Great analysis! You won't get such good modelling and detail from most professional installers! 16 panels on my NW facing roof was Approx £4000 with a decent installer. They like big regular shape roofs and with the prices of panels plummeting, the costs are much lower than many expect. As you've rightly pointed out, scaffold costs are a significant part of having the work done. So far, my SE facing array is performing almost exactly as expected from PVGIS. The NW array however is overperforming by almost 25% compared to what I expected. There's something to be said about the sheer surface area when it comes to cloud cover and diffused light. Today for example, the sun is completely obscured but we continue to generate a solid 4kW. I am intrigued to see what happens with the algae/lichen on that aspect of the roof. Several people have assured me that solar panels fare better than roof tiles because of their "self cleaning" coating, giving less for organic material to grab onto. Others with north facing arrays do have them cleaned once a year by their window cleaner for a very minimal cost.
Funnily enough I was just watching one of your videos when I spotted your comment. I'm impressed that you've had such good generation from your NW panels, that's very encouraging. You're soundly beating my combined 6.8kWp E/W array at the moment. I've not completely discounted the idea of using the North facing roof so perhaps I'll get in touch with my installer to see what he thinks. Cleaning the panels up there would be essentially impossible due to the tight space between us and the neighbour's house on that side so they'd be on their own once installed. I'll let you go through a full Winter first and see how you get on ;)
On one of my meandering walks around the local neighbourhood I saw a bungalow where the occupants had managed to fill their roof by using what looked like a combunation of full / half / third width panels ( which I wasn't aware existed ). It looks quite neat as the combination form a symmetrical pattern.
I recently discovered triangular panels are also a thing now too, although lower efficiencies than the rectangular variety presently. I might look into half width ones too as that might help fill some gaps.
I added 6 panels to a shallow (10º) veranda roof. They are surrounded by trees but the panels are effectively pointing at the sky rather than the direction of the sun or trees. Over the last 2 months they were my highest producing panels. But why, that makes no sense if you use the online tools? Well, we get lots of not particularly sunny days. Modern quality panels produce a good rate of power even when overcast with a relatively thin cloud layer. Over time the low peak but constantly producing panels produce more than my peak performers. On a good sunny days the shallow panels do not match the traditional best-placed panels but living in the north of England we don't get that many of them. The more you learn etc. The other thing I did miss was the relative importance of west facing panels compared to east facing. West facing produce the same power but more income due to time of day tariffs paying more for late the afternoon / early evening export rates. I missed this bit and I lost some income that was there to be had. I balanced panels on power predictions rather than income predictions. These tools can mislead the unwary.
I'm a big fan of West facing panels for exactly the reason you described. I have neighbours with great West facing roofs and I'm working on convincing them to add solar.
It's worth looking at the MCS guidelines again. They don't say that you absolutely must have a 400mm gap round the edges, as long as you take extra precautions for any additional wind shear and drainage into gutters. That said, I spotted a very cowboy-looking job in my neighbourhood where they'd gone all the way along a roof at the very bottom of it (clearly done from a ladder) and had to slightly BEND the last panel up onto the adjoining gable end to get it to fit. Yikes..!
Tim, please do not consider putting/fitting house mounted wind turbine. Having now been on a Wind Turbine course and the complexity and minimum requirements for any decent wind generation, I can say with confidence that your property and land is most certainly not suitable. Happy to share why with you directly.
I had more or less come to that same conclusion, so fear not. I keep re-evaluating it every now and then but it's always the same conclusion, that it's really not worth it.
