joth

@SteamyTea not directly answering the question but one local installer did emphasize a "hidden" benefit of the solaredge optimisers, for him, is they collect and report per-panel long term statistics. So he can go back after 5, 10 years and see how it's still doing and diagnose if there has been any unexpected drop off in performance. Also, if one panel fails the optimize keeps the string still working until in can be replaced. (obviously if the optimize fails you're snookered). I think it can even automatically send an email to owner/maintainer in case of failure too. So anyway this is my plan to handle any future diagnosis needs. ( Oh and also aside from the primary benefits of dealing with shading, the optimisers also mean we can have a smaller and more efficient and claimed quieter and longer life inverter too)

The captive fly lead on the back of each panel already has a connector crimped onto it (on every panel I've seen). So you'll need to connect each of those to an extension to your junction box. So net result is you'll have double the number of connections (and connectors) with your plan vs just daisy chaining them in the normal way. That's before counting the additional connections inside the junction box.

Yes, by no means will all Passivhaus builds automatically be plus rated, but I can see if someone is setting out for plus rating it will be easier to get it on a new build vs a retrofit, hence my assumption there are very few retrofit pluses out there. That said we definitely didn't set out with it as a goal either. Just our roof lends itself to a full pitch of PV and it actually made the planning application simpler in some ways. I actually found several "bugs" in out PHPP since the chart above was made, which puts us more comfortably inside the Plus loci (lower demand; further left). I'll dig out the details tomorrow, but heating system temperature and the heuristic for circulation pump wattage (!) was a large part of it.

@Dan Feist great stuff! Where abouts are you in the country? Our construction starts January 7 so no actual figures just yet. Soon! So very soon. (move out in 3 days time.... So soon) Existing is block and brink, new parts will be timber. It's an interesting house being a 60s cross wall construction, we actually demolishing the two external non-load bearing walls to rebuild in place to a higher spec. Not sure anyone has attempted this before (for passive house reasons) Yes, will be certifying. To confirm, there's 4-5 enerphit Plus now (i.e. retrofits)?. I thought there's only one (the Manchester pair of semis) but maybe out of date. I can imagine, like everything else, achieving it on a new build would be much simpler as you can design everything around the microgeneration. We have to deal with the aspect and roof pitch we inherited.

normally you just hook the +ve MC4 connector from one panel directly to the -ve MC4 on the next panel, no junction box needed. Even if doing it inside the building I'd do the same to avoid lots of extra cable length looping back to a single point? Is it an additional risk of electric shock if doing all the connections indoors? Also, fwiw, my contractor had some grumble about bad experience bringing each panel connection inside (in that instance for micro inverters) causing a lot of extra faff from risks of air leakage through all the penetrations of the airtight envelope. We decided to put the DC cable, inverter and connection to AC (meter) all outside the airtight boundary for that reason.

I was all sold on cat7 after reading loxone's praise of it: https://www.loxone.com/enen/cat7-cable/ But that's 6 years old. Things have moved along since then, cat7 perhaps not caught on, loxone came out with their own 3pair "Tree" cable, GG45 connectors seem a pain to deal with etc etc. I think cat6a is as far as I can bring myself for light switches, and *perhaps* splurge on cat8 for the media drops. (Terminate in screened RJ45 but gives the option to upgrade the termination in future if needed)

Well, Architects are quite happy working in unitless and qualitative measures; see also visual weight of a design, degree of overbearing or overlooking on neighbours, harmony, speaking the local vernacular, feelings of space and light, etc. To be honest the vast majority of the population are also quite tolerant unitless and ill defined measures. It's just in the more obscure corners of the internet you find the folks (some would even say, pedants) that get het up about it

One thing this brings to mind is several of the architects we spoke to locally prefer to make planning applications with black and white / line drawings only, rather than colour "impressions" of the property. Ours went through this route no problem, we're in conservation area (but not AONB). The rationale is that if you put colours on the application then they're more likely to add conditions holding you to them, or get upset if you don't exactly keep to it, but with black and white and only a terse description of materials used it leaves a lot more flexibility in choice. More generally it was implied that unless they really go to town with detailing and photo realistic perspective ray-traced renderings, there's a risk that "cartoon like" block-filled colour illustrations can actually remove a lot of the 'wow factor' that the viewer's mind might have otherwise been willing to fill in for itself when looking at basic B&W elevations & plans, if you see what I mean? I wonder if that's in part what is happening here.

Might be true for commercial users, but for domestic 3phase there's no requirement to balance phases and you're billed based on the instantaneous use (or export) netted across the phases, so there's no penalty for splitting generation or consumption across phases. This is codified in Part C of the SMETS V2 spec. Snag: no one makes a polyphase SMETS meter, but the existing non-smart alternatives are supposed to bill the same way. Anyway I agree you're unlikely to need 3phasr but stillI I'd get a quote it anyway and if the price difference is negligible do 3 phase. you can always have your supplier fit a single phase meter initially, but will give future flexibility that's very expensive to retrofit.

