When we used to go to the beach in a very sunny climate, we would build a shelter for our infant son with four sticks, a blanket and some string for guy wires. This worked fine as there was hard shade under the shelter. Then one unusual hazy day we did the same. The poor little bloke was sun burned. On a hazy day, significant radiation comes from all points of the compass. Same thing with panels facing away from the sun. On all hazy days, they are generating a pretty significant amount of power.
Gary, you are mistakenly attributing the yield from the north facing array as being from ambient light…this is not true. The yield from the north facing array during the summer months is due to the azimuth of the sun in those months…the sun rises in north-northeast and sets in the north-northwest. A south-facing array will only get direct sunlight on it when the sun’s azimuth is beyond east, and stops after it passes west. So having north-facing panels will produce useful yield between the spring and autumn equinoxes as it captures the northerly element of the sun’s azimuth during those months. Hope this makes sense?
My install was April 2023 and I worked with the installation company on the design. At that point they were talking about what was needed for the average house so I had to push to max out on panels and battery. I wanted some vertical panels on the rear of the house (SSE side) and some on the north facing roof at the front of the house. They didn't do vertical mounts and didn't want to do north facing. I talked about ambient light (in the NW of England it's mostly cloudy) and we do get some direct sunshine leading up to sunset. He explained that sun strength was like standing in a flowing river; side on you don't receive much power so there was little to no value in north-facing panels. I deferred to his knowledge and experience so feel I've missed out on better generation.
Your points about "indirect" or "ambient" light (diffuse irradiance) are well made. Also, in the UK in the summer, the sun rises in the North East and sets in the North West, so there is the opportunity for some direct irradiance on a north facing array in the morning and evening. This effect is exaggerated the further north one is located. Furthermore, at noon there can be some direct irradiance on a north facing array if the sun is at a higher angle than the array pitch i.e. in summer. This effect is exaggerated the further south one is located. I have been mulling the advantage of adding an array to the north facing roof of my house (I already have arrays on the south of the house and east and west on a detached garage). At the moment I am hesitating because the north is the street facing side and would affect the look of my house
In 2011, we built a solar system with 560 kWp in Germany with orientations in all four sky directions, south, north, east and west at a roof pitch of 15°, which we still operate today. The northern roofs have an annual yield of around 800 kWh/kWp, the southern roofs 1000 kWh/kWp. Even today I ask myself why it takes so long for the obvious to be implemented?
Hi Gary. Now argument about panels facing away from the sun. But the problem now is the cost of battery storage. As we all have seen, batteries are now below $100 per kWh storage capacity and yet a contractor quoted me a price for a Tesla 13.5kWh power wall 19 times this price. Something is wrong in the supply chain.
We have (to within about 5°) a N/S double garage, set back slightly on the W side of our house. So the S roof is subject to shading from the house up until around midday day. Initially we filled the S facing roof connected via a SolarEdge 4 kW inverter in conjunction with SE optimisers for the shading. In February we took the plunge (because of the low panel prices and no scaffolding required) to get an additional 4 kWp of panels added to the N facing roof. This add on was relatively inexpensive because we also took advantage of the 100% over provisioning capacity of the original SE inverter, so we have the S roof connected on one string & the N roof connected to the 2nd string input. We also had optimisers fitted to the N panels. Our experience so far that to date the N roof has produced around 62% that the S has. (1.97 MWh N Vs 3.18 MWh S) This figure is higher because of the shading the S roof experiences. During the long grey gloomy days we've been experiencing the last few months, although still quite minimal, the N roof produces almost identical to the S roof. During the peak summer months the N roof produces more first thing in the early morning and late afternoon/early evening because the sun does actually rise and fall for a few months to the rear of the house. From the positive results from our garage roof experiment, we are currently talking to our installer about doing similar on our N facing house roof. More costs to weigh up doing this one as the house Solis inverter can only be over provided by 50%, not 100% like the garage SE and we will need scaffolding to achieve it. But we do have the potential to add an additional 14 panels. Decisions decisions!
