than these (or adia) which are designed specifically for heat pumps. Reject any installer who is going to install a buffer, phe or llh between ashp and emitters, or external controls other than those mentioned above. Be suspicious of any installer who specified a 'pre plumbed cylinder'. This is often an indication that they are employing rookie plumbers and some pre plumbed cylinders come with built in llh. Post back for explanations of the above if needed.

... Which, if I follow through on the logic above, is apparently entirely fair, because they wouldn't have charged Roger as much for the infrastructure upgrade needed to support his load had there been an additional house on the pole.

I agree there is little point in continuing the debate because you appear to think that a utility that we all pay for should provide infrastructure to support what you want free of charge to you, so the rest of us have to pay, even though your requirement is out of the ordinary. Like it or not its your load that is abnormal and it's entirely irrelevant to the argument that there are some hypothetical circumstances in which the dno could accommodate you cheaply. Those circumstances don't exist. What does exist is your abnormal load and the rest of us shouldn't have to pay for it. Hopefully one of the suggestions others are making will work.

How do you know that the money isn't to pay for infrastructure upgrade. I'm not a power engineer, but I can think conceptually of two ways to spend the money and solve the load balancing problem namely: Fit a 3 phase transformer (and any necessary supply from the next station up the line) and insist you run split your load between at least two of the phases or Retain single phase but upgrade the return (neutral) cable to the next splitting point so the phase imbalance is statistically diluted and the cable loss reduced. There are probably other ways. Did you actually confirm that the figure you were quoted involved NO infrastructure upgrade at all? Even if there is no infrastructure upgrade then your abnormal load still costs the rest of us money unless you contribute, because the phase imbalance results in network losses which we all pay for. It could be that they take a view on that but charge it as a one off fee. I'm sorry but the bottom line, which I know you don't like, is that you have an abnormal requirement and so you should pay an abnormal fee, which is what you are asked to do.

Pay for the necessary infrastructure to support your unusual load?

No of course not. But neither should we all pay for their indulgences. The reason you need more than a normal domestic load is because of your unusual needs, not because of a heat pump. You have chosen to prioritise the former. In an ideal world the dno would charge you more for your unusual needs whether or not you need an upgrade, then do the upgrade to support the heat pump as well foc. But that gets very complex, it's a niche case, so it's unlikely to make sense overall even if it does in your case. One possible solution is probably the French one where you tarrif depends on peak consumption, but doubtless that also creates anomalies. You can't expect the whole world to be designed around your niche circumstance. You will have to live with the fact that your choice to have unusually high needs and not to be willing to pay for the supply required means your options are now limited.

It adds little or no value unless there is a very specific reason for it, and it's another component to pay for, go wrong, and complicate any problem diagnosis. Also complicates weather compensation (are you planning a weather compensated mixer for heating, if not how do you plan to achieve this?) Heat pump still has to produce the higher (or lower in the case of cooling) of the two temperatures, so that defines the efficiency you will get. What's the added value of running at two temperatures? I agree that getting them to fit the ASHP then doing the associated cooling parts is probably the best solution here

There is a further side to this. If the demand is such that 3phase is either advised or required, then dno will be concerned about phase imbalance if they supply it all on a single phase. Having alerted them to a 3phase requirement it would be entirely reasonable of them to be suspicious of a revised single phase specification which exceeds the domestic norm. Hiding behind it being a spur off of a connection to the house isn't going to help. DNO had a duty to protect the (shared) network for the benefit of all. There are good technical reasons behind restrictions on single phase supplies.

I agree with @JohnMo, but installer may still refuse even if you run above dew point because he won't know anything about cooling and wouldn't want the responsibility and you probably haven't paid him to do a design for cooling. So don't tell him, make sure he fits a system that is capable of cooling and which can measure and control to dew point (check specs yourself if necessary), then run above dew point also without telling him. If you are worried this will invalidate your warranty, which it just might, then you may need to pay for a cooling design!

80A is surely enough for your ashp, EV and domestic needs, even 60A could be made to work. If you need more for non/abnormal domestic purposes it's right that you should pay. Earlier on this thread you used the DNO position to justify your statement that government isn't serious about carbon reduction. Was that really a fair statement given what you have subsequently told us about your use?