@TimAndKatsGreenWalk I am glad, honestly. I personally have purchased 120% of my years consumption of the Whitelaw Brae project from Ripple to meet the wind generation need as I cannot have solar currently, but I do have a GivEnergy AIO for load shifting which is just awesome
Tim - visually it looks like you can get two more panels to each of the East and West arrays. Also on the south array I think you might be able to get 6 additional panels in landscape i.e. row of two at the top with one below on each side. Using a façade mounted array, I have just increased my own system to 8.7kWp
Looking at your existing panels, if you slid them closer to the sloping edge of your roof, it looks like you might be able to fit 3 more panels per side on your existing East/West layout. I queried the "400mm from the edge" with MCS prior to us getting our own panels installed. It is only a recommendation, not mandatory subject to the panels having enough support. Our installer was able to fit an extra 2 panels leaving us with something around 150mm and not 400mm from the edge. Additional mounting strength was achieved by mounting on 3 rails instead of 2 for the panels on the outside edge. We have also installed an additional 9 x 435W panels on our north facing garage back in January. We are expecting them to produce around 60% of if they were south facing. We were able to do this at relatively low cost as 1) We were able to utilise the 200% overprovisioning allowed on the SolarEdge inverters (already had 10 panels on garage south facing roof) 2) As a single storey building, no scaffolding was needed. 3) I'm able to keep them clean easily using a long handle water fed window cleaning brush from the ground. Time of year for installation is likely to help reduce the price. Most installers are quiet in December/January and were pleased to have a few days easy work.
Sadly appearances can be deceptive. There isn't quite enough extra room on the E/W sides, although that would be great if it was doable. I'm still keeping the North facing roof under consideration, so maybe one day I'll add some panels there as I think it might still be the best option as long as the install can be kept to a reasonable cost.
Can't share images via this message system, but I did a month end data grab from the SolarEdge system on our garage. For July, the north facing panels produced 80% output that the south facing achieved.
@@JimGayes that's impressive. I used PVGIS to see how the North roof could perform and in the Summer it was surprisingly good. Not so great in the Winter compared to South but the extra export in the Summer would help build up a healthy amount of credit for the rest of the year, for sure.
Another option would be to expand your north facing roof with a dormer, creating extra living space as well as a flat surface for solar panels. Adding more living space adds value and comfort to your home and some room for solar panels is an added bonus. Not the cheapest option for sure, but something I wanted to mention anyway.
Adding more battery isn't really necessary once you've covered your typical usage (for Winter, say). And if you have more generation you actually don't need as much battery anyway (well, you still need enough to get through the night as a minimum). But I agree that getting as many panels as possible is generally a good plan.
@@TimAndKatsGreenWalk Same here, speaking to National Grid at the Everything Electric North show, things should be improving in moving to 3 phase and plans are apparently in place to help reduce costs to do so.
We have 18 x 375w Sunpower panels & would like some 440w versions but It’s the faff of the scaffolding & the resale value of my existing one that puts me off
I won't be replacing any of our existing arrays any time soon. Maybe in 10 years when panels are even cheaper and higher output, but not for a good long while yet.
Haha! You know what, I've spent a good chunk of today looking more into how I could make the North roof work. You're probably right, but I think it's likely we'll wait another year or so. We shall see!
Thankfully you didn't get as far as plotting cumulative savings against cumulative cost like for your extra battery size consideration. However, considering the total system capital cost, payback time and effective return on investment as an annual percentage it would be interesting to compare all these things: Extra PV Extra battery Ripple The biggest rate of return is likely to be your existing system (I worked out mine to be 17.5% p.a. so Ripple didn't seem to cut it) but adding other items, although perhaps lowering the rate of return could increase the total return - and you have to consider where else to invest your money and is it better than a savings account etc.
You imply both that you don't want to see me do a financial calculation and that you do? I'm getting mixed messages here. Don't worry, I've got big plans for a financial video that will blow your mind. You'll love it, I'm sure.
