And I would expect @DaveNN to have paid VAT on his combo where as who ever quoted you should be VAT free. Yet again goes to show that where the government funding goes...To top it off most are just interested in flogging you into a g98 installation as to milk it even more (faster whilst the grant exists)
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Solar Panels UK - is it worth it?
- Thread starter jdwuk
- Start date
And I would expect @DaveNN to have paid VAT on his combo where as who ever quoted you should be VAT free. Yet again goes to show that where the government funding goes...To top it off most are just interested in flogging you into a g98 installation as to milk it even more (faster whilst the grant exists)
I know of one supplier who will give you MCS etc for £400.Yep...Ive given up on these glorified installers... I'll just get on with it, save a load more money and and burn in hell as far as some are concerned... I've tried
Yes not an installer but a supplier.
Got a 7.2 system with 3.68 inverter (max in Northern Ireland) and DC battery. It's great to see the sun energy go into powering the car. A word of warning though. There seem to be some issues with certain systems communicating with DC home batteries so a charger like Zappi can not tell the difference between solar and battery production and will drain the home battery charging the car. AC home batteries do not have this problem as their output can be measured with a CT clamp.
WannabeOwner
Well-Known Member
I have a thermal store ... seems to me that it allows the "boiler" to run for longer, and cycle-less, which ought to help efficiency. With Heat Pump can also run the store to "minimum" towards the end of the day, and set it to max during Off Peak to store some energy.
I find that the store means the heating gets going sooner - I have a large house, and there is a huge slug of cold water which returns (from Rads) to "boiler" when the thermostat kicks in ... the accumulator smooths that, whereas a boiler would have to lift the temperature of the cold water, and likely deliver at lower temperature until the whole circuit was warm.
I had a go with the Energy Saving Trust calculator - hopefully reasonable representative
4 kWp system:
South = 3,739 kWh / year
East = 3,173 kWh / year
West = 3,173 kWh / year
So East or West would be 15% less, whereas East plus West is 70% more
phil4
Member
Sorta... you're comparing a 4kWp system (lets say 10 panels).
If you fit 5 on the east and 5 on the west you'd still get 15% less than 10 on the South.
But if you fit 10 on the east and 10 on the west, you get 70% more, but you've also fitted 20 panels, not 10, and all the extra cost that goes with that.
ie. you're not comparing apples with apples on that 70% more figure.
That's exactly my reasons for looking at this route.I have a thermal store ... seems to me that it allows the "boiler" to run for longer, and cycle-less, which ought to help efficiency. With Heat Pump can also run the store to "minimum" towards the end of the day, and set it to max during Off Peak to store some energy.
I find that the store means the heating gets going sooner - I have a large house, and there is a huge slug of cold water which returns (from Rads) to "boiler" when the thermostat kicks in ... the accumulator smooths that, whereas a boiler would have to lift the temperature of the cold water, and likely deliver at lower temperature until the whole circuit was warm.
I had a go with the Energy Saving Trust calculator - hopefully reasonable representative
4 kWp system:
South = 3,739 kWh / year
East = 3,173 kWh / year
West = 3,173 kWh / year
So East or West would be 15% less, whereas East plus West is 70% more
East / West panels are very vulnerable to shading during winter months. Definitely bear this in mind and try one of the apps showing where the sun sits at noon in December / January. I have 4kW split between E/W and it doesn't really do very much in Dec/Jan (maybe 2kWh max on a sunny day on the winter solstice, up to 4kWh by end of Jan).
My dad has south facing panels and is consistently hitting his inverter limit of 6kW in January, and has generated over 1.5GWh in the last six months.
My dad has south facing panels and is consistently hitting his inverter limit of 6kW in January, and has generated over 1.5GWh in the last six months.
Yes, but that's double the amount of panels for E/W? I noted about 15% more for South only based on unit area of panels installed. South always wins per unit area? If you have two large E/W roofs (fortunately we do) and are able to cover them in panels, then you can win out overall, but you need more panels. I think we're possibly saying the same thing
As the poster above notes, E/W can be susceptible to low sun elevation in Dec/Jan - it just clears some big oak trees on our south border, but only just!
Regarding east/west vs south facing in winter: we had our installation done a few months ago (end of November '22) and here's the generation numbers. As you can see east/west panels only doing a quarter of the south facing ones so far. Looking forward to their contribution later in the year though as the sun gets higher.
Yes, but that's double the amount of panels for E/W? I noted about 15% more for South only based on unit area of panels installed. South always wins per unit area? If you have two large E/W roofs (fortunately we do) and are able to cover them in panels, then you can win out overall, but you need more panels. I think we're possibly saying the same thing
As the poster above notes, E/W can be susceptible to low sun elevation in Dec/Jan - it just clears some big oak trees on our south border, but only just!
earlier discussion was mentioning the relatively low cost of panels once you have the scaffolding up so it can be cost effective (although woudl you be able to access the west roof if you put scaffolding up on the east? maybe more expensive than that..
using the same energy saving calculator - my 2.5kw south roof - 2280kwh/yr. (limited by old FIT panels); new 4kw N facing estimates 2554kwh/year so a reasonable increase overall although obviusly will be poor in winter. The North numbers aren't that bad and if you have a relatively small south facing roof may be something to consider
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phil4
Member
This won't apply to everyone, but possible extra costs for going over and above the extra panels are:
- Scaffold
- Either optimisers/microinverters and their extra cost or
- An extra inverter
- All associated extra wiring, isolators, checks etc.
- Bird extra proofing if used.
Just off the top of my head mind, and as I said won't apply to everyone.
I think the point being made is that as most buildings have two faces to a roof that East/West gives more useable space than N/S. So if for some reason you could choose which way round your house was orientated then E/W would be better.Yes, but that's double the amount of panels for E/W? I noted about 15% more for South only based on unit area of panels installed. South always wins per unit area? If you have two large E/W roofs (fortunately we do) and are able to cover them in panels, then you can win out overall, but you need more panels. I think we're possibly saying the same thing
As the poster above notes, E/W can be susceptible to low sun elevation in Dec/Jan - it just clears some big oak trees on our south border, but only just!
There's also a point that having generation earlier and later in the day is more useable than having massive generation in the middle, I suspect this is only an effect for a month or so however.
It's all not really relevant as most won't choose, and if you had the choice of all three then just pick all of them.
With the reduction in battery costs I expect this is no longer an issue.
If on the Powerwall "net metering" system it seems it's all about total output without thinking if getting it at a useful time of year.
