Quotes and install questions

Zarch

Hi all,

Three potential locations on the property in Sheffield.

• Main Roof (maybe 9 panels, 2.7kWp) SW Facing - PVGIS approx 2500kWh
• Dormer Flat Roof (4 panels, 1.2kWp) - SW Facing (flat) - PVGIS approx 940kWh
• Rear Extension (3 panels, 900kWp) - E Facing - PVGIS approx 770kWh (gets sun from sunrise, but has shade issues from noon onwards)

Wife isn't happy about using the dormer as the builders (4 years ago) said the vinyl roof will eventually need replacing.

After weeks of reading forums etc i'm pretty happy with all the FIT and savings figures i've pulled together. I think I understand them all.

I've been monitoring my own usage for the last month via an old Current Cost usage meter into a Raspberry PI running measure it and then uploading to PVOutput.

** I can post my PVOutput url, not enough posts **

Electricity bills also confirm approx 3700kWh per year usage.

Quotes so far
1. Ikea via Solarcentury - 13 panels £5,600
2. 'South' installer - 11 x 300w = 3.3kWp (£5,200), 11 x 320w = 3.5kWp (£5300) Solaredge inverter
3. 'North' installer (Bisol panels)
Main roof and Rear Extension (12 panels x 300w = 3.6kWp) - £5470 (plus power optimisers for shade)
Main roof and Dormer (13 panels x 300w = 3.9kWp) - £5300
All three locations (16 x 300w = 4.8kWp) - £6350 - quote says permission required

4. 'Local' installer - hopefully coming next week.

1. Don't think I will be going any further with Ikea from comments i've read.
2. This quote is via emails, photos and google maps. No site survey yet, so discussions are on-going.
3. Again, this from photos and emails etc. They've also gone to the trouble of checking the building plans for the dormer for the flat roof weight bearing.

Would I be right in thinking both these quotes on the high side? I've seen £4k upwards on here for up to 4kWp systems.

Both quotes have come back with around 10-11 year break even calculations.
Which sort of ties in with the spreadsheets i've pulled together using PVGIS/FIT/energy saving etc.

I think whether the system costs £4k or £5k/£6k, it just seems to add a few years to breaking even. Obviously, the cheaper the better.

Are these private installers open to negotiation? Are these first quotes ripe for discussion?

Any thoughts on any of the above?

Cheers.

Martyn1981

Hiya, my first thought was that your quotes aren't too bad as a starting point, since often we see £8k+ or so in first posts, so that's a good start. A bit closer to £5k for 4kWp or £6k for 5kWp would be even better.

If you are considering the E roof, and that makes sense to spread generation across the day, then the shading leads towards SolarEdge, and SolarEdge leads towards using the dormer roof too, as you'll no longer be limited by panel orientations, pitches etc, but can slap down any ole mix.

For the dormer I think you'll need planning permission as you'll be changing the pitch of the roof (whereas PV normally follows the roof pitch). But I think the installs aren't too tricky as they can use ballasted tubs now. I'm attaching a link, but it's only for a visual idea and was the first I found after searching for 'flat roof pv panel tub' and I'm sure a better search will find you more options.

Going beyond 'your design brief' could you fit a few panels as a canopy over a back door, or even consider a PV pergola if (and I admit this is a strange question), but if you've ever fancied such a thing?

For leccy savings, that will depend on your daytime consumption. We use about 3,000kWh's pa, and have cut import by half, so save around 1,500kWh's x import price. I'd loosely guess that a 4.8kWp system as you describe would generate a similar amount to ours pa. due to better orientation, and SW is an excellent orientation for early evenings in the better 6 months of the year.

Zarch

Thanks Mart.... you may recognise the detail from a Navi thread.

The installer I spoke to said as long as the panels don't go higher than the ridge line (which they wont as the dormer roof is lower), then there should be no planning issues.

Martyn1981

Zarch wrote: »

Thanks Mart.... you may recognise the detail from a Navi thread.

The installer I spoke to said as long as the panels don't go higher than the ridge line (which they wont as the dormer roof is lower), then there should be no planning issues.

