Alan Ambrose

Well I've been researching this some more and thought I would post an update: + The headline is that this looks a significant can of worms for a lot of self-builders unless you have very mass market design sensibilities. Barratt home anyone? + This video by Pilkington says (about 1/2 way through) (roughly) 'yeah, if you want Grand Designs, then the Simple Method won't work for you'. https://www.youtube.com/watch?v=NrY7odmPm68 + I did a rough-and-ready 'Simple' analysis of our current design. If my calcs are correct, then we're way over the limits atm. + There's a lot of the 'Simple' procedure which doesn't make a lot of sense to me e.g. why would you want to limit North facing glazing? + @Susie - as you have pointed out, there's no allowance in the 'Simple' method for any mitigation like the various forms of shading etc. So the proven Mediterranean methods: outside shutters / awnings / vegetation etc etc etc are totally ignored as are modern methods e.g. Pilkington's low-transmittance SunCool glass. + That suggests TM59 modelling may often be necessary, which might be properly expensive if you get someone else to do it. + There's a comparison of a couple of modelling packages here: https://journals.sagepub.com/doi/pdf/10.1177/0143624418792340 + And I note that one of the two pieces of software mentioned there: EnergyPlus, is free https://energyplus.net/ All-in-all quite a complex headache IMO. Designed to protect city flat dwellers who largely have to live with what they've got (and cope with the window opening implications re noise / pollution / security / safety), I question the relevance for self builders who usually have control of their own building and can therefore retrofit (e.g. shutters / awnings etc) later if they find they have a problem. Also, bulk house builders will only have to model a 'sample of homes' (and Part O doesn't give hard criteria for the sample) and therefore they can spread the costs over an entire development, whereas the self-builder will usually need to do a one-off i.e. 100% analysis. Hmm, another little industry and new build tax has been created.

Well I think 'O' is badly thought out. 'No benefit from trees or curtains' is dumb'. Our present place was v. hot at times before we planted the garden up and put in some thick curtains. (We didn't design it and its a barn conversion, so lots of the design decisions were made in the 1850s.) It's fine now and the plants we've used love the sunshine. I think my strategy will be to apply for planning with ample glazing and then reduce glazing / add solar mitigation with non-material amendments as necessary. There's no point in doing all the calcs if planning hates the design for other reasons. And planning won't be that bothered if we want to reduce the glazing later.

Well I just read through part O - my first reaction was hilarity . The expectation is that you do this after you've adjusted your windows following your heat loss calcs and before your planning application? "Despite its name, the Simplified Method is not entirely simple". Yeah, well.

I believe so if you change the GIA. Maybe if you have a 'bit that you could chop off' or other simple amendment rather than a complete re-design you might get away with a minor amendment. In theory your planners should be able to tell you based on an simple description of your proposed changes. Depends on how helpful yours is. A number of LPAs have a description on their web sites of what they think is minor/non-material.

>>> What is the benefit of a mortgage advisor specialist vs self serve. I think it boils down to how standard your situation is. If it's run-of-the-mill then self serve is fine. If it's a bit special, then broker. There's nothing to stop you doing both in parallel and taking the best deal.

If it's any consolation I have a bunch of pipe and plasson fittings which looks as messy. It would look better if plasson just made the caps in black or 'pipe blue'.

>>> Not worth a knitted flue cosy. I think that something striped and crocheted would be lovely.

>>> The law of conservation of energy A very clear explanation, thanks. And I thought that 'conservation of energy' was something to do with lying on the sofa and being too lazy to get the remote. I should have paid more attention in school.

>>> I thought it was around 15p/kWh? Yeah, I think you're right. BTW the Octopus Agile pricing suggests a 120% markup.

Oh dear, I seem to have started something...

>>> average wholesale price they pay is around 5p/kWh OK, well I guess it's about time I started my electricity markets education... https://www.ofgem.gov.uk/energy-data-and-research/data-portal/wholesale-market-indicators These do seem to suggest 3-5p per kWh. So, why are we being charged anywhere between 15-43p? The fuel markets seem to have only a 50% markup? https://www.racfoundation.org/data/wholesale-fuel-prices-v-pump-prices-data

If you can split your panels into groups that are shaded at the same time and this arrangement suits your inverter (number of input connections, min/max DC voltage in etc) then you should be home and dry.

>>> Just been onto Eon Next and they now say they need a photo on the electic connection in place before they will book a installation, which will be in 6-8 week wait! That's for meter installation on a new line, or just a meter swap? For a straight meter swap, I've contacted Eon.Next by phone and by email (different groups I think) and both told me 'someone would call to make an appointment'. That was a few weeks ago now. I got another couple of invites from Eon.Next for a smart meter install yesterday. I fall for it every time. Answer their questions ... then it thinks for a few seconds and says 'no meter installs in your area'. Well why did you xxxx send me an invitation then...