Upsidedownfork is an excellent and cadid channel that is straight down the line. I am looking to copy a SSW-NNE roof setup with the majority of the pannels on the rear due to the config of my home! Time will tell once its up if it will pay for itself or not. Great video and something everyone should consider of fitting panels!
true. I've got 2 panels (1.1 kW array) on a north-facing roof, just for the test. and compared to my other 50 kW of mainly south-facing arrays it produces nothing, but... in a summer month - 90-100 kWh out of these two panels only made me really scratch my head... and, in the fog, rain, snow conditions - they produce roughly the same amount (per panel, or per 1 kW of array), not much difference. well, and still, the only reason to put your panels north - is only if you have filled in every other possible roof (or ground based construction) angle. I'd still vote for a vertical south orientation on the house facade, but that makes it look a bit awkward...
I have a secondary solar array of 6 panels in the midlands with no shading. 3 pointing NNE and the other three SSW. It is an Enphase array so I can see each panel. Since 1st January 2024 the north facing have generated 698Kwh and the south facing 935Kwh. So north facing 78% of south facing. Definitely worth having.
You still have to consider the individual characteristics of each installation . As well as the pitch of the roof, the individual shading at the ends of the day . A steeper pitch will generate less at midday even in summer , a flatter pitch will get much closer to the south array. But a steeper pitch will do better at the ands of the day when the sun is lower but then shading is more likely to be an issue. In Oval Renewable's example the pitch is relatively flat , but also the front roof is shaded by neighbours at the ends of the day whereas the rear north facing roof which is not shaded will pick up early in the morning and hold later in the evening in the middle months of the year. In this particular case that will compound the advantage of the north array. It's pretty much the ideal case for a north facing array .
With the prices dropping, it’s getting to the point it is cheaper to build fence panels out of bifacials instead of wood, so basically from an install perspective if you don’t mind the asthetics, put a panel there… please though, solar roadways will NEVER be viable 😂
Bottom line is to put as many panels up as you can afford, maximise the cost of having the scaffolding up and the installation work, regardless of the orientation. In fact diverse orientations will extend your solar generation day compared to having just panels on say the South roof
On the one hand I wish I had known about this 18 months ago when we got our solar installed. In the early morning and late evening our North facing roof receives plenty of sun. On the other had our inverter shuts down dozens of times a day in peak summer because of over voltage protection because the infrastructure in the street can't handle the amount of energy generated at those times. So in that regard we already have plenty of solar. What we really need is an affordable battery and properly integrated software to coordinate generation/consumption between the solar, the heat pump, the EV charger, home automation system and potentially battery. Unfortunately I've been very disappointed by that. Officially all of the products we got are supported but it's still not working together correctly. And getting support from the vendors has been gruesome. I live in Belgium, so rules/legislation and available companies are somewhat different here.
This is very interesting. I have no usable east, west, or south roof space and have taken to putting the panels on my shed. But this suffers a lot of shading issues due to very high trees in the neighbour's garden to the east and opposite the property to the west and being relatively low down. All the same, these modern panels and the use of microinverters means I do get usable generation, but having watched this video, I'm very tempted to put a second array on my north facing roof.
I've got a matched north/south ish array on a shed. Shallow pitch: 22.5 degrees. North manages something like 68% of South over a year. The really interesting thing to me is that on an overcast flat light day i.e. a day when you are struggling for power they generate almost exactly the same energy over the day.
I live inPhoenix Arizona and my northern facing array generates about the same power during summer as my southern one, because the sun is almost directly overhead. There is quite a bit of drop-off in winter on the northern array, but I don't care since my AC isn't running I generate way more than enough power.
The UK doesn't get direct sunlight anyway so it doesn't matter how you set up your panels as long as it is outside All fun aside: I am considering a North array too and I am curious how much that would benefit me, especially in winter where there is no direct sunlight. I have excess solar power already in the summer and I'm in no need for more during that time
Spot on Gary. I plastered my entire pure N facing roof with 12 panels a few years ago. Here in Dublin, the return is 55% of pure S facing, so very close to the percentage you got. I got the panels for free as the frames were dented and I did the install DIY with the help of a roofer. They have already paid for themselves and will continue to contribute. I live in a small semi-detached house but with my 44 panels and 80kWh battery and two EVs, I am already energy emissions neutral (I generate 14MWh per year)
14MWH per year for a small semi does not make sense. Here in S England I have 4kw on the roof of my medium sized detached house. I get 4.3MWHvper year. There is space for another 1KW so the potential is for about 5MWh but, even if I put panels on the north facing side the output would be nothing like 14 MWh per annum.
