JamesPa

Ohh .. I remember having to do that - convince my time served boss that he needed to change work practices. Various occasions come to mind, but most memorably the novel idea that staff (in a technology company!) should be offered computers so that they didn't have to write long articles out by hand (and literally 'cut' and 'paste' when they wanted to revise), all for a secretary to type. It probably didn't help that he was in a relationship with the secretary!

To halve the price of electricity would, at present, require taxpayer subsidy @JohnMo - it doesn't remove the subsidy it just shifts it. And where is the evidence that our electricity prices are 'the most expensive in Europe', thats certainly not the case if you believe Eurostat. @marshian is right. Why are we even talking about tolerating unnecessarily poor installations when its SO simple, in most cases, to do it right: NO system separation, RIGHT size, design for 45C or less, NO external controls other than TRVs in the bedrooms if you insist (with, if you wish, Homely/Havenwise or the like specifically designed for heat pumps), adjust the WC properly = SCOP 4, job done! If you also tell the homeowner to get a sensible tariff, they will likely be quids in. Surely we aren't going to use the fact that we totally messed up condensing boilers as an excuse to mess up heat pumps (and then deflect the blame from industry failings to the government), or are some parts of the the industry (I say some parts because there are clearly a fair few good installers out there) really that piss-poor, that lacking in conscience and that unable to learn from its own mistakes? If the MCS closed shop cant make it happen right, scrap them and let competition sort it out. I do agree that a readjustment of gas vs electricity prices is needed, but please lets not use that as an excuse to tolerate continued industry incompetence. Time for the industry and its acolytes to cut the crap excuses and get its house in order. Early mistakes are excusable but domestic heat pumps have now been around for long enough for the 'professionals' to work out what to do, so JFDI or get out.

Im presuming this comment is intended to be funny and/or a poke at incompetent installers, in which case well said. If not then i must apologise that i dont understand it, so perhaps you could clarify?

Definite no here. Having just retrofitted an ASHP to my 1930s house there is no way I would bother with gas in a new build. Its cheaper to run by about 20%, much more comfortable (because there are fewer thermal gradients due to the way it works) and can do cooling as well as heating. Whats not to like? Incidentally, ignore the people who falsely claim that hydrogen heating is the way forward. Hydrogen does have a place but not for domestic heating, its for applications where there isnt an alternative. There is a very simple reason for this - to be green (which is the argument for swapping to it in the first place) it has to be made from electricity, and this is a factor of 3 less efficient than a heat pump, so is guaranteed to cost much more. 'Hydrogen ready' is just filibustering by vested interests in the oil industry so they can continue to sell gas boilers.

My suspicion is that the architect isn't confident about designing an ASHP based heating system so has taken the easy route out. BTW I have encountered more than one 'M&E consultant' that is similarly clueless. @johnmo is spot on the money with his comments above. Having retrofitted an ASHP to my 1930s house (solid walls, with partial fabric upgrades, good loft insulation, uninsulated floors, 200 sq m, 7kW loss) there is absolutely no way on earth I would fit a gas boiler if I were doing a new build, and I would frankly be reluctant to go back to a gas boiler if I were purchasing another 'second-hand' house. Get an ASHP design right (basically follow the principles set out above and size it correctly), and you wont regret it. Consider also if you want light cooling, an added bonus with the correct emitters.

@Dillsue thanks for the comments. It's going to take a few more read throughs before I respond with any confidence. In fairness to the people drawing up the regs they seem to be trying really hard to allow as much flexibility as possible without compromising the integrity of the initial FIT scheme. It does make me wonder whether they should just offer a buy out option, basically (eg) 90 pc of the remaining expected fit revenues in return for no ongoing commitments on either side. I can however understand why this would create all sorts of complications given that it's government sponsored. This does also highlight how complex 25 year contracts are in a landscape where the technology is forever shifting! I genuinely don't envy the people constructing contracts with wind farms and nuclear power stations, with perhaps a 50+ year life expectancy. The only certainty is that whatever the context is now, it will be totally different by the time the half way point is reached (even without the politics)