>>> I'm curious why you consider grid export a "luxury"? Well tongue-in-cheek i.e. giving someone else power at a small fraction of the price they would sell me the same thing. I don't have much of an understanding of the electricity markets, but the general feeling here, I think, is that the DNOs are taking the ... mickey.

Never one to miss an opportunity for analysis:

>>> So with a bit of forward planning, if you heat water and charge batteries around the high production times, your house will be less hot. Whoo that's v. clever.

You guys are fantastic >>> Are you talking of a totally off grid system? Probably with batteries? I was actually thinking of something like that i.e. without the 'luxury' of dumping excess power back to the grid. Seems then that the panels will just heat up more when the 'full load' is not extracted? Thanks also for the answer to the PVGIS question - I was quite liking the 20 degrees roof slope anyway as it gives max internal space with a nominal 1.5 storey / 7m ridge height - so that adds another plus.

(1) PVGIS seems to give me 67% power output for North (vs. South) for Suffolk. Is that really right? Azimuth kWh p.a. / kWp % vs. S Westerly 125 780 74% Easterly -55 986 93% Dead North 703 67% Dead South 1,057 100% This is for 20% roof slope. (2) What happens if you don't draw the max available power from your panels at any time? And you don't actively divert it to heat hot water or send it back to the grid? Does it end up as heat at the inverter or maybe in the panels themselves? Or something else?

Well there's a couple of other suppliers mentioned in the thread so far, and I, for one, would be interested to know who these great suppliers are. I need 3 replacement sashes atm.

For anyone based in East-Suffolk and/or thinking they might build there someday, the LPA are soliciting feedback on their 'Supplementary Planning Document?' re custom and self-build housing policies. So, this is your chance to have your input to 'the rules'. See: https://eastsuffolk.inconsult.uk/CSBSPDINT/ The consultation runs from 1st Feb to 15th Mar.

>>> plug-in Tuya style SSR with low-latency, zero-crossing switching It would be helpful if it switches cycle-by-cycle so you could have all the way from 0 to 100% of a 3kW immersion in, say, 2% steps. Two drives would also be useful for those of us that have 2 immersions in one tank. I think the electrics part (earthing / switching / fallback / wiring / temperature measurement etc) is more tricky than the electronics part - but then I'm an electronics/software guy. Current transformer sits in the meter box? Another on the PV inverter? Need to convert the CT signals to digital to send over wire/wifi?

>>> Air pressure making the glass flex and breaking down the seal? I think probably that one but I will take photos as you suggest the next time I have one out. There doesn't seem to be much rhyme or reason though - I can see one which was replaced over the last few years has already failed, whereas some older ones still seem to be good. The larger units seem to have tempered on at least one side. I did order some from Pilkington directly way back. Unfortunately my record-keeping isn't good enough to see which units were replaced by which supplier.

Well half-pints all round.... We completed on the plot yesterday. That only took a year and about 100 hours of my time.

Yeah, I think the press was (guess what) a little sensational here. I suspect that given both parties have been a greatly disproportional here with costs, that the judge will order recovery at say, 60% (and the amounts probably not made public). So, say: + Mr Downing ('winner') - pays 40% of his own costs of £95K i.e. £38K. Plus he receives £32K damages to pay for fixing the knotweed. + Mr Henderson ('loser') - pays £32K damages + his own costs of £100K + balance of Mr Downing's costs £57K i.e. £189K. So it would have been far cheaper for either of them to pay for the £16K knotweed fix directly themselves or, even better, to split the cost. The great beneficiaries are, surprise, the lawyers - who do get to pocket £195K between them for arguing over a £16K problem. That is, unless the judge decides they were breaking CPR 44.4 (1), and gives them a little penalty.

@markc re: That’s a hidden gutter and the down pipes will be internal, common arrangement on industrial buildings. I'm interested why on industrial buildings - presumably some practical advantage? The engineer in me says 'no', but I do like the look - and the picture I posted above suggested they kindof built the building as normal 'and then put the cladding on the outside'. And as the cladding is largely just looking good and keeping most of the rainwater off the vapour barrier, then I guess it will work. I get the point re not getting the gutters blocked, but where I am now, they have never blocked anyway as we don't have any overhanging trees. I guess we're used to soil pipes boxed in on the inside and we're not paranoid about them leaking - we just take care to do the work well.