We have a 10.6kwp east west south setup with 36 panels and yield 9.8mwh a year average. Our south array of 16 panels yields 3.9mwh so double the panels you get at least 8mwh, add the 12 north face panels at say 3mwh you can get to 11mwh. It comes down to pitch and local factors so ends up near enough 14mwh.
@@rogerphelps9939it would make sense when you’re running multiple cars from it and full heating. We consume about 3000kWh for our heating & HW alone through an ASHP, and about another 3000kWh on top for my EV.
@@rogerphelps9939 I have 44 full size panels, 10 on my S facing roofs, 12 on my N facing roofs, 14 on my large shed (the width of the property) and 8 on a wall. 16kwp total, generating 14MWh per year. Enough to make my house energy neutral
Apart from the matters mentioned below, another one may be the reduced efficiency of panels that happens as the surface temperature rises. I’m familiar with this, with a group of SSW panels. On hot days around mid Summer, they are a lot less efficient than a typical Spring day with sunshine and showers, and are well within the capacity of the inverter. So, the south facing ones are probably affected by this feature compared with the north facing ones, which may well be cooler much of the time.
I had a similar discussion with my installer over whether it was worthwhile to put a relatively small number of panels on the east and west facing parts of my hipped roof . For me it was a no brainer as I'm limited in number of panels on the south roof by the hipped design and the east/west roofs aren't at all shaded for 80% of the year. Installers concern was disproportionate increase in install costs vs. the number of panels , which is true, but has def. been worth it.
Where you are on earth makes a big difference. I am currently at 12 degrees north from the equator. My roof is facing south-east. This video is very interesting for me because in winter the sun is in the south and in 'summer' for a few months it is in the north. My roof is only at about 10 degrees angle. I am confident now, that I will get enough sun year-round.
Why not do a reverse raise to make the north array face south? We do that here in California. It looks like you’d only need one row of panels as you’d get about double the output, which might be less money overall as racking is less money than panels.
In the UK, there are building regulations that don't allow for panels to be above the ridge line of the building roof (unless approved by planning permission) You'd probably get away with making a structure to mount the panels horizontal at just below the ridge tile level.
Excellent news. I would consider a video on the performance of different manufacturer’s panels in the same location in dull weather so the panel manufacturer choice for the north slope in ambient light might be different to the south slope panels?
That was a great video - most of us in the UK have small roofs so makes sense to fill it up. Even if you only get half the generation, thats still adding a third to your overall home’s generation which can have value if you have good export options and helping to cover baseload usage in dull/winter days
My stats over the last 12 months (Southampton): SE 1.17 kWh/day/panel average. SW 1.03 kWh/d/p av = 88% of SE. NW 0.72 kWh/d/p av = 61% of SE. On overcast days (when you really want max solar) all panels produce the same amount of energy from the diffuse sunlight. Also, if exporting on Flux then the NW are generating when the value of electricity is at a maximum in the evening, so I would estimate that my NW panels have produced maybe 70-75% of the value compared to the SE facing panels. I have 17SE, 2SW and 12NW x 420 Watt panels. I probably could have squeezed on another x8 on the NW roof and slightly regret not doing so.
I have 1 panel opperating as a tester on an ecoflow microinverter, 440w JA Solar bi facial and today I managed a total of 59wh of generation over the 4 hours I managed to get enough generation for the inverter to spit anything out today. This is mostly south facing and it has been pretty overcast with the odd patch of sun. Does this seem right to you? I was expecting more from it, not massive amounts but on a few days it generated literally nothing. If you don't mind me asking, does this lign up with your experiences?
Today (20/12/24) my SE panels generated about 340Wh and my NW panels about 170Wh. Difficult to say whether yours are delivering as expected as you need to review their performance over a longer period 🤷♂️. Also it’s difficult to compare performance between yours and mine unless you live in the same region of the country.
