markocosic

Nope. Most run the compressors flat out for DHW production and the compressors on a good unit are very much louder than the fans I'm afraid. Windows are likely to be closed and blinds pulled whilst cooling if PV powered. Nighttime cooking is the swine for those without cooling as their windows will be open for night cooling.

Any reason not to use Pe-Al-Pe (not Pex-Al-Pex) for low temperature heating? (<55C, <6 bar) I ask because pish cheap on offer at ~£0.34 inc VAT just now. (the white 80C rated stuff next to it is spendier) It's aluminium sandwich 5 layer stuff so should be airtight just the temperature rating differs right?

I don't believe the zero rating for VAT requires MCS. It's only the planning and the grant funding gravy that MCS controls. That and export payments for PV. (it isn't a requirement that they ask for an MCS ticket but all the energy companies ask for an MCS ticket) I don't think zero rating the VAT on supply of heat pumps is needed / enough for the unregistered plumbers. You actually get to zero rate the lot (heat pump, cylinder, pipework, wires, radiators replaced - all the ancillaries too - including the labour) which there's no practical way to allow them an exemption for if they're buying these and they're not themselves VAT registered. If they're serious they'll setup a Ltd company, register for VAT then do nowt but heat pumps through that company so that they can reclaim all the VAT whilst charging zero on the installations including ancillaries and labour. Whilst keeping the sole trader below VAT threshold wheeze going for non heat pump work no doubt.

That is indeed the current bathroom.

Absolutely Somebody not giving me what I want? Clearly that person is my enemy/oppositon. Something too expensive? Clearly that person needs to be made to charge less. etc Supply. Demand. Prices fall if you increase the supply of trades people. Price. Profit. Cost. Value. Prices fall without sacrificing profits or quality if you remove the non-value-adding costs. Their own time is the biggest avoidable cost for trades people. Dead end sales efforts; doing automate-able tasks manually; wading through pointless paperwork; risking callbacks for things that aren't your fault etc. You don't ask Elon to re-use the tyres and the floor mats from your old diesel VW. You wouldn't buy a new set of tyres and floor mats just before you're due to replace it either. Apply the same to the house?

Fair point. I think "Whose interest is in to do more work and accept more risk for less money?" is probably fairer.

You're cherry picking one line from a more comprehensive explanation of why capitalism is relevant here. And unpaid design time. Uncosted risks etc. "Whose interest is in to do more work and accept more risk for less money?" Not all. Yours. Not theirs. Absolutely unrealistic to expect otherwise and plans that rely on this are doomed to fail.

Absolutely it isn't. It's been around for years. It comes built into the standard controls. Along with load compensation for those times when a purely temperature based curve isn't appropriate due to solar gains / internal gains. If your heat pump is a heat pump designed by a heating company that is. (as opposed to an air conditioning firm with little experience of hydronic heating) e.g. Buy the Vaillant package with the standard controls. Put them somewhere that they sense the air temperature and don't get hit by sun / draughts. Enable the adaptive heat curve? It is absolutely not rocket science if one can RTFM. Even my old VRC470 (controlling an old Ecotec 824 combi) has this adaptive heat curve function. Don't try using it with time clock heating control though. Or auto learning a curve un summer / spring / autumn. 😉 And if you've actually done the sizing calcs to check what your radiators can do then you'll of course already know (well enough) what the curve should be and can largely leave it to the manually set curve plus load compensation to choose an appropriate flow temperature. Not a barrier to deployment.

I've never tried to soundproof a bathroom; nor been somewhere that the bathroom is soundproof. Any practical examples? Experience of this working?

Not that I'm aware of. The only unit I know that ONLY has two inputs (call for CH, call for DHW) is the Kensa ground source unit designed for social housing applications. They consider both the landlord and the tenant as completely unteachable and insistent on using on/off controls irrespective of the impact this has on operating cost. So produce a unit that literally only has two calls for heat and naff lifetime operating costs to match. Else they all come with controls capable of being of operated more efficiently than that. Even the cheapie cheapies such as Phinx (available to anybody FOB China by the container full) https://www.phnix-e.com/r290-greentherm-heat-pump.html If rads you're certainly weather compensating those. If UFH you're probably weather compensating that and piping to it direct; though it's less critical. And you just just bang 65C hot water into a cylinder if you don't need it either. You do dT control between the hot water cylinder contents and the flow temperature to it. You can make most of the more capable controls operate the way that you describe if you're particularly bloody minded though so it shouldn't be a constraint on your search. Pana / Mitsi / LG / Samsung ave all announced R290 units but they don't have good availability yet FWIW. They'll be busy selling off all the old F-Gas stock whilst demand (for anything) is high before they start offering R290 units I suspect. I think Nibe and Vaillant the only R290 units on lots of UK shelves.