Hmm, interesting (and thank you). This is a later version of the guidance than the one I have previously read, and does indeed seem to omit many references to MCS. However the requirement to pro-rate based on total installed capacity seems to depend on the definition of the latter, which is apparently given on Page 65 in a way that involves certification by either MCS or Roofit. I think this might mean that you can install a DC coupled battery without MCS (because, although the metering requirements will change, the TIC doesn't) but you cannot increase the solar export capacity without MCS (because the TIC does change). If so that would, in itself, be very helpful. I may need to read this document a few more times to understand whether swapping an inverter (which, practically speaking, potentially changes the TIC) does (in terms of the rules) change the TIC in the circumstance that the inverter has the same limit (eg G98). Am I right in thinking (as I did with the previous version of the guidance) that there is nothing to stop you increasing the capacity of the panels above the output capacity of the inverter, and thus claiming FIT on the generation as clipped by the inverter (even though this will be greater in aggregate than the generation with the original panel capacity), on the grounds that the 'total installed capacity' is set by the inverter limit. Complex this stuff!

Have you got the figures to support that statement(either half) or are your assertions just speculation or a repeat of something that some journalist claims, also without evidence. Do you know how we compare with other countries with similar levels of public services? As regards the first part of your assertion (for which these is some evidence, albeit only by a tiny margin and even that dependent on whether you believe the Office of National Statistics or the Organisation of Economic Cooperation and Development), do you think by any chance that it might have anything to do with an ageing population and thus a reduction in the proportion working (state pensions count as benefits and are paid for out of current taxation not historical) . What do you suggest we do about that (which, btw, is predicted to get worse), other than the obvious which is to encourage a higher level of immigration?

@dilsue @mk1_man thanks for those very helpful comments which I will certainly factor into my personal choice. Im thinking that if I self install (unless I self install it definitely doesnt cost in.) I cant DC couple, because to DC couple requires changing the generation meter and inverter on the existing PV and that requires MCS to retain FiT payments. However DC coupling and a hybrid inverter means that one inverter controls the export so it can remain within G98. But if I AC couple, which means I can leave the existing PV alone and thus potentially self install, I need G99 unless I can find a certified way to link the PV inverter and the battery inverter to ensure that, together they, remain within the G98 export limit (even though in practice they certainly will). I wonder if any battery inverter supports that. Alternatively I can wait until the solar inverter fails and I am forced to replace anyway. They were guaranteed for only 10 years but mine is still going strong, I wonder what the practical lifetime is in the real world.

I can easily believe that this case with zero export payment. My current leccy prices are basically 7p from midnight-7am, 26p from 7am-midnight and 15p export. Since the night time import rate <daytime export rate, I charge my EV, do my washing, breadmaking, washing up and water heating at night, and don't worry if I export during the day. I don't currently bother with 'setting forward' my ASHP to benefit from the night rate, but neither do I set it back; bedrooms are just set to be a couple of degrees colder by adjusting the LSVs. For me at current electricity prices batteries would need to be <<£250/kWh installed to make sense, currently they are closer (at least in the South of England) to £400-£500.; In a few months time I will have years worth of daily records of peak rather and night rate usage, which will enable me to d a more accurate calculation, but I can already tell that its not going to justify a 'professionally' installed battery just yet, but I am keeping my eye on self install prices. One complication is that with solar already present any export by a separate battery inverter puts me into G99 territory. Currently I have no realistic option other than to AC couple, given that I get FIT - ie generation - payments as well as export payments.

I agree entirely. That's one reason I haven't bothered with a battery, with current tarrifs it makes no sense for me and I can't predict future tariffs. Only if either batteries come down significantly in price or the gap between export and import prices widens significantly (and looks to remain wide) can I justify this particular investment. Furthermore I wouldn't be surprised if, by the time that happens (battery prices don't seem to be falling that fast!), getting a cheap leaf with bidirectional charger turns out to be a great second car solution. Obviously the numbers vary from person to person.