@@Steve-6536 Yes, I'm in the north west and it has been really overcast since install but I did expect better from defuse light. It's only been installed a few weeks and it could be a few months before I have a better understanding of performance but I'm yet to hit 1kwh of total generation over those 2 weeks, which just seems a little off.
They should probably develop north facing panels with prism lenses to bend light from the south, so it’s perpendicular to the panels, especially for spring and autumn months.
That won't work. When the array is tilted away from tthe optimum orienttattion it intercepts less solar energy over itts surface and no amount of lenses will help. We get less solar energy per square metre of ground area in winter for exacttly the same reason.
@rogerphelps9939 Possibly true, I get that the potential solar surface area at a steep angle will be greatly reduced, but isn’t there also the danger that the little light there is, could just bounce off the glass and not reach the silicon ? Surely bending the light down onto the receptive surface would improve things a little, compared to just skimming along the surface ? Id be interested to see if adding a diffuser to a northern facing panel, when sunlight is only just hitting it, would improve things.
Our roof is located in an area with a lot of cloudiness in the transition period between October and March. In diffuse light, my 16 panels on the north side produce just as much as those on the south side. And in summer the sun rises at 45° East. This means I have electricity earlier in the summer. I like my occupied north roof.
Hi Gary. Yip, it’s in the data books. True north against south at 35 degree pitch equals 55% of year round generation. North facing panels should never be overlooked. At home I utilise north facing panels and panels on a flat roof, summer generation ( no export limitation) pays for all electrical usage, heating and 9000 ev miles. Yeah we have a lot of battery storage and a good import tariff. Your point is good, north facing panels work 😊
I have installed 6.3kWp on our south roof, and 6.3kWp on our North roof, 12 panels on each, and a roof pitch of 23 degrees, the last 31 days the south has generated 105kWh with max power of 3831W, and the North has generated 54.66kWh with max power of 1366W, so this confirms the findings, basically the North generates approx 50% of what the South roof generates give or take. I am however expecting the North to generate a better % when we get to the Spring and summer as the sun will be higher in the sky, and as we have a low pitch on the roof, should get more sun hitting those panels than a house with a 45 degree pitch, system has only been on for a couple of months though hence not much data. Battery is a game changer, we have 32kWh battery which will store any excess production the panels produce in the summer
Mine produce the same. Oh wait, I have 4kWp south and 6kWp north lol. Joke apart, it is reassuring that when looking at the data and trusting science we know what to expect. If only the sales people were more educated. The number of sales guys who tried to convince me not to install anything on my north roof. unbelievable.
Microinverters vs solar optimizers vs stringing the array directly into a string inverter is a different issue than this video is addressing. This video addresses direct vs diffuse radiation. In northern hemisphere, you’ll get more direct vs diffuse radiation, and direct produces significantly more kW than diffuse. The type of equipment setup you choose depends on other factors than azimuth, most prominently “shading”. If no shade, just go direct into a string inverter. Save money on equipment purchase and fewer points of failure breakdown. Monitor the array product as a whole via the inverter monitoring software. But if your array is affected by shading, think about micro or optimizers, which allow each module to max out kW on its own merits - otherwise all modules within the entire array will sink to the lowest common denominator (aka, the most heavily shaded module).
Tech has come a long way in the last 12 years or so. Installing north and south facing panels with a single MPPT would have killed your production. Now, you can have as many aspects as you have MPPT inputs without needing optimisers. Just 2 years ago I paid as much for an optimiser on each of my panels as a 400w panel costs today! Breaks my heart
Yeah, it’s one of the downsides of newer technology-whatever you bought two years is out of date already! But I’d rather have it that way than nothing changing at all 👍🏻
Pretty much the same results I'm getting. I have East, South and North panels over 5 roof faces totalling 8kWp. Went live on 28th June and have so far hit 2912kWh. This is with 4 of the panels are in a North/South valley (2 panels on each face) and even with the additional shading they are still working well. I'd say the rule of thumb should be to just fill roof to the extent of you budget, starting with the most optimal faces first.
I also did exactly the same - just cover every inch of roof space with as many solar panels as possible even on apparently disadvantageous north-facing roof.
