Advice?

[bk81]

Hi Everyone,

I've not been in this part of the forum before, but, my Mum is thinking of getting panels on her roof and has had a company called Solarson.

They have quoted £9450 for 10 panels (250w) and will also reduce the voltage to 220v, apparently saving her 17% on her bill. They gave an example of 3 hours daylight a day giving a £500 saving a year on electricity bills also.

She wants me to give her some questions to ask for when the surveyor comes out.

Also her loft is converted, I assume the inverter would usually go in there and then cables run from the loft to the cut out fuse/ consumer unit (under the stairs on the ground floor of a semi detached)?

Let me know if you need any more info for a better picture...

Cheers folks!

 

[Gavin A]

no questions, just do not let their man in their salesperson in the house.

A 2.5kWp system should be in the region of £5-6k.

They'll be using a hard selling salesman not a proper surveyor, and your mum is in severe danger of being ripped off.

 

[infinity]

^^^^ As Above! In fact our budget range on a concrete roof were just under £5K!

 

[bk81]

Cheers guys,

Would her having a converted loft make it any more expensive?

Any ideas of the average annual profits from 10 panels?

 

[infinity]

Your best asking if any of the forum members cover that area and they could visit and explain it all.

 

[telectrix]

gosh-boggling advice from those^^^^^^ posts. you buy a car from a salesman, not PV. the guy will be on c. 25%commission and they won't get rid of him till they've signed on the dotted.

 

[bk81]

I've take infinity's advice, I'll get her to get at least 3 quotes before choosing.

 

[jonnyboy1]

I wonder how there "salesman" measured the voltage to suggest & quote for voltage optimisation.

 

[Gavin A]

I've take infinity's advice, I'll get her to get at least 3 quotes before choosing.

tbh, Personally I reckon even this advice is a waste of lots of peoples time and won't in any way guarantee you'll end up with the best option.

look around for pricing, ask around for recommendations from friends who have it, check out websites of local companies that have been recommended, then ask your preferred option or 2 for a quote, if it's in the ball park pricing you're expecting and they provide a decent proposal then there's no point wasting everyones time by getting a couple of random companies in just to make up the numbers.

Whatever you do, definitely do not use the websites that promise to get you 3 quotes for you, as a lot of the better priced, better quality companies will not use them, so you're likely to end up with a choice of 3 over priced companies quoting. eg a friend of mine in London used one, and got 3 quotes around £12k for systems we were charging around £7-8k for at the time, so we ended up going down to do it for him instead.

 

[bk81]

That's what I said to her Jon, most installs I do aren't exactly 240v, I think the lowest has been about 228v, in which case the savings would be different. That's why I came on here, I install DC power supplies in Data centres so is a bit different to PV so need some advice so she doesn't get ripped off.

Sounds like a proper sales pitch and it also sounds like it's worked on her!

 

[bk81]

I won't be going through websites like that Gavin, I'll be getting a few quotes and not necessarily going with the cheapest. It'll be whoever gives the best value for money I would think.

Just trying to get a ballpark figure for the type of installation, obviously an exact quote could only be given once it has been surveyed. I am a spark though, and won't be as easily fooled with jargon as a woman in her 60s living on her own.

 

[FB.]

They have quoted £9450 for 10 panels (250w)

Far too expensive. I paid less than that for 3.75kWp over a year ago.

 

[FB.]

From a 2.5kWp system with good orientation (South-ish, 30-35 degree pitch) and no shading, I would expect about 2400kWh per year of generation.
That's worth £424 in FiT and export payments.
If inflation is 4% per year, that becomes £627 per year in ten years time and perhaps £929 in 20 years time when the FiT payments will cease.

About one-third of the power may be able to be used in-house: 800kWh, which would cost about 13p per kWh to have bought from the grid.
That's worth £104.
If electricity prices double in the next ten years (+7% per year), that becomes £208 per year saving. Perhaps double that again in 20years time: £416.

So the solar is likely to "earn" a combined FiT plus bill savings of £528 per year now, and perhaps £835 per year in ten years time and perhaps £1345 in its last FiT-eligible year (after which only the £416 bill savings and a token-gesture export tariff will apply).

Is that worth £9500 upfront? Unlike cash in the bank, it can't ever be withdrawn so the money must be "written off" - and maybe even some of the "profits" put aside for longer-term maintenance and repairs.
It's not worth £9500 to me. £6000 maybe. I think you can get it for even less than £6000 and still have a job well done.

My usual 1/20th "depreciation charge" (provision for repair/replacement and inability to cash-out) gives a loss of £475/yr on the value of the system (over 20yrs) and this offset by £528 profits per year now, £835 in ten years time, and £1345 in 20years time.
Return on investment: £53/yr now (0.6%), £360/yr in ten years time (3.8%) and £870/yr in twenty years time (9.2%).
Take the average of the "now" and the "20yr" rate of return and it's 4.9% on the initial outlay, allowing a 1/20th provision for repairs/replacement.

Rates of inflation and electricity prices are just vague guesses, since the future is unknowable.

 

[Vegelen]

I'll be getting a few quotes and not necessarily going with the cheapest.
It'll be whoever gives the best value for money I would think.

Find a Solar installation company with a good reputation that will install good quality, reliable solar hardware at a fair price - £5250 - £5500?

Dont go for the cheapest quote. Ultimately you get what you pay for.

Make sure you choose an efficient good quality inverter i.e SMA
Easy to repair / very reliable.

Choose good quality inexpensive solar panels:
i.e Suntech STP-20/Wd+ / H J Solar HJM250M-32 (Black) or alternative.

Glasgow has lots of overcast weather, so make sure you choose solar panels that generate well in low light conditions.

I'd expect a 2.5KWh system to generate between 2050 - 2150 KWh in central Glasgow on an optimal south facing roof, inclined at 35 degrees with no shading.

PVGIS Estimates 1950KWh:

http://re.jrc.ec.europa.eu/pvgis/apps4/pvest.php

FB's 2400 KWh stated figure is more optimistic as he lives in Cambridgeshire.

In North Cheshire (NW England), a 3KW SMA 3000TL, Suntech solar system generated

2575 KWh in the last calendar year.

Orientation due south, no shading, solar panels inclined at 32 degrees.

NB: Suntech solar panels have outperformed Panasonic HIT's by 4.5% in our region in the last 365 days.

 

[FB.]

Glasgow has lots of overcast weather, so make sure you choose solar panels that generate well in low light conditions.

I'd expect a 2.5KWh system to generate between 2050 - 2150 KWh in central Glasgow on an optimal south facing roof, inclined at 35 degrees with no shading.

FB's 2400 KWh stated figure is more optimistic as he lives in Cambridgeshire.

Yes, my figures are "best case scenario".

I've seen credible arguments which suggest polycrystalline panels perform better than monocrystalline in cloudy environments.
This is not entirely unbelievable, since mono panels are smaller and tend to respond best to light straight at them, while poly tend to be both larger, and have a more irregular crystal structure which may better absorb light from all directions (i.e. an all-over-white-cloud-sky) but less well able to absorb light from one direction (i.e. direct sunshine).