I installed solar panels over 14 years ago. If I were installing panels now I would Fit as much panel capacity as the roof will take - as others have said you can have greater capacity than the max output capacity of the inverter. My only regret about what I did 14 years ago is I could have had more panels, and of course I cant now match the panel design Limit export to the G98 value (16A/3.6kW) per phase for simplicity. You arent going to exceed this very often (never if you have 3 phase) Get a decent export tariff (eg I get 15p/kWh for export with EON, Octopus do similar) Use DHW (ie a solar diverter) as the only on-site storage... ...unless you have an EV which is frequently at home during the day, in which case then rigging up a simple 'divert to EV if export > (say) 1.5kW' is worth considering - I did this for a while with a granny charger, Home assistant and a Shelley relay, but now don't bother as I have a night time import tariff that is less than my export tariff, so its easier just to charge on import at night. I would probably fit a hybrid inverter however, ie one that enabled (DC coupled) batteries to be added later, but I wouldn't bother with the batteries until they get a lot cheaper. With a decent export tariff you have to worry less about self consumption, so managing the use becomes easier, and the business case* for batteries more or less vanishes (at least for my usage pattern). Of course export tariffs may reduce with time, but then the case for a battery will be stronger (and batteries anyway cheaper) hence why I would consider fitting a hybrid inverter now. Modelling accurately in the real world house is rather difficult, so simplifying the question may help. ----- *Unlike solar or an ASHP, the environmental case for batteries is at best arguable, possibly non existent, so my current personal take is that they need to justify themselves financially.

The rads all fit comfortably under the windows (with a gap either side for curtains) and are either type 21 or type 22. There are just two exceptions: I fitted a type 33 by mistake, at a point in an extended process when I thought the heat loss was much bigger than it actually is. 22 or 21 would have done. I have one fancoil where a sensible sized rad just wouldn't fit. As I say my only regret is not fitting a couple more, just because of the fact you can use them for cooling. You can indeed mix down for UFH but from an efficiency point of view it means you are running your ASHP at the higher temp demanded by the rads, so if you are going to do this rads may be no less efficient. Of course UFH has its own advantages. Yes you can. After some experimentation I now do that in one bedroom only (used as a guest room) but not the others. The others are simply 'balanced' down on the LSVs to a slightly lower temperature 24*7. The best controls, particularly for an ASHP, are simple controls, and the low and slow mode from ASHP (or UFH) anyway facilitates and works best with simple controls; low temperature heating has a significant element of self regulation (if the room warms up the output of the emitters decreases and vice versa). I also get significant solar gain. The room with the most solar gain has the fancoil, so it simply switches itself off. All but one of the other rooms is run with TRVs disabled, ie permanently on (they remain fitted to the rads for aesthetic reasons!). I did a bit of balancing on the LSVs, but but rooms share heat much more than the manufacturers of fancy controls like us to believe Most of the year I run on pure weather compensation with no room influence at all, In April, when solar gain became significant in comparison to the base heat demand, I switched to what Vaillant call 'expanded' mode, which basically turns the ASHP off altogether when the room in which the room sensor is located gets more than about half a degree above the set temperature. I will switch back once the heating season restarts. So essentially its left on pure Weather compensation for most of t he year, with TRVs inactive. The result is much more stable than I ever achieved with the fancy controls and a gas boiler, and without the fiddling previously needed. The key is that the fabric heats up properly and serves to moderate any temperature variations. The house is 1930s 200sqm, originally with solid walls. IWI and a couple of modern extensions mean that the walls are now ~80% insulated, but 20% remain solid. Double glazing and 300mm loft insulation completes the picture. Floors (a mix of suspended and concrete) are uninsulated. 7kW loss, Vaillant '7kW' heat pump. Why did it work well? No system separation (ie no buffer tank, plate heat exchanger or low loss header between ASHP and emitters) ASHP capacity correctly matched to house loss Design for a reasonably but not excessively low flow temperature - radiators have to fit!, simple controls ie the controls native to the ASHP only Operate 24*7 choose a sensible tarrif (in my case essentially economy 7 ie 7 hrs cheap leccy in return for about a 10% uplift during the day. ie Nothing 'clever', just keep it simple but sensible. I could probably do a bit better still if I operated a 'set forward' at night to take better advantage of the cheap night-time leccy, but I cant currently be bothered!