We're definitely keeping the spade and the forest! One bathroom @ProDave Not allowed to build another cabin until the first is finished...

"Why on earth would you want a LOUD extractor fan?" "Oh." SWMBO doesn't like the rest of the world to know how big the poo was by the sound it makes. I will be wring in a "poo switch" that makes it easy to boost the MVHR for 5 minutes. She would like a "poo switch" that provides sound to mask the poo. Are there products for this already? Speakers for houses / bathrooms that allow you to listen to tunes soaking in the bath AND could be wired to a button for them to play whilst the poo happens?

The designers need to have a clue. The designers gain a clue by doing the job before they move into design. Per response above I expect the higher calibre installers of today to rapidly move into desk jockey roles, supervising and directing an army of their classmates, within a decade of their starting out. It's daft to invest in training the bottom of the hierarchy and expect them to be in a position to teach others. They'll be following instructions their entire lives. Best case you're training one person. It's equally daft to invest in training princesses sat in ivory towers and expect them to have a clue what a pipe looks like in the real world. e.g. Octopus Energy software princesses managing to do three surveys and arranging for the equipment to be delivered only for their subcontracted installed to exclaim "FFS did you even measure the size of the cupboard vs this cylinder; and FFS did you not think this old hose with a one-pipe gravity system might need a repipe or were you too busy reading from your magic app that said no microbore, check, therefore all is good; etc" You learn this stuff with grit under your nails and the skin of your knuckles left under a floorboard somewhere.

How difficult do you think "plumbing and electrics" are? If the job pays the wage to attract folks of the right calibre they're up to speed on all they need to know to survey/design/install within 6 months / within the first season. A year at worst. Say they're 20 now because they left school at 18 rather than 16 and spent a year enjoying casual work before deciding that they'd like real money. The next five years are working out how to make money by doing the jobs quicker. A job every fortnight for £5k profit a fortnight rather than a job every month for £2.5k profit a month. They're now 25 and on six figures by working their backsides off. The next five to ten years are working out how to train their labouring minded schoolmates up to do the site work; to train their estate agent minded schoolmates up to go out and sell; and move away from the tools onto a desk / working out how to scale the business by the time they're 35. They have to do this as the margins trend towards £1-2k per install. And by the time they retire and it's like for like swaps of heat pumps the margins will be peanuts but that's ok because they're experts in the everyday business operations / processes. Why do I think the majority of boiler bashers are wholly unsuitable? Training stubborn know-it-all 50 year olds / motivating comfortable have-it-all 50 year olds who fit gas boilers to do anything different isn't a lost cause but it's a lousy use of resources. They're difficult. They're not motivated. There's no way they'll start out on £30k today with the potential to make £100k in a few years by working hard because they make far more than that now and they don't intend to work hard later. Mainly they think they know everything though. Training low-calibre folks that just about how to drive a van that says British Gas on the side and service gas boilers to fit heat pumps is also a lousy use of resources. Partly because they probably can't. Partly because that initial investment doesn't compound because they're not capable of growing a business off the back of it. Many of those who work for this type of firm today were hired because their employer knows they're incapable of leaving. Not capable or motivated enough to go out and run their own firm. Invest the minimum possible amount in a marginally capable employee fairly safe in the knowledge that they'll stick in the job for life.

