PeterW

Big ones yes, micro ones no. I saw inside an AP Micro and most of the back of it was anodised black aluminum as a huge heatsink as they are designed to sit behind the panel on the roof. Last time I checked they had one on test for something like 4 years 24x7 at 200% load and it was still going strong. As @JSHarris will attest to, this is more about decent components such as capacitors and removing any superfluous moving parts as that is what breaks first ....

You don’t need a lot but beware that you could bleach the oak slightly so may have to do the whole truss ..!

Thornes sell small amounts. I’ve bought from them before. https://www.thorne.co.uk/index.php?route=product/product&product_id=7434&gclid=CjwKCAiAhp_jBRAxEiwAXbniXc3zm9-UWhJQDzVfbd61UnUI_AyyV6EydWI_IQ2Rq4fEWKnVhRAGKBoCOV0QAvD_BwE

Unless he was subsoiling its unlikely a plough has hit it as most farmers have gone min-till these days and even when ploughing you're only in 8-12" at most.

That is extruded polystyrene so 25mm is just to stop an element of heat loss. Shredded paper or blown cellulose would need 100mm or more.

@JSHarris @Nickfromwales Didn’t SunAmp look at using Aerogel in their units instead of the VIPs on the side panels ..??

Idea for wrapping steels etc so you get the thinnest insulation possible and don’t make steels huge.

Only if you have pockets that are very deep and very large ..!! Aerogel is eyewatering in price and only really used for insulation of complex or high end systems - think NASA..! It is available as a standard insulation but from memory it’s £100/m2 or more.

There is the nub of the issue. Impact drivers were designed to drive anything you throw at them. Concrete screws, frame fixings, you name it. They had the torque and more importantly the clutch systems that mean you don’t fry your nice 18v drill driver which is designed to do something different. Its a choice of cost vs value - I don’t use mine 8 hours a day but want one tool to pick up when a screw needs to be placed - I don’t want to decide whether it’s Impact A or Impact B... it’s the impact driver ! Over 15 years I’ve slimmed down the tool collection and usually it’s now just the Makita drill driver and impact, and the Fein multimaster that make it into the car. Having specific tools for each job just doesn’t work when they are £120-150 each.

Impact driver as in cordless for putting screws in ..?? You don’t use them 8 hours a day continuously so buy what the trade use - Makita LXT or Dewalt. Just pick your battery ...

Chat to Wagner The APsystem micro inverters are good, as are the JA Solar panels. They do the IFRS in roof system so could probably sort the whole lot as a package, with the 3 pairs feeding the 3 flats.

For the cost - and if you have the space - I would put 6 panels on in 3x2. You can get a dual micro inverter that takes up to 600w, and that would give some baseline load for probably £2.5k all in. Offsetting the cost of the clays too will be significant.

I’ll go against the grain and say it’s a bad idea ... Stainless here would need to be quite thick, and you would need a serious mesh to get good adhesion (purely mechanical) to the the steel. Materials would be more than a former, and given you want to also tile it there is no real benefit over mild with 2 coats of red oxide. You could manufacture the same in fibreglass for £80-100 at most and do it in situ.

Is that per unit ..?? That’s only 3 panels in honest, would be nice if you went the GSE in roof route too as they actually work out nearly as cheap as tiles and look a lot nicer. TBH I would use micro inverters on all of them - one per panel - and then run to each unit and forget about it. Quick, simple and only one isolator in each build.

What is the final build up of the walls then..?? And 75 panels ..??!! Is that a typo..?? Start with someone like Wagner Renwables or ask @Nickfromwales for his contact.