- This topic has 29 replies, 20 voices, and was last updated 6 years ago by gobuchul.
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Low-down on solar panels needed.
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BigJohnFull Member
We just had a bloke round from a solar panel company. Mrs BigJohn must have been cold called or something. Anyway, he gave us his pitch and did some calculations, which I thought were a teeny bit on the optimistic side.
It turns out our roof isn’t very good for the panels (1.5m x 1m I think) they’d only get 3 on there. However we have a large garage with a flat roof and they can get 9 panels on there, tilted at 20 degrees. They’ll also supply a “Volt Dr” thing which drops the voltage in the house to 216V, which “makes everything run better!” and a “Boiler Dr” which stops the combi boiler ripping up fivers.
The installation cost would be £9315. We’ll save, apparently, £50 a month GUARANTEED off our electricity bill (if we count in the refunds from the feed-in-tariff). This will rise to a saving of £77 a month in 8 years time.
He says the government feed-in-tariff is about 4p per kWh and OVO energy are supposed to give me 5p per kWh on top.Last year our electricity cost under £900.
Oh, and another thing – if we sell the house this will add £10,000 to the value!
I shan’t name the firm at this stage, but I’d be interested in real world experiences.
gobuchulFree MemberWhat is the total KW output of the panels?
As a rule of thumb, at the moment installation cost should be about £1 per W.
Not sure how much of that £9315 is for those “dr” things but it seems pretty expensive to me.
I asked the question on here a few days ago. http://singletrackworld.com/forum/topic/11kw-solar-system-cost
I should have 2 different quotes this week, so I can let you what I got quoted in a few days.
BigJohnFull MemberI think he was keen to avoid any awkward things. Like facts. But looking through what he left behind I guess each of the 9 panels is 250w, so 2250w in total. Those Doctor things are £600 each.
I can’t get my head around how dropping the voltage in the house to 216v is going to save money.
Fresh Goods Friday 696: The Middling Edition
Latest Singletrack VideosFresh Goods Friday 696: The Middlin...pistonbrokeFree MemberSo many things to take issue with.
£50 a month saving, is this year round or only the 4 months when there are enough sunshine hours in the UK?
Is your garage roof strong enough to support the panels and frames, they’re bloody heavy.
Adding £10k to the house value is bollox. They have no way of verifying this.
Cost seems very steep, I live in Spain and have recently installed a system which fully powers our house, 8 panels, 12 batteries, inverter and charger for under €9k.
I’d be very careful in believing any claims for solar in the UK climate.GreybeardFree MemberOver £9k for 2.2kW is definitely more than you should be paying for panels. 20º is a bit flat, so you won’t get the best efficiency out of them; which way does the roof face?
We’ve saved about £1100 in 6 years with 3.9kW; scaling that down to 2.2kW is just over £100 per year.
My rule is never to buy from anyone who comes to sell something, certainly without looking at other suppliers. The feed in tariff is set to give something like a 10 year payback period, if you take account of the FIT payments (for generating the power irrespective of what happens to it), the payments for selling power to the network and the savings. But if your panels aren’t facing the right way it could be more.
The Volt Dr is only going to help if your supply voltage is usually over 220V, and then only for some appliances. If it cuts the voltage from 230V to 220V, it’s effectively reducing the power of all your appliances, which saves electricity but means everything is less powerful. So a vacuum cleaner won’t suck as hard, but it will cost less to run for the same length of time. A kettle will take longer to boil, so won’t save anything.
Forget Volt Dr and this company’s sales pitch. If you want solar, find some reputable suppliers and see what they can offer.
JunkyardFree MemberSo a vacuum cleaner won’t suck as hard, but it will cost less to run for the same length of time
unless you use it for longer because its less powerful
steverFree MemberGo and find someone else that is well reviewed and well established. Bet it’s loads cheaper. The voltage reducers are a bit iffy. I have solar but there’s no way I’d spend that kind of money. Do some more digging, it’ll be dull and energy sapping but you’ll find someone decent hopefully 🙂
UrbanHikerFree Member“volt dr” and “boiler dr” set all the alarm bells ringing to me. I’d run a mile.
