joth

Besides insulation, the problem with the garage is it's presumably outside the airtight boundary so you'll need to seal all ducts running out to it. How tall will the void be above the central corridor false ceiling? Could you have a descent sized hatch and put it up there? Putting it centrally will keep the duct run lengths down (more useful if you're using radial layout) but no idea about the external duct runs from there.

Afraid it's not much help now the system is not working, but the easiest way to trace central heating pipes is to get the system good and hot then use a thermal imaging camera. (I don't own one but our local council sustainability group have a couple cameras they loan out)

But it's curious that your model is no longer available, and the apparent replacement (Grohe Red and Red 2.0) clearly states it only operates at 99ºC (spec). Makes me wonder if there was patent infringement? I don't care much which we get, I truly doubt I could tell the difference of 1ºC. But I can see if I do get persuaded to go Quooker for the various other nice features I'll no doubt want to try and convince myself of 100ºC tea superiority to try and mask the £1000 sting in my pocket

This is the reason we've decided to have the boiling tap separate to the main kitchen mixer tap. The boiling tap can have a slightly smaller curve and be a bit more task focused / less splashy. That's a really good deal. Almost thinking of ordering it now just to keep in store ready for when we need it. Shame they supply the big blue filter with it - ideally I'd not have that (as we're having a whole house softener) and save on the expense of that too. I notice that's the old model and there's a Red 2.0 version too. Not entirely sure what the difference is. The Tech guide manuals on that site aren't very easy to follow (illustrations only, with no labels. Ikea at its worst). However I have just noticed it states it operates at 99ºC https://www.plumbingforless.co.uk/files/ww/merlin/GROHE Red Mono Boiling Water Taps - Technical Guide.pdf Yeah I've been told this a few times too and never actually found another with >=100ºC in the tech spec. I was under the impression it's something to do with WRAS rules not allowing 100ºC boiler to be connected to the mains supply for risk of malfunction sending boiling water back out the inlet, and Quooker having some patent to get around that. /shrug Another safety feature of the Quooker is the boiling water is aerated, making scolding much harder. The rep at GDL was happily passing his hand right under it without problem.

It depends entirely on the size of the battery, the rate you want to charge/discharge it at, and any additional features you might need (like load transfer switching / offgrid backup mode / multiple input/output voltage or phase support / remote monitoring etc etc) Your question as it stands is comparable to "how much does a car engine go for? I don't know what car it will go in".

The bar of proof on them is very low as it was a "package quote". All they have to do is send an invoice for something like: Components actually provided = £X Labour & administration = £Y Profit = £Z And ensure that the sum of X+Y+Z matches what they billed you for. While it would be polite for them to make the value of X be reasonable, they've got a fair degree of liberty to freely choose the values they want for Y and Z. After all you have no contract that states they can't cover their backend costs, or places any cap on the profit they may make. You can go back and forward digging heels in and insisting they provide this itemized invoice, but I can't see how, if forced to, they could ever fail to invent one that you have no recourse against, unless the profit really does come out so obscene and you can make an argument you are a vulnerable individual and victim to pressure or fraudulent selling. Otherwise I think you need to put less emphasis on having them prove they haven't charged you for things you didn't want, and instead argue you were genuinely expecting to receive an additional, redundant charger/inverter. But the fact it's taken you so long to notice the lack of it somewhat diminishes that.

Further, if you used the money saved on the inverter to instead buy a extra or higher rated panels then the low-light output will increase simply by dint of having more panels, at a cost of limited peak output. Averaged over their lifetime this might well give greater annual yield for a given capital investment, especially in places like UK that are not renowned for 365 long cloudless days of sun. If the constraint is not capital cost but space to install them, this logic probably doesn't apply. Likewise as inverters get cheaper and generally more efficient, it doesn't seem so useful to consider.

The quote I'm currently working on isn't much more detailed, but at least does have the total power capacity and installed dimensions of the array listed on it. The inverter and optimisers are not specified though, I only know exact details about the inverter as I specifically asked about the model on an email chain (debating 3 phase vs dual inverters). I assumed I'd get an itemized invoice before having to pay, but this has highlighted I really must do so. It is curious what the charger was ever intended for. Did you ask them for battery storage?