You should question that assumption. Obviously it depends on the achievable rad size. I sized my rads for ft45C at the design temp of -2 , am actually running at ft42C with an ashp which is costing roughly 20% less like for like than my gas boiler. None of the rads are intrusive in any way. The house, now heated throughout 24*7, has never been more comfortable. Even I have been surprised. My only regret is not adding a couple more fancoils (I fitted just 1 where it was absolutely impossible to fit a sensible size passive radiator). They are great for light cooling.

@johnmo thanks for flagging this. So its a plate heat exchanger built into a plinth, especially designed to increase householder running costs by perhaps ~15% - 30%, targeted at those least able to afford it and institutional specifiers who haven't got a scooby. The voiceover to the ad is worth listening to for a laugh. Apparently the device also means that radiators will not need replacing (in a parallel universe presumably, where the laws of thermodynamics don't apply) Isn't free market capitalism wonderful!

You can appeal (to the planning inspector) against refusal of an LD certificate, but of course this is only worth doing if if you actually meet the rules! The rules for PD are strictly applied, there is no wiggle room, if you cant meet them then you need to submit a full application. Note that its not actually necessary to get an LD certificate, you can proceed anyway if the PD rules are met, but of course there is some risk in doing so if there is any ambiguity. Full applications are judged against your LPAs local plan not PD rules*. If you decide to go down the full planning route best make sure you know what the Local Plan says in relation to heat pumps and related things like noise, visual amenity etc; basically you need to demonstrate compliance with any relevant policies and its generally best to address this directly (ie for each relevant policy set out why you comply). Some LPAs make you submit a full professional noise assessment for domestic heat pump installations. If the LPA is advising that you try to use PD it might suggest that they are one of the awkward ones (mine was extremely awkward, but it got better immediately following my successful appeal). *although if you can demonstrate that a more harmful development could be carried out under PD then you have a case for getting full permission even if your development is not compliant with the Local Plan. This is known as the principle of fallback see eg Mansell v Tonbridge And Malling Borough Council [2017] EWCA Civ 1314

PD rules do apply in conservation areas (in England and Wales - I dont know about Scotland/NI) unless either 1. The specific rule in question excludes conservation areas or 2. The LPA has made an article 4 direction removing them In the specific case of ASHPs its clear that the specific rule in question does not exclude conservation areas because of the presence of clauses G2J and G2K. The LPA can still make an article 4 direction though; I don't know if OPs LPA has made such a direction.

You have three options: (I'm assuming this is England/Wales and that the refusal was in response to a full planning application not an application for a certificate of lawful development.) 1) submit a revised proposal to your local planning authority (lpa) 2) appeal to the planning inspector 3) amend the proposal so that it falls entirely within pd rules. 1 or 2 will need to argue that it is in conformance with the local plan, IE the development plan made by your lpa. The reference to schedule 2G2 is a bit spurious in a way because in the case of an express application it's the local plan that counts not pd rules. I say in a way, because one appeal argument (which I used in my appeal) is that a more harmful development would be permitted under pd rules, and the lpa will be mindful of this argument. You could try to talk to a planning officer about (1) to see if they would be receptive, but there is no guarantee that they will be helpful. Route 2 is independent of your lpa, it typically takes about 18-24 weeks. Planning inspectors are often more logical than lpa officers. Route 3 is the easiest and as @johnmo says the rules for pd have recently been relaxed. I ended up doing (1), following advice from a planning officer and then, when they reneiged on the advice, (2). The appeal was successful. Appeals are free of charge.

