Ed Davies

It looks to me like @grahamsmythe will be changing the wiring on the DC isolator nearest the panels. Dunno about anybody else but I think I'd do that part, at least, at night. Why does the original wiring use two contacts to break each line? There's no possibility that they need the extra distance to fully break any arc, is there? An aside: I've just looked at my three multimeters for suitability for this job. The two cheapo ones with CAT classifications of some sort only go up to 300 and 600 volts. The better one which does go up to 1000 volts and which I'd probably distrust a bit less doesn't actually have a CAT classification and has lots of bare metal on the probes. Not having a dedicated tester, in practice for something like this I'd probably borrow the better protected probes off one of the CAT classified meters to test dead on the DC side for any work done while there could be any glimmer of sunlight. It's probably not that big a deal but the sort of thing which is worth thinking about. Shorting the panels by touching the wrong bits of metal with a meter probe isn't likely to be a big problem - it's only ~10  A max - but the arc you could draw unshorting them could be illuminating.

Good point. I'd think that's the common case when a company goes into administration. This Dickensian system of payments being delayed 30+ days needs to go. When goods are delivered payment should happen between the moment the pallet rests fully on the the floor and the forklift finishes reversing away. Ultimately, it's only the bankers who benefit; everybody else along the chain is paying for the borrowing one way or another.

The small print on most paperwork for these sort of things says that title doesn't transfer until the goods have been paid for in full. It's funny how the inverse doesn't seem to apply; once you've paid for the goods they don't seem to become your property. Shouldn't it be that if the administrators dispose of the specific goods you've paid for, and therefore own, to anybody else it's straightforward theft. A lot more complicated when it's only a deposit which has been paid or you've paid in full but the goods aren't yet on their premises (e.g., on order from or waiting to be ordered from their suppliers).

@DIY_Amateur, have you said what sort of insulation and airtightness levels your house has?

You can't re-use at least some of it in situ for your build? Put another 200mm of EPS on top of it, perhaps.

Because SAP was calculating on a kgCO2e/kWh higher than the actual grid was producing. AIUI, SAP has been or shortly will be updated to reflect the actual grid decarbonization so far. (We could have a long discussion about the difference between the average emissions/kWh for the whole year and the marginal emissions on a winter's evening but that'd just be tedious and repetitive.)

Aren't the SAP penalties for electricity, at least for CO₂ emissions, being reduced?

Not just overnight stops, also at work. Could be a very useful form of charging for people who don't have off-street parking.

Maybe it's that expectation that's broken. The house I'm in now is not large (haven't measured but a bit less than 80m² I guess) but it's not particularly well insulated and not airtight but still the 18 kW oil boiler cycles and short-cycles madly however cold the weather is. Last December (which included a week when I ran the heating continuously) the boiler only ran 25% of the time so the equivalent of a 4.5 kW full-time boiler. The average flow temperature to my study radiator over the whole month was 30.37 °C. Running, say, a 6 or 8 kW continuously ASHP with some modulation would give an equivalent effect. On the other hand, if the house did cool down for any reason (e.g., if you were away over Christmas (I wasn't)) then heating up again afterwards would be painfully slow. So an ASHP might be suitable for such a pile if it's more-or-less continuously occupied - kids, people working at home, retired, sick, whatever.

My vAir temperature/humidity/CO₂, etc, sensor box (sadly not available any more) has a Figaro CDM7160 CO₂ sensor in it. I think just the CO₂ sensor was about €80 in one-off quantities then but they now seem to be £39 each which isn't so bad. The advantage these have over the cheaper ones is that they don't need calibrating periodically; if my understanding and recollection are correct they have some sort of internal reference path which can be used to calibrate themselves.. The cheaper ones either are uncalibrated or do their own calibration on the assumption that the CO₂ level gets down to 400ppm every couple of days which may not be valid.

