MikeGrahamT21

How about these: https://www.creative-cables.co.uk/metal-ceiling-roses/7053-black-cylinder-rosette-kit-bracket-screws-and-cable-retainer-8057730181235.html

According to U-wert Phenolic Set insulation (Kingspan Kooltherm) also has a very good heat storage capacity, not quite as good as wood fibre, which seems a bit odd for a foam product, but it is extremely dense compared with PIR, will get nearly a 10hr decrement delay, which isn't too bad, plus its the most insulating of materials, unless its an error on their calculator. I find buying from seconds and co is a good deal cheaper than new, the boards i received were barely marked, but they were effectively K5 EWI boards, so fibre lining on both sides, instead of foil, but that was fine for what i wanted them for. As far as a ceiling is concerned, decrement delay definitely needs to be considered, it is very important in terms of comfort in the summer, but also balancing temperature in the winter.

So a while back I decided to send an email to British Gas FIT team to ask about the re-positioning of the panels, thinking they would come back saying no, to my amazement they rung yesterday and said as long as the panels aren't changing size or power output, and the system still goes through the same single MPAN, then we can re-position, and they sent it me on an email in writing. So good news on a few parts, this means we can go with the 6 panels south, and 2 extra east, and more importantly, we have the west side roof now free for a dormer extension!!

I used these screws on everything from the roof trusses to the floorboards, fantastic quality and very cheap, and they are rated as structural screws hence the use for roofing: https://www.toolstation.com/forgefast-multi-purpose-self-drilling-wood-screw-tub/p91716

British Gypsum make a product called GypFloor Silent: https://www.british-gypsum.com/white-book-system-selector/systems-overview/floors-and-ceilings/gypfloor-silent This goes underneath your chipboard and should do the trick. I would imagine its fairly expensive though. Are you sure you need sound proofing if its just a storage space?

Absolutely, but the systems shown above, even though they are south facing, are performing twice as good as ours in some cases. The PVGIS would be about right i'd say, we did 125kwh last February with a 4kwp system. The yellow bar person got nearly 200kwh last feb, so that also fits the bill. Just seemed a bit shocking yesterday just how much difference there was. Ah well, at least we are in the right bracket for performance, i'll stop worrying about it now and move onto something else lol

So after messing around with the optitrac parameters, I can see we get a tiny bit less on a morning, though generation begins earlier, but the afternoon is much better, and longer, with middle of the day roughly the same as before, overall, we are generating more now than ever before. I've compared our solar array with others in the area (as local as were published on sunny places), and found that we trail behind massively. Looking on google maps, the yellow line is almost perfect south facing, and the red is pretty much south, slightly west, where as we are east west split, so I can agree there will be a difference, but this much?!?! We are of course in green:

I dont think it works at all in terms of ROI at present. Power cuts would be a big benefit, and then the only other thing is the warm fuzzy feeling you get from self consumption, but I guess all you are doing is paying for the electricity up front. We would still need a grid connection, and maybe only achieve a 75% overall reduction, so 25% from grid plus the standing charge, but it would somewhat protect from price rises. I'm waiting to see what contract i end up on in October, see how much its gone up, as at the moment we are on 11p/kwh which is pretty cheap really. It all depends how much prices rise, anything above 19p/kwh for us would land a profit over the 10 years.

more than likely, as i say in first three years they say its fixed at £50 a year, thereafter its a percentage (50% i think) of the profits they make out of doing it, so I suspect its very low. Trade off is unlimited warranty. Just wondered what peoples take was on this as its a little different to some of the other offerings. There is one I got recommended a while ago which is the LUX AC storage with Pylontech batteries, around £3400 for 4.8kwh all in, self install, and this also has the gridshare incentive option available, but doesn't give any extra warranty, just the standard 10 years. I wonder if people will start selling extended warranties for the batteries. Or maybe it would be very unlucky to have one break??

I agree, it is very expensive. According to the blurb, the warranty lasts as long as you are a member of grid share, so potentially forever. Obviously grid share can drain your battery too for others benefit, which could be seen as a negative.

Came across this a while ago in the Grand Designs Magazine, a UK designed battery storage system, currently they only sell 2 and 3kwh systems, with the 3kwh being about £3900 fully installed, and they're launching a 4.8kwh soon, which is the capacity i was thinking would be about right, though I dread to think how much that would be, maybe £5 or £6k? Normally, these would be a big no no in terms of return on investment for the usual 10 year warranty, however these units firstly support the grid share incentive, which gives £50 per year for 3 years, then a percentage (which would likely be next to nothing), and more importantly if you sign up to grid share, they will give you an lifetime warranty for the battery, which somewhat changes things a little? The only thing is, what they class as 'lifetime' and that i'm not sure about. What do you think, worth it or not? Or would it be better going for a much cheaper system with the same capacity, as you can get this capacity for around £3k now, with self install. I asked for a quote a while back, and they do pester quite a lot, which is a bit of a put off.

Fair enough, that sounds like a good enough reason to drop EWI. Thermal Mass, is probably better called Heat Storage Capacity, its is a materials capacity in which to store heat, and release it slowly to the environment, which in theory dampens the temperature from moving so much either up or down. A room with IWI will warm up very quickly, a really fast response, because the insulation prevents the heat from having to warm the heavy masonry behind it, but in contrast the heat will dissipate quicker than it would had the walls stored some of that heat. This room would have a low heat storage capacity. One with EWI allows the walls of the building to store the heat, with the EWI acting like a tea cosy, keeping the heat in the walls where you want it, so the room would take a long time to warm up initially, as you are warming not just the air, but also the masonry, however once warmed, it should keep a reasonably constant temperature with little heat input. This room would have a high heat storage capacity. EWI should also help on a sunny hot day in summer, as the walls will be relatively cool, so any excess heat gets absorbed by the walls, keeping the temperature down, whereas in the room with IWI you would potentially get overheating unless you put measures in place to reduce this potential. A free service such as this may help you simulate your plans, and understand thermal mass/heat storage capacity: https://www.ubakus.de/u-wert-rechner/? This also models the Phase Shift, and temperature amplitude damping which i spoke about above, which are quite important. Site is in german, so use chrome to convert it. Hope it helps.

Is there a particular reason for not wanting external wall insulation? You stand to lose an awful lot of thermal mass capacity which you may regret in the coming hotter years.

Having had a room done with dot and dab on celcon blocks, I can only recommend not doing it!! If I knew what I know now, it would be wet plastered, yes its more work for the plasterer and will cost more and leave a bit more mess, but its worth it in the long run. I now have infront of me much drilling and many cans of expanding foam to try and salvage it, as heat loss is immense, despite having enough insulation to achieve around 0.18U

British Gypsum Easifill - its a jointing compound which has been spoken off, very easy to get a smooth finish and sands well, but be prepared for a LOT of dust