Can you clarify please, I thought I'd addressed your comment but maybe I didn't understand it!

Sorry I agree with @JohnMo. Eliminate the zoning (and the heatmiser), balance the loops, let the Mitsubishi controller do what it was designed for. Your problems will likely vanish and equally likely you can turn down the flow temperature, save yourself money and have a more comfortable house. Unfortunately the manufacturers of controls have, over the years, seduced us into thinking that micro zoning in time and space saves money and is somehow desirable or necessary. Even with a boiler (and excepting very lossy or very long and thin or otherwise oddly shaped houses) this is unlikely to be true, and is certainly not true to the extent we have been told by those with a vested interest in us buying their products. With a heat pump (admitting the same exceptions) it's almost definitely not true. Likewise ignore me if you wish!

This is true, but is a consequence of our grid not habug the right interconnections - it was.set up to supply power from a few concentrations of coal plants in the Midlands and North. Shifting power from thr coast is harder. Sometimes there isn't enough capacity to shift the power I am told by someone I trust on these matters is that this is not the principal reason. The same person says that the principal reason is that there is a type of gas powered station that can't economically be turned down for less than about 24hrs, so to balance the grid other more flexible sources must be attenuated. He also says that NESO's green objectives mean that by 2030 these will have to be eliminated. In other words there is a plan. This is fair enough, infrastructure takes time to change and the future demands are not fully predictable particularly with a volatile political climate. Sometimes, if you bother to find out the facts, actions of government become much more understandable than click bait sound bites, motivated by self interest, would like us to believe. For this reason my personal opinion is that it's best either to ignore or take with a pinch of salt such mischievous reporting designed solely to undermine experts and the government but actually with little foundation. And yes @MrPotts it gets added to our bills, as it should because it's part of the cost of providing the ever present access to exactly the amount of electricity we want precisely when we demand it. If we were more flexible then some of the infrastructure costs would reduce, but we aren't. He also says that the elimination or reduction of these sources will likely result in nighttime TOU tarrifs becoming less favourable.

Some do for sure, but some don't. If you want to go mad there are some really swanky looking ones available in Italy, at correspondingly swanky prices. Actually the Mitsubishi ones are made in Italy and IMHO look better in 'real life' than in their publicity leaflets, because the stylistic curves have more impact. Thats the one niggle with the Mitsubishi model. It does have different thresholds for heating and cooling, but they are not adjustable. The cooling one is fine (18C I think) but the heating one, at 30C, is a bit high at the beginning and end of the season. For me that hasn't yet been a problem because the room its in has solar gain, so when the fancoil doesnt come on because of the threshold, the sun is heating the room anyway. However that wont be the case for everyone and, personally, I think they should allow the threshold for heating to go as low as 25. You need to set the coolant temperature above the dew point. My Vaillant measures dew point and does that by default (once you have enabled cooling with their overpriced dongle, or the with the exact same dongle, but at 1% of the price, sold also for coding their gas boilers). Doubtless at least some other makes will also control for dew point. @JohnMo is of course spot on about power output. Mine and many others modulate their fan according the the settings and/or the set temperature compared to room temperature. It seems to work well. The one thing to watch is that they have essentially zero water volume, so if you have a lot of them you are likely also to need a volumiser.

I cant see why, with a little ingenuity and assuming no industrial power tools, 60A isnt sufficient anyway. The baseload can be taken as 10-20A for an EV, 32A for a Heat pump (only when its really cold and even then probably only for relatively short periods) plus the standard 400W=2A that we all have as baseload for our misc electrics. That fits within 60A. This will of course be exceeded when washing machine, iron, cooker, immersion heater or dishwasher are doing heating, but during these periods, which typically last an hour or two max, either the EV or the heat pump could be turned down/off. Many EV chargers are capable of measuring supply current to limit output, and all heat pumps can be switched off temporarily either by a dedicated contact or using the call for heat. To my mind there is a very strong argument that we should all be compelled (or very strongly incentivised) to limit our demand to 60A to reduce the need for expensive electricity network infrastructure upgrades. France already, I am told, has tariffs which depend on max load, no reason why we shouldn't. To do things 'sensibly' as opposed to at unnecessary great expense both in terms of money and resources, we have to get out of the mindset that says we can have anything we want whenever we want it and into a mindset which allows some, very modest, compromise! As it happens I don't think I have seen my total instantaneous house consumption exceed 5kW since my heat pump was installed and my EV acquired, but that's influenced by the fact that I only have a granny charger and a 7kW heat pump.

