[Johnny Read]

Last time I checked, a 345W panel was around £130 each - you do the maths for 8 panels. I'd go with microinvertors rather than optimisers, but ymmv. I'd expect scaffolding eats a lot of that 4 grand. I got a price for a simple scaffolding to the chimney - £1200+vat.

I also had a quote from one of the those council group schemes. More out of interest to see what they would quote. I thought it was too pricey and I had no input on the choice of kit being used. Also I was a little wary on the warranty claims. They'll be buying panels by the thousands, so will get really good discounts.

Why no upload a photo just showing your roof+orientation and get some more feedback from here...

 

[Johnny Read]

From what I remember, just the scaffolding costs 1500 or so. Add additional grand for labour.

I didn't read your reply before I responded, but I agree. The real winners are the scaffolding firms. Their pricing is a real eye opener, for assembling about 150 metres of tubing and some boards. I guess there must be plenty of work, so they can price high. They are all vat reg too so that immediately adds another 20%.

It might be cheaper to hire a tower, or a cherry picker...

 

[Johnny Read]

If my understanding of your photo is correct, you'll have a fair whack of shading off that chimney. Is it shared with the neighbour? If it's not in use, why not suggest to have it taken down before you commence on PV. If you directly contract the scaffolding, then you won't be beholden to asking for a favour from the PV installer. You'll win on no shading, reduce your heat loss, and avoid future issues with water ingress around the flashing. Just a thought.

 

[Johnny Read]

he has decided to remove the chimney to save the cost of optimisers, but it did involve negotiation with the neighbour and a lot of calls to building control.

I am going through that process at the moment so know a bit about removing a defunct chimney. I'm mostly taking it down due to a leak which I think is from the top haunching, but to be honest I don't need the chimney, it's draughty, and the chimney breast takes up a lot of space in one of the bedrooms. I submitted a simple building control notice which I think cost me £130 as the total cost was under £2k. I got in a Structual Engineer to do calculations on replacement timbers on the roof. That cost me about £300. As I mentioned earlier the biggest cost will be scaffolding. But the OP may want to strongly consider a SE anyway to check the roof timbers can support the additional weight of the panels. I know if I was buying house with PV on, Id be mostly concerned about the integrity of the roof structure and waterproofing.

@Trevor Larkum - do you install in-roof pv? Someone on here posted some photos of their property, which was almost like a replacement roof from metal sheet panels, with the PV bolted through. There were no tiles under the panels. Seemed a very smart way to reduce unnecessary loading and avoid hooks etc.

 

[Johnny Read]

Does the FIT scheme have an allowance for degradation of the panels? If a system with a higher rating is capped then it will not suffer from reduced output from degradation.

Also, wouldn't a 10kW peak install limited to 4kW give higher return than a plain 4kW system? What are the maths like?