Cat 7a exists - and isn't *dramatically* more expensive than 6. Would go for this one myself Why stop there, Cat8 is available and also not dramatically more expensive https://uk.rs-online.com/web/p/cat8-cable/1757241/ https://www.datacenterdynamics.com/opinions/category-7-and-7a-see-their-sunset/

It sounds rather like you are reinventing KNX, which is already the established international standard for exactly this sort of "one wall box in each room" KNX has many drawbacks so I'm not entirely surprised it's never taken off (that said New Zealand and Australia have now integrated it as an option into their electrical code so maybe it's going to have another burst of life, well, before the Connected Home over IP project cannibalises it, even if they're currently wireless only) Problem with anything home brew for this is some functions like light switches are mission critical to safely using a home, so I pity the poor person next trying to repair the custom designed system when it eventually fails. This is the deciding factor pushing me (somewhat hesitantly) to loxone: say I'm in hospital and the lights stop working, there is (today at least..) a local company that my family can call to come and fix it. For the best future proofing against all eventualities, last time we did this conversation @ProDave made the great suggestion to put 1mm2 T&E and a cat6 drop into each switch, which is what I'm now planning. A future owner can then easily roll back to old school switches, or the latest whatever. (I was actually going to use KNX cable as I had got a reel of it and Loxone would work over that fine, and perhaps benefit from the slightly larger wire gauge, and gives a clear KNX upgrade path if I want it, but CHIP gives me the hunch CAT6 is the way to go now. )

It's not entirely conclusive (and not actually sure it's the thread I remembered), but...

To solve the 3kW limit, you can be a contactor on each circuit - basically a big old mains operated relay. You'd use the sonoff or whatever to control that. I'm going to do this on a few specific circuits (110V transformer for my US appliances, garage bench sockets, perhaps the outdoor sockets) but in general I really agree with your other point that the "room" is the wrong unit of control for sockets. (Unlike lighting circuits) Another option recommended by a friend from the BBC is do what they do in control rooms and have 2 circuits to every socket. "12hour" and "24 hour". The 12h circuit gets shutoff out of office hours. But then why not run a 3rd circuit for battery-backed 24h too? And before you know if the house looks like https://metro.co.uk/2019/11/03/house-worth-1350000-enough-plug-sockets-everyone-street-11033568/

We were recommended to have one back when we were planning forced air (fan coil) heating upstairs. It also resulted in a very slight PHPP improvement, so I didn't think much more about it. If it needs more frequent replacement, and costs more, and we're not thinking we'll need forced air heating now (rely on downstairs UFH only) maybe I should look again and remove it from the spec.

Even a barely large enough one that is always running at maximum capacity? That will surely be noisier than a correctly sized one. That was my point Exactly what I concluded too, thanks ?

I seem to understand ASHP follow Goldilocks sizing rules. Too small they will work too hard and make loud noise, but too large it will not be able to put out low enough power so end up short-cycling on & off which reduces efficiency and is also the most annoying noisy (stop/start clicking). Get the size right and it will just make constant low hum. Fortunately modern inverter driven designs have a wide operating window so being a bit too oversized is less of a risk these days (all AIUI)

Lovely. Easy to clean, or any risk of staining? Does limescale marks show on a black sink? (Kitchen is where we'll have the only non-softened tap, of course) Is it this one? - Blanco Subline in Silgranit

Sounds like your EPC is figured at current building regs quality of build, around 100kWh/m2 per year. If you've been in for a year you can presumably get a more accurate estimate of annual heating demand from your gas bills. Also have you had a room by room peak heat load calculation done, and know what the peak heat load is for the house? Has the house has an airtightness test and how is ventilation managed? It sounds like peak heat load could be on the high side and converting to ASHP on its own to reduce bills risks tackling the symptoms not the cause of high heating requirement. I wonder if it maybe worth investigating fabric-first options to reduce heat load prior to making changes to the heating system design.

I'm struggling to remember. I think we actually figured it out for ourselves as we were looking to replace or extend over it and researched the permitted development rules on it. We never got around to changing it at all; sold on that house last year and again no question was raised about the heating system in the conservatory. The buyer didn't seem to have a survey done at all (she was downsizing and in a massive rush to complete before the first Brexit deadline), the buyer's solicitor did ask about the age of the conservatory we said it predated us, at least 20 years, which I think was enough for them to figure it's compliance to BRs was very low risk. By coincidence my wife now works for the conveyancer that handled that sale for us and thinks they'd pick this sort of thing up when representing the buyer, if the conservatory/alteration is "recent". They'd ask for the seller to confirm it was done under permitted development, request any certificate for the same, and/or arrange indemnity insurance if any issues come up.

That independent heating system requirement must have been around a while as we were warned our house was in violation of it when we bought in 2005.

I was thinking of doing something similar, but boxing it in over the stairs to form a "cupboard" accessed through a door from a spare bedroom to the side. In the end we're going for loft installation (now we decided on warm loft, it's just easier) but I did like the idea of easy filer access through a cupboard door in the box room.

Welcome!! What are you going to do with all that gorgeous parquet? is the question everyone will be asking you from now until you put your UFH in. At least, it is for us. (Relatedly - anyone in need of 50m2 of gorgeous parquet? available in 3 weeks time.)

To clarify, it's a very expensive addition that you don't think is worth the cost, or the cost isn't the issue so much as it was aesthetically inappropriate for the rest of the design? The do look contemporary and very attractive to me; currently I've been planning very basic skirtings but maybe I should have put a bit more thought into it.

Indeed yes, sad as it is, they were surprisingly prescient in NOT making any prediction that homes would have high levels of insulation & airtightness in 2020. The aerogel thing made me laugh. Just like the so much contemporary thinking on climate change, it was all "futuristic high tech materials will save us!", when in fact most of us use recycled newspaper and expanded polystyrene. The materials have existed for decades, what makes the crucial difference is actually bloodywell using them.

To be fair, pads-not-plugs thing was the only prediction from Howard that he actually got wrong. While I totally agree his forecast of futuristic zoned smart heating should have been completely redundant by now, sadly it stands as a very accurate prediction of what what, today, is generally considered state of the art home heating design in the UK.