markocosic

Why do you say that the COP for hot water is lower @Iceverge? You're lifting from incoming at 10-20C up to 45C. (or should be) The COP lifting from 10-20 will be stonking. The COP from 35-45 less so. The energy weighted COP should be well over 3 though - unless there's a stuffup with how it's implemented. This chap knows what he's doing for example. Summertime COP averaging out at 4.7 for ASHPs doing pure hot water preparation. (Initial COP reheating from cold (19 external 32 delivery to tank) was just north of 10. Big coils or loading via plate heat exchanger in "fully stirred reactor" heating mode (heat up the whole tank gradually) not "fully plug flow" heating mode. (what mixergy tanks do and how phase change units like sunamp behave) Discharge should always be plug flow. Delta capital for dedicated all in one heat pump tank vs unvented tank is probably <£1k. Obviously doesn't apply if replacing what you already have.

This kind l kind of thing? 😉 https://www.linkedin.com/posts/markocosic_too-many-people-think-that-gas-boilers-cost-activity-6970379299598045184-i81G?utm_source=share&utm_medium=member_android There are still two sets of three of those heat meters available for those interested in monitoring the actual performance of boilers or ashps feeding cylinders. Viewing the summer daily gas use on octopus also works just fine. Boiler Cost.xlsx

Happy days 🙂

It's a glorified fridge @Tom No servicing (above any other G3 cylinder) beyond occasionally clearing out the spiders. No need for immersion either unless your usage pattern is ridiculous. There's a 270L version too but 200 should be plenty. A 12 kW array will probably be flat out in winter just doing your household electrical load. (assuming you're battery shifting the night load) what is your projected generation vs usage for Dec/Jan? Not much left for hot water and space heat. Say An A2A unit to get 300 kWh source heat out of generation 100 kWh. An A2W unit to get 300 kWh hot water out of generation 100 kWh. 100 kWh left over from that 12 kW array for the rest of your household load if you're lucky. Throwing an additional 8 kW array at the problem would get you 200 kWh more that you could waste via immersion heat / willis heat. Cost more than £5k probably £8-10k. Add £2.5k more for the extra cost of a sunamp Vs the heat pump cylinder. Or you don't waste the 200 kWh. Spend £2.5k less on the water heating and make that extra 8kW array 12 kW. Now 300 kWh leftover to roast turkey or sling in the EV. I just can't see any scenario where spending MORE to achieve a WORSE result (Sunamp) makes any sense whatsoever. Unless you're just obsessed with having a Sunamp?

If you'd actually clicked any of the links you'd have seen an "all in one box" designed for installing in a utility / garage / basement @Spacey73 Buy. Plug in. Finished. You don't even need to duct the vents if it's in a garage / basement; and it will even dehumidify the air as it makes hot water so that your tools / cars etc don't rust. Pretty. Freaking. Awesome. You then spend the £2.5k that you've saved by buying this instead of a Sunamp on more PV in the field. Or...if you would enjoy it more...buy yourself the shiny Sunamp that you want and enjoy wasting the PV that you could be using to heat your house or run your fridge instead. It's dumb but if the Sunamp is what makes you happy then do go buy one and I hope you enjoy looking at it and aren't too bothered by all the electricity it is wasting. Secondhand Electric Agas are also cheap on eBay at the moment if you fancy wasting some more electricity. 😉

Sounds like there's no reasoning with somebody who has decided to waste money doing things inefficiently. Enjoy wasting electricity to produce hot water that could have been used to provide hot water and space heating.

Why don't you get something that heats the water efficiently instead? Rather than dumping your previous winter time PV into an immersion heated Sunamp for "100%" efficiency whey don't you feed it into a heat pump cylinder for 200-300% efficiency? e.g. https://www.electricpoint.com/dimplex-edel-hot-water-cylinder-heat-pump-200l-edl200uk-630rf.html https://www.tesy.co.uk/heat-pump Higher performance. Lower cost. Winner.