Do you want to apply for the multi-forum advice discount?

Interesting point about the dormer, which roof is the one that matters, I'd guess the installer is correct and it's the main roof, but I don't really know, hmm! :think:

Zarch

Spoke to the installer again about the dormer. Wife concerned about the finite life of the dormer roof explained to us by the builder when the loft conversion was done. Said it usually had around a 10 year lifespan and we are 5 years in now.

Installer said not really a problem as he could run longer cables to those panels so that they could easily be lifted, ie move the whole mounting frame/panel if needs be if and when the dormer roof needed replacing.

So that's positive...... steers me towards the 4.8kWp system as everyone says get as much as you can during the install.... although £6k+ is putting me off......... Does the fabled £1k per kWp actually exist? LOL.

am3n3

Hi Zarch, do your remaining quotes include scaffolding, EPC (if you need to obtain one) and labour?

I've just been quoted (details in a separate post) under £8k for a 4kW with SolarEdge & optimiser (instead of iBoost) + scaffolding and labour.

Zarch

am3n3 wrote: »

Hi Zarch, do your remaining quotes include scaffolding, EPC (if you need to obtain one) and labour?

I've just been quoted (details in a separate post) under £8k for a 4kW with SolarEdge & optimiser (instead of iBoost) + scaffolding and labour.

Yep, that's all in.

Zarch

Had a basic preliminary email quote from a local installer. No site visit yet, but all based on the measurements and info that I sent him across.

Says he doesn't think the dormer roof is a goer (contrary to what other installer says) do to wind issues as we could only secure them with ballast.

So he suggests 11 panels around 3KWp to 3.3KWp system and suggested a price of £5800-£6500 which he would confirm with a site visit to nail down the spec.
This was for a SolarEdge based system with all panels optimsed (for monitoring) rather than just specific panels. Based on 7 front roof, 1 porch, 3 rear extension.

He said it is possible to do the above system slightly cheaper by only optimising the rear roof and porch roof but you would not have any monitoring.

All in all I think that price is high in comparison to the other quotes so far. Might have to park that installer.

'North' installer is coming to do a site visit next week where we will hopefully get a more definitive quote.

I spoke to the 'South' installer yesterday about quoting for front, dormer and rear extension. I'm hoping they'll come out for a site visit.

Could be down to those two. Although £1k per KwP does seem unobtainable at this stage.

So really, i'm running out credible local installer options. Just don't fancy having any old cowboy turning up.

pinnks

If you are limited on the number of panels you could think about the higher efficiency one from firms like, I think, Benq or Sun Power (might have got the names wrong here). They had panels of up to 330Wp in 2013 when I was installing. They were more expensive but depends on the overall economics and the amount you can produce throughout the say. Just a thought...

Zarch

pinnks wrote: »

If you are limited on the number of panels you could think about the higher efficiency one from firms like, I think, Benq or Sun Power (might have got the names wrong here). They had panels of up to 330Wp in 2013 when I was installing. They were more expensive but depends on the overall economics and the amount you can produce throughout the say. Just a thought...

Thanks for that, maybe an option when I get formalised quotes after site visits to talk about panel prices and outputs.

The North installer has gone for Bisol 300w as he picked up I was conscious of getting best value from the install. Although i'm struggling to find an online price for those panels?

The South installer has offered LG 320w which seem to be about £220 per panel doing a bit of googling.

Like you say, finding that balance between panel output and cost is key. Plus, i'd like them to be all black panels if possible.

Zarch

Quick question about FIT and G83 limits.

If I went for a multi directional system with East, flat roof and South-West facing panels.

Say 11 x 300w SW (3.3kWh), 4 x 300w flat (1.2kWh) and 3 x 300w East (0.9kWh) = 5.4kWh..... but unlikely to ever reach max output across all panels due to shading and time of day factors.

If we were to stay under G83 limits only go with a 3.68kWh inverter what figure would go off for the FIT to base my payments on? 3.68kWh of the inverter? 5.4kWh of the panel total? or a figure based on PVGIS or MCS estimated outputs?

Thanks.