Ikea would be my first port of call.
squealerFree MemberI had an online quote off IKEA earlier today – £5.2k for 15 panels giving about 4.2kw. Slightly more expensive that the £1 per w referred to above but seems ballpark correct.
finephillyFree MemberI still don’t get why solar is installed in the uk. The payback time is biblical. The uk just isn’t sunny enough. plus you only get full efficiency when they’re pointed directly at the sun. you’d be better off with a solar hot water heater, changing the tariff and using less electric.
finephillyFree Memberlowering the voltage means you use less electric, basically. So your 3kw kettle runs at 2.8kw or whatever. the downside is your lights are dimmer, the kettle takes longer to boil and the washing comes out wet but hey you’re saving tuppence ha’penny.
igmFull MemberThere is evidence to show that reducing the voltage may reduce losses in the home.
I’m about to spend a few thousand pounds (probably tens of thousands) finding out if that’s true, and how and why it works. There are possible reasons.
So VoltDr may work, but I’m reserving judgment for now.carlosgFree MemberI didn’t pay for the 14 panels on my roof , went down the lease your roof space route with a co called’A shade greener’.
Mrscarlos is a full time housewife and does all the high energy usage during the day when its light. Since installation we have saved on average £50-£60 a month from our leccy bill.
Our house is SSW facing and gets sunlight for most of the day , even in winter we can usually run the washing machine and tumble dryer at the same time for free.
Denis99Free MemberWe have 4kw (16 panels) on our roof.
For the last 4 years the panels have produced a steady 4.1 MWh of energy.
The roof is totally south facing, with no shade affecting the performance.
We get monthly and seasonal variations, but it seems to even out over the year to the 4.1 MWh figure.
If you are at home alot, then the panels will power the at idle consumption with ease. The trick to reducing your electricity cost from the grid , is using the energy when the sun is out, most people are in work for the majority of the time.
Not sure what the feed in tariff is these days.
natrixFree MemberI’ve been very happy with our panels, even in the UK climate. To start with they were winding the leccy meter backwards, which was great until I had to agree to having a modern meter fitted. 🙂
Set the washing machine etc to run during the day, and the hot water boiler gizmo saves us money off the gas bill as well. Saving more than the estimates we were given. Neighbour uses his to charge his two hybrid cars.
stumpy01Full MemberWe’ve got quite a few houses in the road with solar, but these were put in when the feed-in tariff was a lot higher – I think it was something like 40p/kwh ages ago.
We had someone call up & come round about 2 years ago.
The system they were offering came with individual micro inverters for each panel, rather than one inverter covering them all – apparently the advantage of this is you are getting the maximum available power from each panel; with a single inverter you will be limited to the output of the lowest capacity panel – so if you have one dirty panel that is down 20% on power output, all the other panels will be throttled back to that one.
But, from the projected lifetime of the inverters, by the time I had paid off the finance on the panels, all of the inverters would need replacing which would mean more expense.
Even with the blokes highly optimistic output values, it was going to take something like 16 years before we started to get some money in our pocket – the whole thing seemed like a money making thing for them & nothing else.Looking online a few days later, I found comparable systems for about half the cost that he had quoted – although they only had single inverters, rather than the micro-inverter approach.
I think at the time the feed-in tariff was 12.5p or thereabouts. Since then, this has dropped to around 4p. I’d be amazed if you made your money back over the lifetime of the installation with that.
Another option (as someone mentioned above) is effectively renting out your roof space so someone else can plonk their panels on the roof. We didn’t bother looking into that option.
BigJohnFull MemberI’m pretty certain that the only people benefiting from the installation that Project Solar proposed would be Project Solar.
We just haven’t got much south facing roof; even the garage roof is shaded by neighbours’ trees. So it’s not worth doing for us.
GreybeardFree MemberThe Feed in Tariff has dropped very low, but it’s only one of ways you make/save money, so it doesn’t have a proportional effect.
My panels cost about £12k six years ago, when the FIT was about 45p. Typically I generate about 3MWh per year (not the 4.1 MWh that Denis99 gets as mine face SE) which is about £1450 in FIT, £50 in export and £180 saved by free electricity. So payback is 7 to 8 years – and the panels are guaranteed to produce 95% of their nominal power for 20 years.
If I bought a similar system now it might cost £4k, and I’d only get about 4p FIT (=£120/yr), but the export and free power would be unchanged, and the payback time would be 11 or 12 years. Longer, but still less than the life of the panels.
Although I lose out because my panels aren’t facing due S, I was lucky because panel costs had come down from £16k but FIT wasn’t cut until just after I had mine fitted.
gobuchulFree MemberOkay.
1st quote in. For a 11.4 KW system, 40 panels and 2 inverters, including fitting, scaffolding, vat etc. £12,915.