Personally I wouldn't get too concerned about it, unless of course someone visits the house who would have difficulty accessing it. It's only two screws. TBH mine just sits loose on a shelf in an inner hallway which is a fairly neutral space in terms of house temperature.

I've heard worse, and it could have been much worse, but its not going to win the 'Top of the SCOPS' award! Three months take us back to March. Over 4 would be a reasonable expectation at this time of year depending on your operating temperatures and how Daikin arrange their trade offs, so there is very likely improvement to be had. For comparison my 7kW Vaillant, operating at ft 42C at design OAT of -2, reports 4.2, 4.7, 4.7 respectively for Mar, April and May. 8m in the South of England.

Good plan. If you could get it to be instalked as designed ie a volumiser (not buffer tank) and the 6kW (or even the 8kW) model, that would be a excellent advance. All the secondary pumps will need to go as a consequence and they should balance the zones on the zone control valves. Most (not all) domestic heat pump installations should be run 24x7 as a single zone without buffer tank, a correctly or only modestly oversized heat pump, with no or minimal controls other than the heat pump native controller, and any room thermostat used only as a temperature limiter not a temperature controller. Weather compensation should be adjusted to the lowest possible operating temperature consistent with heating the house. It's pretty much the polar opposite of how we typically operate boilers in the uk and some installers just don't 'get it'. Unfortunately the industry has got out of the habit of designing systems over the past decades, preferring instead to overspecify everything and let the controls sort it out (to the detriment of the consumer in terms of running cost and comfort). Heat pumps aren't so tolerant so now installers have to do it right, some are lagging!

Red flags here. The 9kW unit is actually (sofaik) the 16kW software derated, whereas the 6kW is the 8kW derated. Given this there is absolutely no way should he have fitted the 9kW. The fluff about lower temperature is Bow Locks. The temperature you operate at is determined principally by the size of emitters not the heat pump. Given this I'm not surprised he fitted a buffer tank, which is almost always technically unnecessary (and frequently compromises performance) in a domestic environment. Taking all this together you are, I am sorry to say, quite possibly paying 30% more for your heating than you need to. Is there any prospect of getting them back to do the job properly, it's notoriously difficult as MCS is designed to protect installers not consumers, but some others have had a success. If you have records of consumption/heat delivered you may be able to prove it's oversized. Since they know they supplied the wrong one that may be a starting point for a claim that it's unfit for purpose. Daikin, unfortunately, don't make it easy to access detailed technical data on performance Vs load (or indeed anything else), which will make it difficult for you to prove detriment. What sort of COP/SCOP are you getting? I think a step back from the immediate problem and a quick exploration of these matters might be a good course of action. You may well conclude that nothing else can be done, but it might also be silly to do something before thinking it all through. Is the system diagram you posted the actual one as installed (and if so where is the buffer tank - BT3 is shown as a 2 port volumiser but your photos appear to confirm there is a 4 port buffer present), or did the plumber do something different to what was designed for some spurious reason? What's the rationale behind 4 zones?

As it happens I agree with the visual and practical cautions mentioned above. It's odd though. Commercial Aircon units are very commonly mounted several metres up on walls and also on flat roofs. Maintainers seem somehow to manage.

It might depend on what is the other side of the boundary as there are also conditions in the legislation about siting so as to minimise the effect on the amenity of the area. Best check the full wording in the original legislation and the amendment order Eventually amendments to legislation generally get consolidated back online into the original so you only have to read one document, but that has not yet happened with this particular amendment as it is not in force until 29th May.

Just to add to the above, the pressure registered on the gauge may be different, when the pump is running, to the pressure registered by the heat pump due to dynamic resistance in the system. If the difference slowly increases it might indicate that the magnetic filter needs clearing.