Solar panel installation & snake oil question.
Discussion
After a few hefty bills, we have been looking at various solar panel options. I have a good freind in the trade who has given me a an idea of what to look for and what questions to ask, however he is many miles away but would otherwise be my first choice for installation.
I've got a couple of local quotes - two of them are regular electricians who also install panels, but one of them is a huge corporate specialist type of company. The regular guys came around with a compass and tape measure, look at the rafters in the loft, checked for tree shade and stuff, then told me about different types of panels and inverters and will come back to me with a price.
The third one has been a lot more "salesy". First off, spent 20 minutes explaining why they are #1, all the accreditation they have, they underwriting criteria they fulfil, the world record panels they use and lots of other sell. He then went onto to take about price comparison websites and transferring suppliers, and then mentioned a thing called a "Voltage optimiser".
This is a device that reduces the voltage from an indicated 244v at the sockets to 220v - saving us £x per year allegedly. Now I'd never heard of this before, so I was in no position to question or argue the physics behind it, but when he said they retail at £650 but they can install it for free as part of the deal I got itchy about the rest of their offerings.
The other concern about this company is that I wanted a cash price quote, but the finance seemed to be mandatory, and at 9.9% APR. I know I can get funding much cheaper than that, hence why I wanted the cash price equivalent.
Finally, the 4kw system that has been quoted by the other two are around £5k-£6k installed depending on inverter and panel type. This system was quoted to me at £9500 for a 5.3kw, which I was led to believe that 4kw was the maximum domestic application, but then when I looked at the small print this morning, the total price including finance is £16k. All the price comparisons during the sales pitch were based on the cash price, but if there is £7k of interest to pay on this, then the figures he was quoting are not going to be accurate.
So, Voltage optimiser - snake oil or not?
What is the maximum Kw that a doemstic system is allowed to generate, 4Kw or higher?
And without directly naming the company in question, has anyone had a similar experience with a solar Project like this?
I've got a couple of local quotes - two of them are regular electricians who also install panels, but one of them is a huge corporate specialist type of company. The regular guys came around with a compass and tape measure, look at the rafters in the loft, checked for tree shade and stuff, then told me about different types of panels and inverters and will come back to me with a price.
The third one has been a lot more "salesy". First off, spent 20 minutes explaining why they are #1, all the accreditation they have, they underwriting criteria they fulfil, the world record panels they use and lots of other sell. He then went onto to take about price comparison websites and transferring suppliers, and then mentioned a thing called a "Voltage optimiser".
This is a device that reduces the voltage from an indicated 244v at the sockets to 220v - saving us £x per year allegedly. Now I'd never heard of this before, so I was in no position to question or argue the physics behind it, but when he said they retail at £650 but they can install it for free as part of the deal I got itchy about the rest of their offerings.
The other concern about this company is that I wanted a cash price quote, but the finance seemed to be mandatory, and at 9.9% APR. I know I can get funding much cheaper than that, hence why I wanted the cash price equivalent.
Finally, the 4kw system that has been quoted by the other two are around £5k-£6k installed depending on inverter and panel type. This system was quoted to me at £9500 for a 5.3kw, which I was led to believe that 4kw was the maximum domestic application, but then when I looked at the small print this morning, the total price including finance is £16k. All the price comparisons during the sales pitch were based on the cash price, but if there is £7k of interest to pay on this, then the figures he was quoting are not going to be accurate.
So, Voltage optimiser - snake oil or not?
What is the maximum Kw that a doemstic system is allowed to generate, 4Kw or higher?
And without directly naming the company in question, has anyone had a similar experience with a solar Project like this?
Do not get a voltage optimizer unless you want dim lights, a kettle that takes an age to boil, toast which is never quite toasted and cold showers!!
I worked in the industry for a few years designing the electrical schematics for solar farms before the government cut the FITs. To me, the first guy you spoke to sounded like he knew his stuff whereas the second chap just wanted to get as much money out of you that he possibly could have whilst making it sound like a good deal!