How about a trial block up just for this winter? E.g., take the plastic cover off, sheet of plastic behind and put it back. See if it's more comfortable or causes problems.

https://www.strongtie.co.uk/products/detail/joist-hanger-with-adjustable-height-strap/769 Number of nails needed is quite a lot less than the number of holes. E.g., JHA270/47 has 38 header holes and 6 joist holes but, with sufficient wrap over, needs only 12 header fasteners (8 on the face and 4 on the top) and 4 in the joist.

So long as the tops of the IBCs are below where your sealed pipes start at the house I don't see why a pump would be needed. E.g., if you have a first-flush diverter on the side of the house, where the gutter downpipes meet, the output (overflow) from that can go to the IBCs via a lower level than the top of the IBCs. The pipe will remain full of water but that doesn't matter - I'm sure I've seen rainwater harvesting systems intended for household consumption, let alone just gardening, where the pipes from the house go below ground to feed above ground storage tanks quite a few metres away from the house.

Can you explain that? If the gutters you're collecting the water from are less than an IBC height above ground level [¹] I can understand that. Otherwise, I'd think having the IBCs higher would generally make better use of gravity. [¹] Perhaps because your gutters are very low, as they are on my A-frame house, or because the IBCs are going to be uphill from the house.

Agreed, I've been puzzled by such things in the past. The only way I can see it working is if you run two systems in series so the flow from the HP goes first to the DHW tank then to another cooler heat user before returning to the HP. The cooler heat user could be a DHW pre-heat tank or UFH.

Do they say that? I can see where they say it's 38% more efficient than a condensing boiler. (BTW, it''s “kWh”, not “KWh”).

Or paint translucent ones. The ones I've seen like that were painted silver presumably to keep them cool in bright weather, again I assume, to prevent growth. Or just box them in, I suppose.

As it happens, John Ward has just this afternoon published a video explaining why fiddling with the incoming cable might be less than optimal:

So, that £40 bid: is it for one panel for £40 or the whole lot of £12'000? Seriously, that's an odd way to run an auction as almost nobody wants one panel. If I was confident it wasn't a scam and the panels were decent [¹] I'd happily pay £50 or somewhat more each for 40 panels but I don't want 1 or 300. How would I bid for that? [¹] I'm not.

Because he'll finish up looking down the wrong end of a small-claims court action?

It's a minor [¹] sadness that you can't pump heat out of the floor slab into the DHW tank. [¹] Very minor given the small amount of cooling typically needed in the UK. In warmer climates, however…

Your previous question re under floorboards/in wall pipes seems to have been ignored. I'd think radiator pipes are more usually under the floor than in the wall. That's the way it's been done in the few houses I'm familiar with, anyway. Anybody?

But you were charged for a package. The total price won't be the sum of the parts - they'll internally obviously start with their cost of the parts and add their markup and subtract a bit of a discount for the amount you're buying then think about the amount of labour to install it all and so on and come to a price. If you'd decided to take one of the earlier options with the batteries and inverter/charger it might have been, say, £4000 more expensive. But if you go back to them now and say, “oh, I've changed my mind, I'd like the batteries, etc, after all” it'll be more than £4000 to retrofit it because of the extra travel, paperwork, and general messing around. So, it really doesn't make sense to say whether or not you were charged for the inverter/charger. It's an obvious mistake in the quote and I'd expect them to apologise for it but if they say, as they seem to be, nope, sorry, our overall package price wasn't worked out on the basis of supplying one of those then I think you really have to take that at face value.

Am I understanding the situation? 1) @Home Farm got multiple quotes for different configurations, some including a battery and inverter/charger and some not. 2) The final quote, as all concerned appeared to understand, was for a system which wouldn't have batteries and so wouldn't need an inverter/charger. That quote still listed an inverter/charger but that was an obvious clerical error left over from previous quotes. Nevertheless, both parties agreed to it. 3) The system was installed and is now operating as expected, without batteries, and @Home Farm has been presented with an invoice for the originally agreed amount. 4) @Home Farm is now kicking up a fuss because he can't find the inverter/charger.

I think the solution is to simply build a brand new city somewhere specifically not commutable to London.