Good news is UK gov (or the civil service that runs it) is aware of the increasing divergence of building regs ventilation requirements vs low energy best practices. See recommendation 10 (table 1) on pg 18 here. Timeline to address "2019" yeah.... Does someone have a guide to making this home made blower? Sounds a fun project. I'm assuming it's really just for diagnosing leaks not making an accurate measurement?

I seem to remember, from years ago, it is/was. 100°F ~Body temperature. I guess, it's an obvious number to go for... LOL hadn't thought of this -- another justification for the double-TMV shower in our ensuite ?

Depends entirely on the model and capacity of the charger/inverter in question. Fwiw victron is great gear, had one of their charge controllers on my old caravan in California, but generally seems overkill for a home installation. It's really in its element with marine applications where regularly switching between ropey shore power of varying voltage and frequency, a spluttering engine alternator, a dodgy old lead acid battery bank and an under specified solar array.

If you have SolarEdge inverter, when you power it up it should go through some procedure where it turns the optimizers on one-by-one and reports back their status, look for P_OK x/y on the display I think this is saying x out of y optimizers are activated. See page 40 of https://www.solaredge.com/sites/default/files/se-inverter-installation-guide.pdf If you have a non-SolarEdge inverter, I think you need to have a SolarEdge Safety & Montoring interface (between the inverter and the panels) to activate their optimizers https://www.solaredge.com/sites/default/files/se_installation_guide_safety_monitoring.pdf If you have their online monitoring platform, I think you must have optimizers installed for it to work https://www.solaredge.com/uk/products/pv-monitoring#/ The final way to know is to shut down the system and then put a DC voltmeter across the DC connections into the inverter (outputs of the panel strings) -- if they have optimizers the voltage read should be exactly 1V per panel in the string, however if you don't have optimizers this could be a dangerous experiment to perform (esp on a very sunny day) so I wouldn't recommend it.

Perhaps partially answering my own question, for Passivhaus certified components the PHI database provides numbers that seem more comparable (presumably measured through a common protocol) https://database.passivehouse.com/en/components/list/ventilation_small This puts just 4 dB between those units I listed although it looks like the Brink Flair 325 if the newer/better comparison, 1.5 dB quieter than the Zehnder

Regardless of perceived noise levels, measuring noise and comparing figures across manufacturers looks like another can of worms (reminds me of comparing bike lights -- every manufacturer claims brighter AND longer battery life than everyone else). e.g. taking some well regarded, comparable models: Zehnder Q350 https://www.zehnder.co.uk/download/19868/118402/en_uk-42893_0.pdf Brink 300 https://irp-cdn.multiscreensite.com/404d9e8c/files/uploaded/Renovent Excellent 300(Plus) Technical Sheet BrinkHRV.pdf Zehnder claims 16 dbA vs 30 dbA for the Brink, on their respective lowest speeds (150 m3/h vs 90). So to the novice that means on lowest setting, the Brink is 2^((30-16)/3), or 25 times louder? This is most likely because Zehnder measure at 3m distance but Brink don't state what distance. I have to admit, like with ASHP, I've thus far not really analysed any of this in detail and just relied on picking a major brand manufacturer that states they have the the quietest model so probably comparably good to next one.

Welcome! That's a great set of improvements! We're in a similar project right now, but starting out with the MVHR goal and everything else has followed from that... (EWI, floor insulation, air tightness improvements, etc). Some comments / questions that come to mind - not specific suggestions just list of things to think about and spur more ideas here really. - Does the utility room have any wet appliances / laundry duties? If so extract maybe more appropriate there - But if so, 2 supply feeds vs 5 extract sounds a very unbalanced system (even 3 supply vs 4 extract seems unusual, esp as the kitchen is generally "double" hence it's 3 vs 5). The air flow rate (and hence noise) might be extremely loud in those fresh air supply room. Normally the supply values outnumber extract valves (I have no idea if that's a "best practice", but it makes sense to me as the extract rooms tend to be places where a greater noise level could be more easily tolerated) - how many bedrooms / reception rooms do you have in total? It would seem a mistake to not plan to supply fresh air into all of them (even if the install is phased) - how long is it since the insulation was put in? I'm thinking you need a full year or two to determine if it's created any new damp issues (esp with respect to any rooms that you're not planning to put fresh air supply into, if any) - do already you have numbers for the existing level of airtightness (in air changes / hr), and the total floor area of the house? Getting a blower door test done might be worthwhile.