I'm not sure what the maximum size system you can get these days on a domestic roof is but 4kW sounds about right to me. I'm sure a quick google search would produce the answer.
If I were you though I wouldn't even bother with a system these days. I'm not sure what the rates are these days but I know they are extremely low compared to what they used to be. Seems like a lot of ball ache and expenditure for hardly any return. Your better off sticking you 5-6k into a savings...
I worked in the industry for a few years designing the electrical schematics for solar farms before the government cut the FITs. To me, the first guy you spoke to sounded like he knew his stuff whereas the second chap just wanted to get as much money out of you that he possibly could have whilst making it sound like a good deal!
I'm not sure what the maximum size system you can get these days on a domestic roof is but 4kW sounds about right to me. I'm sure a quick google search would produce the answer.
If I were you though I wouldn't even bother with a system these days. I'm not sure what the rates are these days but I know they are extremely low compared to what they used to be. Seems like a lot of ball ache and expenditure for hardly any return. Your better off sticking you 5-6k into a savings...
I think you're allowed more than 4kW, but it depends on the electricity provider as to whether they'll let you connect it up. Also dependant on your roof size - average 4kW system has 16 panels.
Most systems are around 4kW and prices seem to be around £5-7k.
Might be worth looking for a good local independent, and also check that they're providing quality branded panels and inverter.
As for Voltage optimisation I know it works on larger non-domestic installations - a well know supermarket spent a ton of cash installing VO in most of there stores a few years back. Speaking to their estates guys apparently it saved them a significant amount.
Domestically it depends - what sort of load make up do you have in the house?
If you've already got LED lighting then there'll be virtually no saving on that, if you reduce the voltage to a kettle it'll take longer to boil and an immersion heater will take longer to heat your hot water so savings there could be negligible.
Most systems are around 4kW and prices seem to be around £5-7k.
Might be worth looking for a good local independent, and also check that they're providing quality branded panels and inverter.
As for Voltage optimisation I know it works on larger non-domestic installations - a well know supermarket spent a ton of cash installing VO in most of there stores a few years back. Speaking to their estates guys apparently it saved them a significant amount.
Domestically it depends - what sort of load make up do you have in the house?
If you've already got LED lighting then there'll be virtually no saving on that, if you reduce the voltage to a kettle it'll take longer to boil and an immersion heater will take longer to heat your hot water so savings there could be negligible.
Thanks on the replies - Voltage Optimiser seems to work in certain circumstances, but since we already have low voltage everything, and all our cooking appliances are electric, I think it it will be more of a hinderance than help.
Still not sure about the 5.3kw system though - the more I look into this larger array, the more I think we would be throwing money at something for no return. And the finance offered by the company doesn't stack up at all for us.
What I can't deny is that solar would benefit us based on our usage, and looking at the savings through reduced electric bills alone, I can make the installation pay for itself within 4-5 years.
Still not sure about the 5.3kw system though - the more I look into this larger array, the more I think we would be throwing money at something for no return. And the finance offered by the company doesn't stack up at all for us.
What I can't deny is that solar would benefit us based on our usage, and looking at the savings through reduced electric bills alone, I can make the installation pay for itself within 4-5 years.
S11Steve said:
I can make the installation pay for itself within 4-5 years.
I'm shocked (excuse the pun!) at this. I genuinely didn't realise that the gains would be as great as this. In that case go ahead but I'd give that 'sales' guy you mentioned a wide birth.Let us know what you decide and keep us updated!
Our electric bill is close to £2k per year, in theory the panels with correct placement will provide half of our consumption, with a bit of feed-in.
A lot of the numbers are speculative to a degree, based on certain number of sunny days and such like, but by splitting the panels across front and rear aspects of the roof, we can increase efficiency throughout the day, so at least half the panels will be in full sun (when we get it!) at any one time.
The roof is physically big enough to have a lot more panels, but there is a point of diminishing returns as more panels and bigger inverters would be needed, and the grid will only cope with so much current.
A lot of the numbers are speculative to a degree, based on certain number of sunny days and such like, but by splitting the panels across front and rear aspects of the roof, we can increase efficiency throughout the day, so at least half the panels will be in full sun (when we get it!) at any one time.