@TimAndKatsGreenWalk I'm hesitant. It depends on the perspective you take and which calculations used. Previously with your battery discussion I suggested that the perspective of the whole system should be used to work out whether an investment is worthwhile. On that basis a bigger battery on my system return would be paid for in a couple of years - contrasted with a cost benefit of the battery in isolation which would take longer than the battery lifetime. You seemed to prefer maximising the rate of return and I suggested if it still pays for itself then it's worth it. You suggested I didn't understand your calculations - ouch! So let's not go there again 😂. But again the consideration of an extra investment and whether it's worthwhile is interesting. For extra solar PV a similar question arises. The extra PV has a high installation cost with scaffolding DNO approval etc. Naturally the cost is compared to the marginal benefit and tends to be dismissed. However if integrated into the whole system and if it pays for itself within lifetime then perhaps it becomes worthwhile? It may take longer to pay for itself but it pays more by then. Ultimately if you had an equal size spare roof you could repeat the whole thing again. Your whole system takes longer to pay for itself by the time difference of instalation but pays double by then. I have a smaller dilemma at the moment - should I add an extra £300 designer radiator into my wet system? It'll look nice and perhaps I can reduce my flow temperature from 40°C to 35°C and achieve 0.2 better SCOP? Even a marginal calculation pays for itself in two years. As a system calculation it makes little difference but at least a positive one. It's a lot of faf though. A Ripple investment pays a rate of return similar to a savings account and takes a long time to pay for itself with loss of deposit. Could the same money be better invested in increasing the size of a component part of an existing PV, battery, heat pump system? As I mentioned my system currently returns 17.5% p.a. paying back in 5.7 years, and even if increasing a component were to reduce that percentage and increased that time it would still be better than Ripple and you keep what's left. It also depends what you want to do with your savings. You might want to spend them on a holiday or landscape your garden instead. P.S. I suspect wind won't be worth doing but it's an interesting subject. I look forward to the prototype 😉
Your comment about a further Ripple investment would seem the better option, but perhaps in a wind farm rather than a solar park? The wind farm just spreads your investment into a different renewable source as a hedge against years ( or seasons) with poor solar irradiance.
Very interesting Most of my thoughts/suggestions have been covered by other people except who owns the trees causing the shade problem? Could those trees be pruned (amount by negotiation obviously) If for instance you could solve the shade issue by pruning 2 meters off the top that would be a 15 minute job by a professional with a chainsaw and a rope to climb the tree
I actually really like having the trees there so wouldn't like to see them pruned too much. They also have TPOs on them so there's not much that could be done in any case. Having said that they are Ash trees, so I expect they're somewhat living on borrowed time anyway.
Interesting to see similar thoughts in terms of Enphase for additional panels in awkward places. Had a little look at GIS for panels on the other side of the house (North East) and the figures are surprisingly good overall, nearly 2/3rds of the production of our south-west array. But it seems that all of that will be in the summer when I have plenty of solar anyway, and production is pitiful in the winter when some extra capacity would be super-useful.
Yeah, I'm thinking about this in terms of annual total, so building up credit during the Summer. I think the only reliable way to get Winter generation would be wind, but that has its own issues.
That's a shame Tim, that you can't add more solar. Like me, you are all electric and I bet you feel in the depths of winter, if only I had a bit more solar. With those south facing panels, did you try landscape orientation, as you showed them only in portrait orientation. With me, trees across the road from me shade my north panels early morning in winter and the second story of the house does the same to the shed panels until about 9:30 AM. Don't give up just yet as panels are different sizes and you may find some that might fit.
I did indeed try landscape, but sadly that didn't work either. I'll be keeping an eye on things though, as it appears there are triangular panels that might be viable at some one point (although currently they have rather low output for their size and cost).
@@TimAndKatsGreenWalk his has been an interesting one to follow. I'm awaiting DNO sign approval (40 days in so far...) and will hopefully have 10 panels East, 5 South & 5 North for an 8.6kWp. Really odd roof so the North & South panels will actually be over 4 faces as it's a double peak roof. Got the Fogstar 15.5kWh battery arriving next week so exciting I'm getting closer to having solar! Been watching too many solar channels and being envious 😉
@steve_787 nice! Sounds like an interesting system. I waited ages for mine to get installed but once it's done it feels great. And then you can start doing your own videos 😉
@@TimAndKatsGreenWalk think it'll have a bit of everything on it (except West facing panels), bi-facials with the Tigo's all round, although fork isn't getting much benefit from his but I need them to get the North/South panels on one string. I have considered doing some video's once it's up and running and my mate has done a fly over for me with his drone as a "before" just in case I feel brave enough to go on camera with my dull voice 😅
Have you thought about a couple on south gable end of house . Check out vertical flat mounted results you may be surprised at generation no scaffolding needed a cherry picker would do
Would fitting in landscape give you much more. Or go closer to roof edge which you can do. Loved the video. Panels just so cheap now, use a tower and do it DIY, cost sub £100 a panel for 455w now.
Sadly landscape wouldn't help, I tried all sorts of arrangements. The North facing roof is probably the best option, though, realistically. There's no way I'm doing this myself, especially on a slate roof.