Without the VAT and scaffold, £11,500, so pretty much £1 per watt.
enfhtFree MemberChinese production is much cheaper but the UK are currently obliged to buy German tech.
kcalFull MemberI did have a look a little while back at various solar options but being in NE Scotland, and the way the house and shed faced and were inclined, it wasn’t going to work out.
A former colleague has built a house in the last few years, so obviously installation costs can be factored in more easily. He is very methodical (!) and did a set of spreadsheets on cost/ benefit of solar PV vs thermal, and came to the conclusion that – for the roof space he had – it was better to maximise the solar PV, use the power to heat a double or triple insulated hot water immersion tank, and use *that* to generate the hot water. I guess saves on plumbing on the roof and so on, plus probably took advantage of the FIT tariff at the time..
finephillyFree Membersolar hot water is easy. just get a radiator, paint it black and stick it on the roof with a pump to your bath!!
igmFull Membergobuchul – do make sure at that size that you are applying under the correct connections scheme – it sounds G59, not G83. There are only minor differences, but it’s worth keeping yourself legal with regard to ESQCR Reg 22 (16A per phase at 230/400V)
blurtyFull MemberWhat everyone tends to forget with PVs is that efficiency drops off as they reach the end of their lives, and that PVs will have to be disposed off as hazardous waste – expensive! (They contain Cadmium Telluride, very expensive to deal with – assume a £2k – £5k disposal cost, at today’s prices)
damascusFree MemberI’m with a Shade greener. A fantastic company to deal with. Recently my inverter broke as my system had produced over 18000kw (I think) it’s been installed since around June 2010. They contacted me, booked it in and replaced it straight away. It would have cost me over £800 to repair this.
As of today it’s done
Generated: 19444kWh
CO2 Saved: 8.36t
At the moment it’s generating between 10 and 16 kw a day.Based in West Yorkshire. It’s a 3kw system. Facing south or south east ish.
I’ve had a unit fitted to my immersion heater like this
I’ve had pretty much free hot water for 90% of the year even in winter. It takes around 2kw to reheat to full after a shower and 4 after a bath.
I really don’t understand why you would have a hot water system when you can use electric to heat the water?
My electric bills reduced by around 60%. It would be more if it was used more during the day.
Even with a very efficient house I still pay electric as I get charged a connection fee. I think this is about 20p a day? Might be wrong. My current electric bill is around £2.40 a week.
I really want to buy a battery system but I’ve not really seen a good set up at a realistic price yet.
As for making your house worth £10000 more? Possibly, if someone wants solar power and is prepared to pay for it?
Personally I’d rather pay £10000 less and get solar panels with free electric and hot water.
Try and get a company to pay for the panels and pay £10000 off your mortgage, it’s a far better saving.
A Shade greener is a good company to deal with (if they are still fitting panels?)
Also a Shade greener have in their contract that they will dispose of the solar panels at their cost or leave them if I want. With the government money paying for the feed in they should still be solvant and not disappeared by 2035. (hopefully)
gobuchulFree Membergobuchul – do make sure at that size that you are applying under the correct connections scheme – it sounds G59, not G83.
I have a 3 phase supply, the limit is 3.68kw per phase so I sit withing the limit.
igmFull MemberAt 11.04kW three phase you are entirely correct.
I thought you’d said 11.4kW previously – where you are technically G59 but you just inform the DNO and 999/1000 times they say don’t worry about it – thereby keeping you legal.
As you were then.
PS – in my previous role it was my guys you would (location dependent) have informed. If I can help PM me.
EdukatorFree MemberI really don’t understand why you would have a hot water system when you can use electric to heat the water
Because I DIY built the whole system myself with big pipes, thermosyphon so no pumps of sensors to go wrong and it provides all our hot water for 5-6 months then works as a pre-heater for the normal immersion heater for the rest of the year, the washing machine is fed direct on the fill cycle. In terms of energy recovered/m2 it does better than PV. The system has already paid for itself after 10 years.
Our 13 solarworld panels produced 3450kWh this year, that’s the best yet due to a sunny Spring. 26990kWh since installation. No signs of reduced efficiency after eight years. About double our domestic consumption, we’ve recently added an electric car but will still produce more than we consume.
SW France, but if you compare with figures quote above there’s not a huge difference per panel compared with the UK.
gobuchulFree Member2nd quote in, 42 panels 12kw. £12,732
Again pretty much £1 per KW.
Hard to choose installer. Both were very easy to deal with, no hard sell at all. Both established and fairly local.
Also, it’s very hard to get any information on which panels are better than others, there seems to be a big difference between inverter cost as well.
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