Up to date solar recommendations?

Any grants available?
Preferred kit setup and size?
Export tariffs available?

I have little knowledge on the subject and we're a few weeks away from scaffold going up for the re-roof currently looking at cladco corrugated profiles and greencoat roofing systems but may be swayed by standard slate or tiles, but 100% confirmed either way.

But would like to start getting a few solar quotes together but looking at specs. to ensure I'll be comparing apples with apples in the quotes.

We have a cross gable roof with one elevation facing true south and the other roof section is half east and half west.

Let me know your thoughts on what the ideal setup is these days

IME solar installers are an utter rip off. The money and markup they are making is utterly scandalous. I had a local firm in a while back for a quote. I worked out their labour charge was effectively £2K a day per person. Probably 50% margin overall.

I've looked at the numbers several times and I just cannot justify the capital outlay. Folk say 'oh look at my low electric bill' but fail to take capital cost and depreciation into account (and don't bother throwing out the 'kitchen' analogy at me as I just don't buy it).

The only things that might sway the figures is high mileage EV and HP. I'm looking at a small EV for local use but even then, usually, I'd still be better off on Agile.

The Plugin Solar does interest me to cover my baseload during the day.

Micro inverters are mounted with the panels, which means on the roof. Typically inverters have a (much) shorter life than the panels. If the inverters are placed with the panels consider the problems of accessibility when replacing a failed inverter. Guarantees usually cover the cost of the item and doesn't usually include any associated costs e.g. scaffolding.

Posted By: Peter_in_HungaryIf the inverters are placed with the panels consider the problems of accessibility when replacing a failed inverter.

Agreed. But, I have seen a lot about larger single inverters failing when out of their limited warranty (or the firm has gone bust) so the cost of replacing one Micro Inverter is way less than a larger inverter replacement (is my rationale).
Also no DC floating about!

Choose microinverters with a good reputation and a long warranty. Replace them all when the warranty expires? Scaffold towers aren't that expensive to hire. And I might expect a microinverter installer to own one?

Does the elf an safety allow a tower on a 2 story (ground and 1st) building or are towers limited to bungalows?

"corrugated profiles"

Have got these on a couple of outbuildings and they haven't been a huge success, inevitably a screw leaks a little and lets in water that softens the purlin wood and loosens the screw and then it leaks some more.

For a house roof I would go for a system which doesn't rely on screws with rubber washers to keep the rain out.



On scaffolding - any roof worker who is prepared to cut corners by working off a ladder in these days of scaffolding everywhere, is likely to be cutting other corners on the quality of the job.

Posted By: WillInAberdeen"corrugated profiles"

Have got these on a couple of outbuildings and they haven't been a huge success, inevitably a screw leaks a little and lets in water that softens the purlin wood and loosens the screw and then it leaks some more.

That's alarming - have used 'corrugated iron' on a few domestic projects (inhabited space), no complaint so far.

Declaring an interest: we're Build4less, a building materials supplier.

On the corrugated versus slate question, it's worth deciding the roof finish and the PV mounting together while the scaffold is up, as each affects the other.

If you go with metal, a standing seam sheet lets the panels clamp straight onto the seams with no holes through the roof at all, which sidesteps the leaking screw problem WillInAberdeen describes. With through fixed corrugated or trapezoidal sheets, both the sheet fixings and the PV brackets go through the roof, so the detailing matters. Fix through the crowns rather than the troughs where the water runs, use fixings with bonded EPDM washers, and tighten only until the washer seats rather than squashing it flat. Overtightened or angled screws are the usual cause of those slow leaks that then soften the purlins.

With slate or tile, an in roof mounting system replaces the covering under the array, so you buy fewer slates. Just make sure the flashing kit is made for your chosen covering, and agree up front whether the roofer or the PV installer is responsible for the flashings and battens around the array, so nothing falls between the two trades.

Declaration: I work for a UK building materials supplier.

Thanks djh, that's a fair addition and a clearer way to put it. With standing seam both the sheet itself and the PV rails go on without a single hole through the weathering layer, because the sheets are held by concealed clips and the panel mounts clamp onto the seams. That's a big part of why it suits a roof that will carry an array.

The one thing worth checking is that the clamps are matched to the actual seam profile and sheet gauge, as there are a few different seam shapes about and a clamp made for one won't necessarily grip another properly. It's also worth asking the sheet supplier whether fitting clamps affects their warranty, and confirming the seam spacing works with the panel layout before the sheets are ordered, so the rails land where you want them.

Declaration: I work for a UK building materials supplier.

I think the question was aimed at James, but on the battery side, the best way to judge it is from your own half hourly data. If you have a smart meter, your supplier's app or account page should let you download a year of usage. Look at how much you use in the evening and overnight against what the array would make during the day. A battery only pays by moving units you would otherwise export at around 12p into the evening, when you'd be buying at 25p or more, so the yearly saving is roughly usable capacity times the number of days it cycles times that price gap. A 5kWh battery cycling most days at a 15p gap comes out somewhere around £250 a year, so compare that with the installed price and a realistic 10 to 15 year life. A cheap overnight tariff improves the sums, because you can charge from the grid in winter too.

If you meant in roof systems, GSE and Viridian Clearline are the ones you'll come across most. Check the kit suits your covering and pitch, and that the installer is MCS certified so you can get the Smart Export Guarantee. Fitting it while the scaffold is up for the new roof is the cheapest time to do it.