The roof is physically big enough to have a lot more panels, but there is a point of diminishing returns as more panels and bigger inverters would be needed, and the grid will only cope with so much current.
S11Steve said:
Our electric bill is close to £2k per year, in theory the panels with correct placement will provide half of our consumption, with a bit of feed-in.
Remember there's typically a big mismatch between when you want electricity (when it's cold and/or dark) and when solar power will provide it (when it's hot and sunny)I'd spend some time (and a little money on a logging unit) monitoring exactly what (and when) is using most power in your home. And also make sure you're on the right tariff
S11Steve said:
Our electric bill is close to £2k per year, in theory the panels with correct placement will provide half of our consumption, with a bit of feed-in.
A lot of the numbers are speculative to a degree, based on certain number of sunny days and such like, but by splitting the panels across front and rear aspects of the roof, we can increase efficiency throughout the day, so at least half the panels will be in full sun (when we get it!) at any one time.
The roof is physically big enough to have a lot more panels, but there is a point of diminishing returns as more panels and bigger inverters would be needed, and the grid will only cope with so much current.
Isn't having part of a panel (in this case the part of the roof not getting sun) a no no? http://www.solarchoice.net.au/blog/partial-shading...A lot of the numbers are speculative to a degree, based on certain number of sunny days and such like, but by splitting the panels across front and rear aspects of the roof, we can increase efficiency throughout the day, so at least half the panels will be in full sun (when we get it!) at any one time.
The roof is physically big enough to have a lot more panels, but there is a point of diminishing returns as more panels and bigger inverters would be needed, and the grid will only cope with so much current.
Apologies if you've already taken this into account.
As alluded to in kapiteinlangzaams thread, we are also looking at the panels with individual optimisers on them, so if one is in shade, it won't pull down the other panels in the string. Most of these systems do have the monitoring app too.
Which is also linked to having front and rear panels - the sun rises at the front of the house, and sets at the rear, but we have a gable end to the south so can't have panels on that side. We've been learning about how to maximise the PV generation, so putting washer and dryer on during the day for example, rather than saving it all to the weekend. Likewise, both ovens are electric, and the hob is induction.
So in theory, we can breakeven by year 5, but it's a long term house and generating our own electric has got to be future-proofing it to a degree.
Which is also linked to having front and rear panels - the sun rises at the front of the house, and sets at the rear, but we have a gable end to the south so can't have panels on that side. We've been learning about how to maximise the PV generation, so putting washer and dryer on during the day for example, rather than saving it all to the weekend. Likewise, both ovens are electric, and the hob is induction.
So in theory, we can breakeven by year 5, but it's a long term house and generating our own electric has got to be future-proofing it to a degree.
S11Steve said:
Our electric bill is close to £2k per year, in theory the panels with correct placement will provide half of our consumption, with a bit of feed-in.
A lot of the numbers are speculative to a degree, based on certain number of sunny days and such like, but by splitting the panels across front and rear aspects of the roof, we can increase efficiency throughout the day, so at least half the panels will be in full sun (when we get it!) at any one time.
The roof is physically big enough to have a lot more panels, but there is a point of diminishing returns as more panels and bigger inverters would be needed, and the grid will only cope with so much current.
A 4kW system or even a 7kW system will never cover half your usage surely?? Are you in the UK? For around 4-5 months a year it wouldn't really even be producing much...A lot of the numbers are speculative to a degree, based on certain number of sunny days and such like, but by splitting the panels across front and rear aspects of the roof, we can increase efficiency throughout the day, so at least half the panels will be in full sun (when we get it!) at any one time.
The roof is physically big enough to have a lot more panels, but there is a point of diminishing returns as more panels and bigger inverters would be needed, and the grid will only cope with so much current.
Forgive me if I'm wrong but whats your maths here?
welshjon81 said:
S11Steve said:
Our electric bill is close to £2k per year, in theory the panels with correct placement will provide half of our consumption, with a bit of feed-in.