IIRC they are also on a poor basic pay plus sizeable commission for punting things that the end customer doesn't need. Plausible deniability for Centrica that it's the rogue fitter at fault rather than their corporate policy to miss sell. If Martin Lewis hadn't turned so soft headed recently he would to after centrica for mis-selling of a financial product (insurance that was unlikely to pay out / not in the customer's best interests) as he did with payment protection insurance. Alas he's more interested in helping Liz Truss bankrupt the UK with broad brush price caps these days. (vs more generous but more limited/targeted support to avoid subsidising waste)

Sorry - thought everybody used "branded vans" as a reference to the chains full of trainees (the best you'll get from these folks), those so utterly useless they're unemployable elsewhere, and outright flipping crooks. Independents are usually great or bust with little inbetween IME. 🙂 My business partner's wife is the "don't touch anything yourself type" and wanted to call in Pimlico for a repeated loss of pressure much as Damon describes. Woman at home on her own so... Boiler.neers replacing as it's so old everything will leak if you try to dismantle it. Scaffolding needed to replace because 2nd floor flat. Managed to price a combi swap up to near five figures and f**ked off (after charging for the fallout and attempt to cheat the consumer) without even doing the courtesy of trapping so air in a rad so they could at least have a hot shower. Complete and utter scumbags in the British Gas mould. Advised them to find nearby gas safe bod that wasn't with a large company and had an Eastern European sounding name whilst they were still fuming. Said Igor charged to service the thing and told business partner to go toddle off to Screwfix and nail on an external expansion vessel himself until something important died. Needless to say he got the job to swap the thing 5 yrs later when it came time to sell the place and 'brand new boiler" added more value than it cost...

Nothing wrong with sign writing of they're an independent. 🙂 I've yet to come across a British Gas or Pimlico man who quotes with integrity though. At best trying to fleece pensioners and Londoners respectively by condemning boilers that just need repairing in order to drum up work. Does your experience differ? @Nickfromwales

My wife forks with these kind of finishes as an esty side hustle and ships most of them to the USA: https://www.etsy.com/uk/shop/MetallicDesignStudio?ref=simple-shop-header-name&listing_id=672140894 - Take a sound substrate (a wooden door would work; most of her sales are aluminium composite panels as the base canvas) - Keying and priming is straightforward (and then all materials behave the same way) - Applying the metallic base is tricky (metal particles in a binder of some kind) if you want to have texture - Aging the metal particles is an absolute black art (just how rusty is rusty; which acids applied using which methods give which colours) - You then need to run over the top with an appropriate varnish/lacquer to retain the finish (which of course changes all the colours) How much do you enjoy repetition? I'd say it took about two litres over three months to work out the basics; 12 months to be able to produce a particular colour / pattern finish first time most of the time. Most of the manufacturers are Italian (venetian plaster / marble effects being their main product lines) and visiting one of the trade shows is a good way to pick up application tips. She'd probably say "No job it too big. No fee is too small." 😂 Ask how much a plain door is. The "from £4.5k" leaves plenty of room for final finish...

Chimpanzee in a branded van? That'll be a bad replacement then...

Even easier @Nickfromwales Damon you can isolate the space heating there, drop some water out of the boiler service drain, and recharge the expansion vessel with a bicycle pump. I'd fill it to a slightly lower level as your system pressure when cold (e.g. 0.7 bar for 1 bar cold and 1.3 bar hot) so that when cold the rubber inside is slightly to one side of centre, and when hot it's slightly to the other side of centre. Take advice from an actual plumber though rather than the bodger perpetually recharging a slightly dog eared expansion vessel. 😉

Got a bicycle pump? Drop the water out of a radiator; refill the expansion vessel precharge; then refill the system. If the vessel were totally dead then as the system comes up to temperature the pressure would spike and it would pee out of the relief valve before dropping to zero. The fact it doesn't do that immediately says there's still some charge left even if it is leaking out slowly. If the leak is slow enough recharging it will keep it alive longer. A more ghetto option, assuming bottom entry and exit, is to crack the bleed valve on a radiator and then drain down air air bubble in the top of the radiator. Repeat in other rooms preferring the ones that you don't use much / need much heat. That'll keep the system running long enough to sell the house when it becomes an exercise for the next helpful soul that decided to bleed the radiators to fix. None of this gives you an excuse to bin the thing though. 😉

Floorplan?