Interesting video. North roof is your best option as you've discovered, south roof is just not really viable. I had a 4kWp system fitted in 2015, then DIY added a 4.84kWp system on my double garage. I am now adding another 6.8kWp, thats 12 panels on a WNW roof, and 3 bi-facial panels mounted directly to the WSW facing rear wall of the house, I did also want to put up a canopy but the wife vetoed that and it would also require planning permission. Those 15 panels are going to cost about £4000 as I'm doing most the work myself, I'll just use an electrician to complete the wiring and sign off for insurance purposes. The new panels will give me an extra 5300kWh a year, total will be nearly 14,000 kWh. Unless things have changed with your local electrical infrastructure you're unlikely to get an increase on your export limit, and your neighbours will likely be less due to yours, but a perfect roof for solar presuming no shading.
Very impressive, that's a heck of an upgrade to do yourself. Our neighbours have a great roof for solar and are presumably on a different phase to us, so with any luck they should be good to get a 5kW limit too, hopefully.
@@TimAndKatsGreenWalk Yes, that's a good point they may well be on a different phase. When I added solar to the garage I also installed 8kW Victron inverter which gives whole house back up with 29kWh of storage and got G99 for 11.68kW export (8kW Victron and the original 3.68 Inverter).
If you have a look at your virtual diagram there are hundreds of squares round your house can you not stick panels in each square, or rent the field at the back 👍😀😀
I’m astonished with how cheap panels are getting. £50 for a 415w panel is approaching the same cost per sq metre as concrete roof tiles and even some fence panel examples. So my idea is to start replacing the fence panels with bifacial solar panels, just because some of the fences are starting to fall apart. I’m also eyeing up the walls of my shed. Mounting adaptors are expensive, but nonetheless it illustrates the fact that when solar becomes as cheap as traditional building materials, any electricity they generate is essentially free. Need a new inverter though. Eyeing up the 6kW solis hybrid inverter and adding a Pylontech cabinet that I can build up as time and money permit.
I think you're right, eventually all roof tiles will be solar tiles as they'll be the same price, although I expect that'll take a little while yet. I like the idea of solar fences too. We don't really have any good places we could do that though, unfortunately.
@@TimAndKatsGreenWalki have some North facing panels on a similar roof. They remain pretty clean as long as there is some rain as these panels have an anti-stick coating. The power they supply is not that bad at all. In the Netherlands we have a lot of cloudy days which make these panels almost as effective as the south facing ones. It sort of makes you independent of the grid most of the day, regardless of weather conditions. Also, you do not need micro inverters for these cloudy days and just get a really simple string inverter, which can really bring down the cost of the system.
@@SolAce-nw2hf I worked out that they'd be probably worthwhile once they hit about £50 per panel (for 400W ish), so maybe one day in the not too distant future I'll revisit the idea.
@@TimAndKatsGreenWalk In the Netherlands solar panels now cost about €80 (0% VAT this year) for a 430 Wp panel. China has over produced and both the government and energy suppliers are now realising they are losing money because of the kWh credit scheme here. Unfortunately solar installers are going belly up as energy suppliers are charging extra cost for anyone who has solar panels and the new government wants to stop the solar credit scheme as of 2027. So I will be getting even more solar panels before then so I can charge a home battery all year long and tell the energy suppliers and the new government to put those plans for the two Nuclear power plants where no one can see them 😂
@@TimAndKatsGreenWalk Panels are already stupidly cheap now - but we need to wait for the cost of installation to come down now. All the quotes I had (this year) were over £500 per panel. I think the sudden rise in the cost of electricity a couple of years ago caused a big rise in demand, and installers can't grow fast enough. In a couple more years it should even out again.
Interesting video. I presume 3 per roof wouldn’t fit in landscape mode either? I have a west only array and often look at my east roof (with lots of velux windows and a chimney) wondering if it would have been worth the hassle and expense of squeezing some panels on there.
Although not common, they are available although I'm not sure they would make it any more viable for Tim with the space he has, especially as they are more expensive than more standard, rectangular panels.
Couldn't you get 6 panels on those triangles by mounting them at the same angle as the hypotenuse? No one said they have to be at 90 deg? I can't really tell without exact dimensions. Alternativel you could use half panels to fill the roof more effectively.