Our roof faces north and south. Had a guest who is an electrical engineer and installer tell us to install on both the north and south sides. We are in a hot part of the world and have a lot of visitors in summer. We heat in winter mostly with a wood stove, and run the heat pump cooling for much of the three summer months. And just having the panels on the roof will cool our house by 5 degrees. Just installing the panels and not hooking them up would probably be a fifteen year payoff!
Painting your roof white has a 1 year pay-back. I am so close to the equator that the sun is in the north in summer. Even if the sun is not in the north in summer, it's going to pretty much straight overhead mid-day, meaning it doesn't really matter what side the panels are on at that time of day in summer.
I think these northfacing panels don't attribute positive if you also do have south or/and east facing panels. Because they only ad up to the surplus of summer over-production.. In the first graphs it's shown that the northpanels do the worst in wintertime.. compared to the southpanels. I think because the wintersun is too low to get over the top of the roof.. And is coming up south-east and going down south-west. So the sun is not getting "around the corner" ! It would be better to supplement east or west panels to a southfacing installation (if possible). Or wall atached south-facing 90 degreees up panels. So you will catch more of the low angeld wintersun.. So you will add up more to winterproduction..
The placement of solar panels depends heavily on your specific circumstances. Ideally, a south-facing roof with no obstructions, such as trees, is optimal. However, even on overcast days, the orientation of the panels matters less as long as they remain unshaded. Interestingly, some users have reported achieving over 10% efficiency in winter with north-facing panels, highlighting the value of real-world data over theoretical assumptions. Additionally, the performance of your solar panels can vary, as some models are designed to perform better in low-light conditions than others.
@@GaryDoesSolar I will question that. It,s more a choice if other options are done. And when the angle of the roof is not to steep. I heard of a case where people didn't,t want panels to be seen from the street.. and the put them on the back of the house for that reason north.
I guess buildings have to be built with their orientation to fit with the design plan, but I’m hoping that my video shows that we’re at the point now, where it doesn’t matter which way new builds face now-just cover them with panels and stick a heat pump in and the owners will have low/zero energy bills.
This is an interesting point and I was thinking of adding panels to my NE facing roof as I already have the SE facing roof full. Only thing is I recently installed a battery system that can provide all my daily electrical needs from half price night time electricity so the majority of generation would be exported at only 10p. As I'm paying 14p for the night electricity the difference is only 4p. Maybe a little more if I count inverter losses but I'm not sure that the maths would add up to adding more panels.
Im only using on average 8kW a day, thats inder 3000kW a year. He is generating over twice thr juice to rim my house. We are fare form energey efficient either. 7 of us in thr house, 2 dogs and a tortoise. Many devices, tv, consoles, laptops electric shower, hob, oven etc... Im assuming this house has an ev?
@GaryDoesSolar she live in one of my kitchen 1000mm double under counter cupboards, I've rooted out doors to match my kitchen doors and install one way privacy glass so we can seeing but she not out. They get very excited if they can see out. Any how is a beautiful enclosure, she wonder the house in the day but makes her way back when tired, she had a door, or rather long ramp with sand paper on it for grip, for her entrance that rinds under the kitchen unit, and exits at the base board of the unit. Long story short cos the house is at a constant 17-18 degrees, and she had the oven another 1000mm (double unit size) away, her enclosure is easily to keen at a steady temp via a 20w reptile heat bulb. The bulb is on a timer and a relay it comes on for 14 hours a day, I have a smart thermometer that opens vents if it starts to get too warm. We basically keep her in summer condition all year round, this way she never goes into hibernation mode. To many complications can come of that. She is about 22 now, so will a round pup. She will walk up you to sit on your knee while watching TV, and she will change the dogs away if the want a snuggle. We got the dogs used to the tortoise from day one. The two dogs are now 11, so they are all old couples now 😢 if only the lasted as long as tortoise do. My average overall energy is 8kw a day. I just asked ai how much does that build cost me, and it reckons it's 7 pence a day to run. I thought it would be much more. If I change her time to incorporate the 6h of 7p per kW, I could get that cost down to 4.8p per day Or if I could store the 7p per kW in a battery and use that back through the day it would go down to 1.8 pence per day. Also for the majority of the year it cost nothing to feed her, greens out the garden and veg dealings, we only really buy the calcium and vitamin powder as she never took to scuttle bones (I think that's their name). So she doesn't really coast is anything, £25 in electric and about £3 in vitamins. And a base unit for a super sick house. My wife thought I was mad, but it works great
Why over complicate ? Roughly speaking north facing panels yield 60% of energy yield of identical array facing south. East or West facing arrays yield about 80% of an identical array facing south. One can easily work the energy yield in these situations quite easily using PVGIS or similar websites.