A lot of the numbers are speculative to a degree, based on certain number of sunny days and such like, but by splitting the panels across front and rear aspects of the roof, we can increase efficiency throughout the day, so at least half the panels will be in full sun (when we get it!) at any one time.
The roof is physically big enough to have a lot more panels, but there is a point of diminishing returns as more panels and bigger inverters would be needed, and the grid will only cope with so much current.
A 4kW system or even a 7kW system will never cover half your usage surely?? Are you in the UK? For around 4-5 months a year it wouldn't really even be producing much...A lot of the numbers are speculative to a degree, based on certain number of sunny days and such like, but by splitting the panels across front and rear aspects of the roof, we can increase efficiency throughout the day, so at least half the panels will be in full sun (when we get it!) at any one time.
The roof is physically big enough to have a lot more panels, but there is a point of diminishing returns as more panels and bigger inverters would be needed, and the grid will only cope with so much current.
Forgive me if I'm wrong but whats your maths here?
welshjon81 said:
A 4kW system or even a 7kW system will never cover half your usage surely?? Are you in the UK? For around 4-5 months a year it wouldn't really even be producing much...
Forgive me if I'm wrong but whats your maths here?
We're in Sheffield, and they are based on using the figures from two installers so far, and third still to come back on a price. The savings figures they are quoting are around £900-£950 per year, between savings on usage and export. The generation level is 2850kw - the quotes are at home so haven't got the exact figure to hand.Forgive me if I'm wrong but whats your maths here?
Do these seem right, or am I being sold a dummy?
S11Steve said:
We're in Sheffield, and they are based on using the figures from two installers so far, and third still to come back on a price. The savings figures they are quoting are around £900-£950 per year, between savings on usage and export. The generation level is 2850kw - the quotes are at home so haven't got the exact figure to hand.
Do these seem right, or am I being sold a dummy?
I have to be honest Steve they sound quite far fetched to me. I'm not entirely sure but I would say savings of around £300-£400. I've been out of the game a good few years now but only in the 'boom' times would you be looking to making around that much.Do these seem right, or am I being sold a dummy?
http://www.energysavingtrust.org.uk/domestic/solar...
Have a look here.
Woody said:
A guy at work had PV installed last year, they guaranteed 3 MW and he's generated 3.6 MW in the last year.
That's a big roof, considering the typical nuclear plants in this country only generate 600MW.KW (and MW) hours, please. Otherwise it's like saying your car goes from 0-60 miles in 7 seconds.
(PH : Pedantry matters!)
silentbrown said:
Woody said:
A guy at work had PV installed last year, they guaranteed 3 MW and he's generated 3.6 MW in the last year.
That's a big roof, considering the typical nuclear plants in this country only generate 600MW.KW (and MW) hours, please. Otherwise it's like saying your car goes from 0-60 miles in 7 seconds.
(PH : Pedantry matters!)
Edited by FarmyardPants on Thursday 26th May 18:21
The FIT dropped from 16 something pence a KW to 4p so the actual returns from the FIT will not be worth the outlay to be honest. The main savings will be from using the electricity the panels produce.
There was a time when i planned on pulling the trigger on 12 houses in my portfolio and the returns would have been well worth the outlay but i fannied about and before i knew it the FIT had been slashed. I friend of mine could install a 3.5k system for £4500 with an average return of £750 per annum per roof using the lower estimates.
There was a time when i planned on pulling the trigger on 12 houses in my portfolio and the returns would have been well worth the outlay but i fannied about and before i knew it the FIT had been slashed. I friend of mine could install a 3.5k system for £4500 with an average return of £750 per annum per roof using the lower estimates.
The "early bird special" (pre March 2012 if memory serves) FIT rate is now around 49p per kWH for <= 4kW systems, plus a small amount of deemed export. Well worth doing back then, although the installation cost was ~x2 what it is now.
Ours was installed in Nov 2011 and is now in urgent need of a clean, but that's for another thread..
Ours was installed in Nov 2011 and is now in urgent need of a clean, but that's for another thread..
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