The other thing to bear in mind if sharing units is you need to be able to route the drains of the showers into the same vertical stack. unfortunately our two upstairs showers are in opposite corners of the house so no way to get them sharing a heat recovery unit. The downstairs shower is directly beneath the upstairs one, but again can't share a vertical WWHR as there's minimal vertical drop from the downstairs shower into the horizontal drain below the slab. We could have them share a horizontal WWHR unit beneath the downstairs drain but they're less efficient anyway and not really designed for sharing. So on balance, it's probably only the ensuite that will get one installed. Likewise routing the cylinder inlet via the ensuite WWHR is going to be a bit of a PITA but I think it can be done (in reality, just one more large and lagged pipe run coming back from shower to plant room). I have a slight concern in the pressure drop this will introduce (in addition to a water softener) but I guess worse case, it's easier to retrospectively bypass it than add it in! This is reassuring to know. After writing the thing above I took a shower myself and was contemplating the margins must be enough to have it work reliably. I had been imagining 45 vs 48ºC which seemed tight, but in reality it's more like 40 vs 50ºC which should be plenty of operating margin.

It can still be useful but you'd need to use the WWHR to preheat the cold supply going into the cylinder instead of (or as well as) the cold feed to the shower. I'll also go on a limb and suggest even without this, your DHW doesn't need to be that much above showering temperature for it to work well so long as the shower thermostatic mixing valve is working properly (necessary for any WWHR install). While the TMV will start off only drawing a small amount from the cold feed, as that cold water warms up it will have to mix in a higher and higher proportion of cold to achieve desired temperature, thus reducing the DHW water usage as intended. Overall the system would be working right at the boundary though, so just a small decrease in DHW/cylinder temperature and it suddenly wouldn't work at all as you say.

Last time we were burgled we were sleeping upstairs at the time. I could have been on the 999 call a good 5 hours sooner had the alarm still been working

Oh, currently the league table has Octopus offering 5.5p on their fixed tariff, so actually beat your current FIT export rate - I didn't quote it exactly as it's liable to change between when anyone looks at it and when you go to claim it :-) and not realizing that 0.5p would make all the difference. Also Octopus offer some sort of time-of-day variable rate, I assume that only makes sense if you have battery storage and can cleverly time when you export (on the assumption that on sunny days the rate will plummet exactly when everyone else is generating), but I haven't actually researched that at all.... again very liable to change between now and when I eventually get connected to it

per @Ferdinand up thread -- about 5p/kWh There's a league table of 1 here: https://www.solar-trade.org.uk/resource-centre/advice-tips-for-households/smart-export-guarantee/ (more will appear in Jan when the SEG legislation comes into effect)

I can't tell from their material if they have option of a fail over to mains if the rainwater supply runs out? There's no WRAS markings so I assume not, I assume if you have that then being mains connected is basically illegal, but would be interesting to confirm?

Stands to reason then, Reykjavik is about as far from the Antarctic as you can get and still have running tap water. Poor old Spain on the other hand ... ?

So at what point did you start talking to the electrician about this? It seems fairly late in the scheme that you normally get an electrician really involved but I'd like to have had the lighting design done much earlier, to ensure our assumed room layouts will work well with it and so on. (Complication is I want to use the main contractor's preferred sparky, but until main contractor is signed up there's no much way of having that conversation)

All you really need from the EPC for the RHI calculator is the expected annual heating and DHW load for the property, you must have some reasonable idea of these already to have designed the heating and decided on a 14kW ashp? It's fairly easy to work through the RHI calculator with a few scenarios to at least get a range. You can do a worst case scenario of 15kWh per m2 of floor area (i.e passive house) and see what the RHI would be on that, in reality an independent EPC would never estimate it that low so that will give a minimum level of compensation. FWIW my quote is £9k for ashp install including high spec 300L UVC with 100mm of insulation and quite a bit of plumbing, and it says between £7k and £3.5k in RHI depending where exactly the final EPC falls. As it's a retrofit I'm also pushed towards MSC anyway to get the low rating on VAT, and besides if I'm paying for an install I'd rather not be someone's first attempt (the market for reputable, experienced installers in our area is thin enough without adding a non-MSC constraint)