Solar quote confusion

Woby_Tide

Apologies, have been reading up but still fairly new to all this. Have contacted a couple of online companies and also a couple of local ones who have done site visits and I'm kind of surprised at the difference between what they are all suggesting is suitable. Even down to the placement on the roof some seem to be pushing the limits/boundaries whilst some have been way more restrained in what and how close to the edge they would use.

We currently use about 8000 kWh per annum including an EV and I see the benefit of the battery.

All the companies seem to have OK reviews when I've looked up on various sites, warranties are as expected with most of the options but I just wondered if this is normal to have a such a spread of suggestions for the same house and the same requirements or am I missing something? Had one also suggest battery only due to their view of the roof being unsuitable due to multiple pitches and directions.

Cost	System Size kw	Panels	Size w	kWh pa	Battery kWh	Battery	Inverter kw	Inverter
£ 14,000	11	24	465	9000	15	SolaX TP-HS50E	8	SolaX X1-IES
£ 15,000	11	24	465	9000	20.5	SolaX TP-HS50E	8	SolaX X1-IES
£ 15,500	12	26	465	9700	16.5	GoodWe8.3 G20	10	Goodwe GW10K
£ 17,000	12	26	465	9700	25	GoodWe8.3 G20	10	Goodwe GW10K
£ 15,000	10	21	480	8000	18	Sigenergy Bat10.0	10	SigEnergy EC 10
£ 16,250	12	25	480	9500	18	Sigenergy Bat10.0	10	SigEnergy EC 10
£ 12,000	7	14	520	5500	16	GoodWe8.3 G20	8	Goodwe GW8K
£ 6,400	4	8	495		5	Dyness G2	3.6	Solis S5-EH1P
£ 7,400	4	8	495		10	Dyness G2	3.6	Solis S5-EH1P

blanched_jelly

Did some of the installers do desktop vs site surveys?

Jemma01

Not unusual, each designer will try to meet the requirements as they see fit. Some will look at your overall area generation (how much sun on average the area gets) and think you can save money and be self sufficient with fewer panels, others will try to maximise the space on your roof to generate more so you can sell more and get a revenue out of it. Some will try to sell you as much as possible to make money for themselves!

I would drop anything less than 8kw inverter out of the question, I can't see those 2 being sufficient if you're charging your car and washing clothes and the oven+extractor on; you'll probably still need the grid even if the battery is full.

Octopus for me suggested 21 panels over north and south facing. I thought north was waste of money as it's not facing the sun, and apparently will probably only generate 40% of the south facing, so I dropped that. Another installer suggested 14 panels on the south facing with two sigenergy batteries, I like that, but my space couldn't fit the battery and allow a wheelie bin through, if I wanted EV charging, I would have gone for this but I have no EV plans. Then the 3rd suggested 16 panels south facing with 1 tesla battery (which are thinner in size) after coming to the house and measuring, so I went for it. I worked out that for my usage in winter I might need a battery extension pack, but I'll decide when I get there and try it out for the year. Not rushing to overspend. Also I'm more interested in self sufficiency than revenue. (The mismatch in panel colour is under investigation 🤔)

Screwdriva

https://forums.moneysavingexpert.com/discussion/comment/81975842#Comment_81975842

That looks like a lovely end result - very efficient use of every inch of roof real estate.

Jemma01

https://forums.moneysavingexpert.com/discussion/comment/81975874#Comment_81975874

It is 😍 I'm very pleased with it. It generates on average 53kw/d, 75% is munched by the grid for free 🫨

And for what I paid, much better value offer than what's in OP's list.

Screwdriva

https://forums.moneysavingexpert.com/discussion/comment/81975883#Comment_81975883

I am so glad you are pleased - makes what I do worth the effort. I hope you'll update your post with additional details of the end result someday!

I am sure you are in the process of onboarding to Octopus Energy's export tariffs?

QrizB

75% is munched by the grid for free 🫨

Who is your electricity supplier? Unless they're one of the tiny ones you should be able to get paid for export ...

Jemma01

https://forums.moneysavingexpert.com/discussion/comment/81975889#Comment_81975889

I am yes 💃

They need to backdate the payment 😅. It's octopus @QrizB

Screwdriva

https://forums.moneysavingexpert.com/discussion/6665559/solar-quote-confusion

Apologies in advance for my directness, but none of the quotes shared impress. Most comprise of low end component brands from the Far East with hardly any track record… or worse. Sadly, this is a common tactic employed by greedy installers who prioritize profit maximization over the customer's long term interests.

It's impossible to be 100% sure without measuring the roof via survey, but assuming the highest # of 26 panels can fit on all South/ West/ East aspects (and none facing North), the installers I use to help other forums members have offered:

26 X Eurener 515W Bifacial panels (30 year warranty, Made in the EU since 1997)
1 X Tesla Powerwall 3 13.5kW with Gateway 2 (Built in inverter size is can be programmed upto 11kW)

~£14K installed with 10 year workmanship warranty, G99 and bird netting. If for any reason the # of panels needs to be reduced, just subtract £200 per panel.

Hope this helps provide perspective. Depending on where you are located, I am confident you can do much better!

P.S. This was just released on Sigenergy, as a great example.

Reed_Richards

@Screwdriva seems to be very keen indeed on Tesla but I have a Goodwe inverter and it has worked quite well for me since 2019, although the WiFi module failed and was replaced under warranty. I don't think Tesla were marketing their home batteries and inverters back in 2019; if I'm right Goodwe certainly has a longer track record. Goodwe inverters are not that common in the UK but I they gather are a popular choice in Australia. .

Woby_Tide

https://forums.moneysavingexpert.com/discussion/comment/81975902#Comment_81975902

Thanks for the feedback, the SigEnergy stuff I had seen people sort of recommend and GoodWe was a new one to me so will see what I can find out. Interesting that everyone has shied away from quoting a Tesla PW citing the cost.

We're mid-South Coast near the New Forest so if you do have any installer suggestions over this way that would be great as can see those prices you mention would be much better value