Possibly, although I think mounting them diagonally would be tricky. I did discover triangular panels are a thing although they are expensive and low power compared to rectangular ones, so probably not worth it.
Should of bought the neiogbours house 18 panels south facing, you coud powered the whole street !!!!!!! Like you surprised you can't get 6 panels on the roof, how about buying some slightly smaller panels to be able to fit 6 panels? Like you in the future I would like to fit more panels I have a dormer roof facing East & South I just need some more power for the winter to help power the the air to air heating system I want to fit in the future, Along with an extra battery storage my heating costs on peak rate would only happen I think 2 to 3 months of the year. I would like to think that with the extra generation and battery storage there would be enough power to help keep me off peak electric for 5 of the 7 months we heat our homes..
We were actually aiming to buy that house next door but sadly it had already sold and ours was the only one left. But as it happens I don't regret it and the E/W array has worked really well for us. I did look into smaller panels but they are few and far between, and actually I couldn't really fit much more on, in terms of total wattage. I'll keep an eye on things and potentially the panels will become cheaper and more powerful, at which point it might be worth revisiting. We had very little peak draw over Winter (see my extra battery video) and I reckon we could reduce that further next Winter with a change of strategy. I hope you're able to achieve your aims too.
@@TimAndKatsGreenWalk Yes, I am thinking of doing so myself. With prices for solar very low a garden fence is almost more expensive per square meter. The other option I am considering is building a semi transparant solar roof next to the garden shed with double sided solar panels, although getting that water tight would be a challenge.
Would adding a solar fence mean creating another string input to the inverter? I’d like to add a solar fence but My GivEnergy inverter can only take 2 inputs and I have east and west panels
@@iancollyer9995 yes, you'd probably need an extra inverter for any new strings. Or you could use micro-inverters on the new panels which would then go straight into your AC supply.
Are ground mounted, south facing panels in the back garden an option? Super cheap to install, but again you would have to be mindful of the shade from house and trees.
Are your neighbours on their own supply or a looped supply? My dads is on a loop and both has solar. It increases voltage over 250v and trips the car charger during the day. Not an issue now as on a overnight tarrif but something to consider if the tarrifs change at some point
Hi Tim, did you consider putting 550w or the new duel sided panels on the 4 x south facing? If you can only have 4 get the heist wattage panel that fit. Then do the math again.
@@serraios1989 That does make sense. I've read the main benefit when combined with certain micro inverters are that they start and keep performing in low light, much earlier than traditional panels. Not convinced with the additional expenses if it'd be worth it though. If Heatable ever provide the data and it looks good enough, they'd be on a mostly North facing roof. That is assuming any new panels + micro inverters would integrate with my existing Givenergy inverter. 7 panels on 1 string, and 8 on another. So slots maxed out.
@@stuartburns8657 Heatable are not trustworthy. They still say in their videos that without microinverters, if one panel is shaded the whole array is underperforming. That’s a lie. The panels have bypass diodes and the partial shading doesn’t bring down the rest of the panels
More panels? Here in Lincolnshire in 2024 it's been like a nuclear winter compared to '23. Not ran the numbers yet, but I think we're 25% generation (and thus export) than the previous year. Truly dreadful. I had a G99 DNO and had 15 x 395 panels. Not certain if I'd need to reapply or update. Either or, with weather like this and rates sinking, I've put on hold any futher PV or battery expansions
@@TimAndKatsGreenWalk Glad to hear somebody's doing ok 👍 To put it into context, '23 moved back to Flux 2nd week of March. '24, back to flux 2nd week of April, and felt obliged to topup the battery 4 times. Normally its grid only until late October 😢
Bedfordshire, so not that far South of you; Jan-May 23 4048kWh generation, Jan-May 24 4037kWh. April and May this year are about 15% down on last year, but March was much sunnier
@@geoffreycoan Interesting thanks. I'll crunch the numbers properly tomorrow, maybe I'm being overly pessimistic when I said 25%, but I don't expect to be too far out
@@geoffreycoan So I'm 15.7% down from 1st Jan '23 to 31st May vs '24's equivalent. But 1st March to 31st May between years is only 6.5% difference. Blow me down with a feather
Still waiting for our mixergy iHP, paid deposit 3 months ago, keep pushing the date back, have you got yours yet???? We were promised it in late March....