You're in a similar pickle to me in when it comes on wanting to play but being mindful of moving on. The fabric is done for. There's no 5 year paybacks available. Everything you put into it will get wrecked. The gubbins are (trans)portable. Your PV, for example, will be coming with you. With that in mind... A £500 combi will probably outperform whatever you have now. Will that pay for itself in 5 years at £0.15/kWh and 3,000kWh/year? Probably not. Hot water? Hot water from a gas combi at 80% efficiency beats hot water from PV environmentally. How so? Every kWh of electricity exported will save about 2.5 kWh of marginal gas being burned at a power station. It is a fallacy to consider the mean grid carbon intensity when evaluating what difference your immediate behaviour makes. As such use of PV diversion and the Sunamp is interesting but environmentally irresponsible. Both are (trans)portable and (re)saleable durable assets though so can make it to a new house or somebody else's house should you wish. Only the install/uninstall costs are dead money. To do better than the combi heat you could: - preheat the feed to the combi with drainwater heat recovery (unlikely to be viable do to payback time, retrofit difficulty) - preheat the feed to the combi with solar thermal (in the event that your connection capacity is maxxed out and you've still got space for more sun, unlikely on any modest house) Else you're into heat pumps. I think this is possibly your scene. They spank running the combi. Relatively easy to bring with or resell after you're done experimenting. https://www.tesy.co.uk/heat-pump https://www.electricpoint.com/dimplex-edel-hot-water-cylinder-heat-pump-200l-edl200uk-630rf.html https://www.ariston.com/en-me/products/heat-pump-water-heaters/domestic/ https://gathering.tweakers.net/forum/list_messages/1941248 https://www.auer.fr/en/products/heat-pump-water-heaters/edel-water-heat-pump-water-heater/ The Sunamp is useless for heat pumps because it requires that all heat is delivered at the maximum possible temperature rather than ramping up as the cylinder heats. You couldn't do anything more inappropriate for heat pumps. Space heat? You've done what's reasonable for reducing consumption. Heat pump is next. I might try an air to air unit in a central location given your minimal heat loads and tolerance for minor discomfort. What's the COP on the Panasonic CU-VZ12SKE / CS-VZ12SKE combination that's sat on my wall? 3.7 kW output at -7C with a COP of 3.8 or 14 pence per kWh 2.25 kW output at +2C with a COP of 5.7 or 9.1 pence per kWh 1.45 kW output at +7C with a COP of 7.8 or 6.7 pence per kWh 0.9 kW output at +12C with a COP of 10 or 5.2 pence per kWh Those COPs spank the gas combi. So does the cost. Note I've used the previous price cap figures for a more accurate reflection of what energy actually costs rather than the "deposit" that we'll be paying today and ignoring the interest and repayment charges that come later courtesy of the government's latest insane plans to avoid the demand reduction that is required in the light of reduced supplies this winter. Comfort is not as good though. There will be some draughts. There will be some noise. The efficiency is up there though. Easy to unplug and bring with when the building is demolished. Close one valve, pump the gas back into the outdoor unit, shut the other valve and knock the power to the outdoor unit off, crimp the copper pipework then snip and reinstall with new copper pipework in the new location. Planners are unlikely to know the difference between a monobloc for space heat / hot water and an air to air unit that can heat/cool. Functionally they're identically obtrusive / noisy too so it doesn't make any odds. I wouldn't ask for consent. I have a vacuum pump and gauges that you're welcome to borrow if doing a naughty DIY install. Alternative? Single outdoor heat pump and a cylinder to suit. Possibly higher performance for hot water but will be lower performance for space hating unless you get very involved with radiator swaps. More disruptive to install. Fewer draughts. Less noise. -- M

This chap is fun for blueprints: https://www.mobile-solarpower.com/ Shame that those "camping kits" can't be made with just a little more intelligence to sit in the corner pretending to be a little enphase "hotel load shifter and backup" unit!