They are certainly more expensive (although not so much so compared to a large type 33) and do need a power supply (just a few watts so the cable can be small!). Im not sure convector radiators are terribly pretty! Faced (at 45C target flow temperature) with the choice of a radiator 1600mm*600mm*200mm type 33, in a space where this only just fits without obstructing a doorway, and a Mitsubishi i-life slim 937*579*131mm and which could also do cooling, the choice for me at least was clear. In place it looks very smart indeed, but of course beauty is in the eye of the beholder. I think the point to be made is that they are worth considering when the size of rads would otherwise be unwieldy and/or in rooms where cooling might be desired. Of course we all really want UFH operating at 35C or less, but in a retrofit that's not always practical.

The oil companies strategy on climate change has been clear all along. First deny it, which they succeeded in doing for a long while (even though their own scientists told them about it), then argue for delaying action now it has become clear that their denials are simply lies. Eventually (if we allow them) they will shift to arguing that action is pointless and that instead we should buy even more of their products to 'protect ourselves', which of course we can never do because continuing to burn fossil fuels inevitably means that climate change gets ever more severe. However while we do so we will still be buying their products so they wont care. They pay vast amounts to consultants and others to represent their case, and fund election campaigns (in countries where this is legal) for people who would support them, They arrange things so that much of the media sing their tune. Unfortunately many people, including some here, appear completely to swallow this misinformation campaign and instead echo their most recent mantra, and blame politicians, who have limited power, need to win elections, and have a job that relatively few actually aspire to (unless they are totally power-crazed in Trumpian fashion which, frankly, relatively few of ours are so far as I can tell). Despite this they still haven't quite succeeded in 'controlling' governments, who thankfully, continue to do things that are contrary to their interests No politician is perfect of course, but neither can we expect them to be. They are only humans and have to operate in the real world and, faced with such a barrage of attack from those with vested interests, necessarily will moderate what they are doing (or how they represent what they are doing). The fact that the oil-sponsored media are constantly criticising the measures ours and other governments are taking to mitigate climate change is, in a way, good news, because it means that they are worried that it might actually have an effect on our consumption. It now appears more likely than not that China is on a mission to benefit bigtime from climate change, by making bold steps towards cheap energy and dominance of the markets. We can sit in the backwaters slowly watching what remains of the historical benefits of our imperial legacy vanish completely (both in terms of global influence and wealth inherited as a country from our not-particularly-nice forebears) , or we can remain on board. I say remain, because we are still one of the leaders, notwithstanding the previous government's attempts completely to destroy our credibility on the global stage. Neither is guaranteed to work, but the former is guaranteed to fail and is also completely devoid of morality. So for me the path is clear. Yes, we must do what we can to mitigate, to the extent we reasonably can, the 'baked in' effects of climate change, but we must also do what is necessary to stop them getting more severe than they need to. If that costs a lot of money, so be it, because the alternative costs even more. We remain a relatively rich nation (even though the wealth is unfairly distributed); we can afford it if we choose to. Currently we do choose to, not fast enough maybe, with some rough edges maybe, with a little hesitancy certainly, but nevertheless we are as a country pursuing a course which should result in a material reduction in our emissions and, so far as I am aware, not failing materially to invest in measures to combat the effects already baked in. By carping on about individual facets of the plan we risk throwing out the baby with the bathwater (as most now accept we did with Brexit) and surrendering control entirely to those who are truly self-centred, who seek power for the sake of power and who will do the bidding of big oil. Is that the route we want the country to take?