Absolutely. If they're not it's easy to swap single panel for double panel in man situations. Hackjob properties are your main issue. Anything that's been extended is invariably bodged. If it's a virgin Barratt build from the 80s that's have caivty beads, or an ex council house that's unmolested other than the conversion from a coal fire to gas central heating, and then double glazed lot insulated and cavity blown, you're probably good to go

1) Attract higher calibre, numerate / literate folks into the industry by paying good money and eliminating the bovine excrement. (having to compete with fly-by-nights; having to waste time chasing/qualifying leads and completing non value add tasks) You don't actually want this job to be a low paid job just right now. It should be very possible/common to make six figures aged 25 to get the people you need fully bought in. Drop the rates later once they're hooked. In this respect it's a good idea to let te folks willing to pay £10k pay £10k right now. 2) Kill the MCS stranglehold. That eliminates the fly-by-night grant chasers AND a good chunk of non value add tasks. You keep the requirements (e.g. the technical requirements with regards noise for permitted development) but make it the job of planners to enforce planning conditions (e.g. please prove it's adequately quiet, where here are the requirements lifted from the old MCS standards, and if you meet them them it's deemed fine, but you don't need to partake in the rest of the MCS charade) Relax a few planning conditions too. They're asking for units to be too small. It should be permissible to have both a heat pump and an air conditioner. There shouldn't be stupid restrictions on siting R290 propane units near to doorways whilst it's still ok to keep two 15 kg propane cylinders inside your house. Also 3) Look at communal ground arrays / hybrid arrays (substation gets a low temp air source heat pump on top that tops up a ground loop which nearby houses rent access to for £X per year and chuck a shoebox water:water heat pump in the kitchen to drawn from and feed the existing heating system; laying your LV cable reinforcement and FTTP at the same time as you lay the ground loop) 4) Quit subsidising new natural gas connections and subsidising marginal gas supply costs by moving the carbon taxes from electricity onto gas and moving the welfare taxes from electricity to central government and by requiring price transparency on the bills. (distribution and metering cost more than the electricity; historically) 5) Make use of / abuse advertising standards privileges / editorial accuracy requirements to kill the hydrogen nonsense; to kill the hit job articles; etc. 6) Take a chill pill. AC in cars is ubiquitous. Let people do AC in houses more easily. Don't mandate that in order to receive grant funding the heat pump must deliver heat AND hot water. Chop the available grant to £1k and apply the condition that it's a packaged/tested solution with a sCOP of 5 or above. It's pish easy to install A2A units in this ball park. They work. People will rave about them. Advertise the damn things on the side of city buses. I look at trolleybuses here in Vilnius (you know; those nuclear/solar/wind/hydro powered items of transportation that spank anything other than shoes and a bicycle on energy efficiency; have sweet fudge all reliance on Chinese batteries; and have been around in volume from Newcastle to San Francisco since the mid 20th century) advertising heat pumps and triple glazing to the general public and bang my head on the wall at the defeatist, stuck in the past, somebody else's duty to help me attitude that the UK has developed. Pictures of buses because they illustrate how chuffing dumb/immoral the folks who have the power to be benevolent dictators but choose to lick the backsides of Musk, Xi, Putin et al rather than getting on with doing anything are in the UK. See also PV diverters and house batteries. Dumbest not-even-zero-sum investment ever for UK plc.

Already happening. The firms that use that as an initial assessment/final sanity check also do more detailed designs though.

Do you live in the same capitalist world as the rest of us? Yes? Then this is stupidly simple. Say there are 20 jobs available. Say 10 are "give me a complete new system" and take moments to price up; and involve plenty of work for which you charge. Say 10 are "tell me everything there is to know about heat pumps and work out how to reuse all my existing stuff" and take far longer to price up; and involves more unpaid work upfront; potentially more unpaid work later; and less work for which you can actually charge. I say this because those latter 10 are customers who are paid PAYE; haven't had to work out the true cost of doing work in recent living memory; and cannot comprehend that all the time you spend selling / marketing / designing / quoting / revisiting has a cost associated with it. Say there are 10 installers. They are not paid PAYE regardless of whether what they're doing is value-adding or not. They do not exist to serve you at their own expense. They're going to go for the first 10 jobs. Cost is no object. It's whatever you can get away with charging subject to perceived value by the customer. The latter 10 simply don't happen Say there are 20 installers. There'll be some competition. The first 10 will pay a market limited rate for the complete installs. The latter 10 will pay a reduced cost for less work PLUS the cost of all the other nonsense that they think is free. It'll probably not be far off the cost of the first 10 if you're good at knocking out the exact same thing time and time again; and certainly not on a lifecycle basis if there's any compromise in the performance that results. Solutions for reducing sales/marketing costs (acquiring and qualifying leads - i.e. weeding out the time waster customers) and automating surveying/design and procuring standardised packages in volume will reduce costs for all; but disproportionately so for those knocking out full packages. Say there are 30 installers. The market rates drop to the point that the more capable ones quit the industry in favour of something that pays better. You're left with the only just competent enough to keep the lights on crowd. Case study: your average domestic gas fitter; now that those who trained in the 70s and 80s have died? In answer to your query what you need...is enough supply for it to be remotely worth effort of somebdoy even considering taking on the crappier jobs. Everything else is more of a symptom than a root cause. MCS, which puts up barriers to entry whilst doing literally zero to ensure compliance with any kind of standard, results in what is in effect a government sanctioned / government subsidised union. Opposite of what you're after here. Dumb controls are a dumb idea. Products whose consumer facing controls suck less are a great idea. See also products designed to reduce installation costs. Include the fill loop. Include the filter. Include the pump. The expansion vessel. The controls etc. Manufacture of a turnkey box rather than a pallet of bits. That'll come as local volumes become...less artisan.