The standby usage also looks a little careless unless I'm misreading data sheets. Who else make equivalents?

An almost entirely UFH-ed build will be just fine on a heat pump; and if you're peaking at 35-40C input temperature (so can go lower when it's warmer) then sCOP will be excellent. Probably nearer 4 with a good unit and some attention to just how low flow temp can be set most of the time. If oil boiler not stuffed then install in parallel with changeover valves such that you can fall back to oil if required for stoopid cold or stoopid spendy electricity. This might also let you sit below the ~16 kW size where you are over 16A per phase and the DNO needs to be involved.

Sounds like an cluster fudge of a design. Do you have a schematic? If it has a "header" in it, or a buffer vessel with four pipes, then you COP will definitely be awful. Design fault. Do you have a thermostat? Then your COP will probably be awful. Design fault. Share the installation drawings and the control methodology with us? If you don't have this from the installer then you'll need to find a competent one to correct the.mess that the previous one has left you with. Note that Mitsubishi are sharks, along with most of their distributors, and will advise you to install and operate the heat pump in a way that is totally different to the way that it is efficiency is tested. The efficiency is tested on a directly connected (no header or buffer vessel), fully open (no thermostats or zoning) system that runs entirely on weather compensation. This is efficient but it needs half a brain to make sure that there is enough flow through the system at all times for the heat pump to work. The manuals / distributors tell you to fit headers/buffer vessels and zoning etc. It will always work (so no callbacks) even if the installer is thick as mince. (or if the homeowner is thick as mince and refuses to operate the heat pump properly) Unfortunately the efficiency will be godawful as a consequence.

Those universals I'd not seen before and it indeed looks like id you can live with the reduced capacity (10A vs 15A) they're indeed usable with non solaredge inverters after you get up on the roof and set them all back to non solaredge mode. Still a switching cost there. I'd still buy the tigo units that can handle more power and work with everything out of the box with no setup and at a lower price point though.

Consequences? You've got a load of electronic gar up on a roof that's unlikely to outlast the panels, and needs scaffolding and the panels removing to repair it, and only works with their inverters and their inverters only work with their batteries and their charges etc. Bend over the fence and take it up the backside on pricing and support. The minimum that an EV will draw when charging is ~ 1.4 kW. SolarEdge can't do any smart diversion here because it's controlled by the vehicle not the charger. The charger is a dumb socket that sets the available power draw. V2G will similarly depend on the vehicle rather than the PV inverter. SolarEdge don't make vehicles. They're selling you a vendor locked PV system rather today on the promise of doing something that they can't do tomorrow. Fit regular panels, regular (Tigo) optimisers if actually required for shading, and allow yourself to install A N Other inverter / battery / V2X setup in the future as and when this becomes available. Committing to installing a Solaredge inverter to go with the Solaeedge battery and the Solaredge charger to go with the Solaredge car feels like something that you should be paid to do rather than paying to do!

That's a load of money. Tesla packs are 55 kWh and ~£5.5k (£100/kWh) but add £££ for the BMS and good luck with running into a 48V lead acid inverter https://www.ebay.co.uk/itm/354146011363 (stick one in the basket and wait for the seller offer) MG ZS are 2.4 kWh at either 12.8 or 25.6 volts (model specific) and a more idiot proof chemistry (LFP) than Tesla so easy to run into a 48V lead acid inverter and ~£400 (a little under £200/kWh) https://www.ebay.co.uk/itm/275376281563 IMO automotive gear is likely to be higher quality items than no-name Lithiums. More cost effective too. For @sanch3z I'd spend the money on as large a PV array as you can now; DIY installed; and worry about batteries at a later date. Don't touch SolarEdge with a 40' barge pole unless you are completely up to speed on the consequences of being locked into their ecosystem though.

Mmsp package would also include the electricity meter, a gateway to get reads online, and a webservice to monitor both meters and calculate cop for you. £500 for that lot fitted isn't too nasty fwiw.