Actually I think there are quite a few politicians of several political persuasions that do care, and my voting choices are based at least in part on who appears to care more from the available choices. However they are imperfect humans with limited control. I don't expect to agree with or like everything that any of them do, that's not realistic, which means I will always be able to point at things which are 'wrong'. That's the nature of living in a democracy and in a pluralistic society. But if I reject people just because I don't agree with everything they do I am left in a hopeless position. Better a moderately competent politician with some degree of logical thought and at least an element of caring, than someone totally devoid of morals who exploits and says anything they can to get into power.

That's an outside influence that it's subject to. But not controlled by (so far as I can see) as you claim. How on earth are a raft of largely small businesses that make up the customers for mcs 'controlling' government? And are any 'getting rich', relative at least to people like Bezos, Musk and Zuckerberg? No of course not (I'm not defending them btw). Maybe the influence of outsiders on government is too great. Unfortunately we have spent years trashing our civil service so they probably don't have as much skill as we need them to have to argue with the vested interests. However that is a direct result of penny pinching politics and siren calls for lower taxes. Are you prepared to pay more so we get the very best people in our civil service (which is imho what we need)? What goes around comes around!

I think that ship sailed (or it's course was set) in the 80s and we have subsequently become addicted to indefinite amounts of cheap 'stuff', another source of climate change. Currently the government is trying to save eg the steel industry in case it escaped you. As to the balance of your comments, I'm not sure anyone is disagreeing with many of them individually, although there are financial implications of some of them which might meet resistance, and I'm not sure who you think is treating us 'like naughty schoolchildren' or calling people evil monsters (unless of course you think that merely advocating change is equivalent to calling people naughty schoolchildren or evil monsters, in which case we can never make any change). However they don't collectively amount to an alternative 'big plan' for dealing with climate change, which is what Roger appears to be suggesting we need, they are more like tweaks to the current plan.

I did think about all of this when I got mine. But I can't see it's a material risk any more than with any other piece of modern equipment or indeed a modern boiler. Ashps come with a controller which is part and parcel of the ashp. It may be physically separate but it's effectively the same as the electronics that come with (usually in) your boiler. So expect to replace these just as you expect to replace the boiler embedded electronics. Control connections to and from are typically a 2 wire bus, and the wires can be used for a different bus. Even if they can't it's a passive cable, hardly a disaster if you need to run another passive cable. Reputable heat pump manufacturers are busy training installers, so the numbers will grow. Vaillant were able to name 3 within a few miles of me and as demand grows the numbers will grow Heat pumps, apart from their electronics largely use fairly standard components, just like boilers. Much of the conversion cost from boiler to heat pump is the rest of the system, which is almost all independent of precise model. In summary all the conditions are there for both maintenance and replacement at reasonable cost. Of course the industry may try to 'price gouge' but that's a risk with any purchase. I do agree that heat pump MPs shouldn't be sold on savings on running costs relative to gas (although it's perfectly possible to do so), that's unless a guarantee is offered (I believe some suppliers do offer such a guarantee). Personally I would be happy to recommend to an informed friend, but not to someone who for whatever reason was predisposed to declare it a fail as some people clearly are.

Is it? I grant that it's subject to outside influences (as Liz Truss discovered) but that's not the same as controlled. What evidence do you have for your assertion?

Ok so if you do only the latter the effects of climate change get ever more severe. How do you 'prepare' for that, what do you do about the millions of people who are displaced as a direct result of our excesses, and how do you persuade people to vote for your plan? And where do you and other individuals fit into this, do we have any individual responsibility or is it all for 'Government' to fix (which, if it is, is weird given that it's individuals that cause climate change not governments). Your approach (based on what you have said here, the only information I have) is that you will do things only if they are directly beneficial to you. Is that any more moral or responsible than the politicians you so strongly criticise?

Well that's not true for starters. There are plenty of people who may not like what's coming but will nevertheless vote for a sane response. If you have no morals then yes. Is this what you advocate? If not what do you advocate (that is actually realistic?). It's easy to attack, much more difficult to come up with a plan that is true, workable and saleable to suffient people to get elected. What's yours?

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