Taps are not really a risk. Only the shower can produce aerosols. Cold water from tanks in summer is riskier then hot water. People don't die. If your tank is new (sorry haven't kept track) then fire away heating to 50C. Just don't breathe in any lukewarm water from the cold pipework.

Firms that add automation in lead/project management and surveying/design; perhaps also supply chain financing clout; to your average plumber. For a fee to the plumber that's well worth it. https://lun.energy/ https://techcrunch.com/2023/03/22/lun-seed/ https://skoon.energy/ https://www.heatgeek.com/ https://www.thermondo.de/ etc Busy space. Lots of the task is automateable. It still relies on local trades and an element of judgement/gut feel though. These firms are targeting those trades. Augmenting them with software tools to work faster. Separately OVO, E.ON, British Gas, Octopus et al are seeking to dumb the process down so completely that a full time employed chimpanzee can do the retrofit. Both of these will be where standardised approaches come from. The MCS will not achieve it BUT until such a time as government stops making singing from their hymn sheet part a condition for £5k an installation they'll continue with a compliance scheme with which compliance is optional and installs that are a lucky dip box of frogs.

The shower valve and pipe are purged at relatively high velocities and scoured of boifilms. Cylinders are not. 60C heating (at the 1/3rd mark) is for quickly pasteurising the gunky water at the bottom of the cylinder. It's never 60C at the base of old cylinders. Guidance that refers to this is bunk. Impossible in practice for most designs. It's more like setpoint 60C using a reheat stat 1/3rd of the way up. New unvented cylinder with a big coil that runs to the base is fine at 50C. Old junk ought to get junked along with the boiler and replaced with something clean with an appropriate coil in it and low standing losses etc IMO. Cylinder replacement ahead of boiler replacement is not problematic.

Safe to say the datasheet didn't set your pants on fire then @sharpener? 😂 It's cheaper than fish and chips. The upfront saving by fitting one of these isn't worth it if you intend to be the on paying the bills later though. From which you can deduce that any other advice from this company is not going to be in your best interests either. You really don't want to be pushing these units much above 50C flow temp if you're the one paying the bills; and max output is indeed 12.5 kW at A-2/W50. Minimum output of 7 kW @ A7W35 may be tolerable without a volumiser / header arrangement IF your system is sufficiently open. Your having them "on at different times" is a red flag for that though. Setup something like the attached to see what the output of the various zones and the flowrates that would result are? IIRC MCS won't allow the design temp to be changed but you can change the ventilation assumptions and operative room temperature assumptions if you like. I'd be looking for an installer giving some consideration to the operating cost though. Unless feeding UFH only (and with large space heat load relative to hot water load) you'll not do too well with an inflexible low temp heat pump. Knoll Pipe Calcs.xlsx

Thanks!

Link to the hob? I'm interested in low power hobs and those with current limiters for renovating apartments with flaky power supplies

Agree. Insulate heat source primaries up to the dhw cylinder; and perhaps the key dhw runs that are always/often hot; and maybe the exposed cold water runs in bathrooms for anti condensation purposes; but ignore the rest and year then as free heat emitter upgrades.