> Roughly speaking north facing panels yield 60% of energy yield of identical array facing south. Depends on the pitch. Gentle pitch = more, steep pitch = less. PVGIS will show you this.
@@WyndStryke Not just the pitch, but also how far north you are. I am close to the equator and the sun is in the north in summer and in the south in winter. Straight north vs straight south gives me 1227.08 vs. 1322.22 kWh/year/kWp that's 93%, but the main difference is that the north facing panels give me only 68.3 kWh in december as worst month, vs. 96.52 kWh in januari as worst month with south facing panels.
@@kevinholland6841 Just because panels on a North-facing roof will always catch light, doesn't mean they've always made sense. I argue in my video they only make sense today because the lower prices and increased efficiency.
@@GaryDoesSolar I disagree with your reasoning as to 'why'. They may not make financial sense to some people, but for those looking to maximise generation and carbon reduction they have always made sense.
This is a fascinating topic. I had assumed any basically North facing roof would be hopeless for Solar PV. This shows that assumptions need questioning with real evidence ... If we get much warmer summer temperatures, no doubt that North facing rooves may be useful interns of operating air conditioning, which is still relatively unusual in UK. Best wishes from George
If your home only has SE panels now it may be a great solution for kitchen power usage. In summer my SW array can handle a lot, but a friend of mine has SE panels as well and that is basically useless at dinner time.
@@justinjoanknecht3475 I have also added NE panels. It makes sense for me as it helps cover more of the yearly usage and in the Netherlands I get the energy tax back for anything sent back to the grid. This arrangement is unfortunately coming to an end in 2027, but by then the array will have paid for itself for a large part, and will continue to support the SW roof on cloudy days for decades to come.
I am in the process of investigating in a whole roof install, and my house roof is multi faceted including a large North facing aspect. I plan to have a large array on this facet and 5 smaller arrays on the other facets. I will let you know the detailed generation information when I have it. I have based the decision to include an array on the North face based on the videos you refer to in your video, and as a patreon subscriber I will shortly feed the planned install data into your program for review. Thanks again for the excellent content.
🙏 Thanks for your analysis Gary and on this subject I have a few things that I would like to say. Unfortunately, I cannot compare my system with any of the ones you have discussed for one reason but I'll come to that in a minute. The first thing that strikes me though is that all of these installations are based on conventional domestic inverters normally only featuring one internal MPPT which has to deal with two different orientations (please correct me if wrong) We know that this is not the optimal solution as the MPPT has to combine the two sources and average them out so, in your example, the south facing modules would produce marginally more if they were handled by their own MPPT and that obviously applies also to the north facing ones too. Back to the first reason why I cannot compare my system to any of these which is due to the fact that they are all grid-tied as opposed to mine which is totally independent, at least for the moment. But just to let you in the picture, I have installed 15 modules on a ground mount, fully adjustable from a summer 28° to a winter 72° in order to potentially maximise the generation and an extra 5 fitted on the roof of my solar shed at a mere 15º. This also allowed me to confirm what you have just said and, namely the fact in this country the Sun is not always shining as much as it would in Italy where I come from, as a result of which, especially in the winter, they seem to produce more at an average angle, somewhere between 30º and 45°. The production from the 415W x 20 panels doesn't get anywhere near the figures that you mentioned even though I have two independent and expensive MPPTs, one for each orientation. Since my system does not export and therefore cannot maximise the usage of the Sun, particularly during the summertime when there is an abundance of it, my 20 kWh batteries are constantly between 80 and 100% throughout the good season and this is probably reflected in the much lower annual readings obtained (around 4500 during the first 11 months), basically use it or loose it. Unfortunately, I have not yet been able to remove some sheds that obstruct the sunlight in some parts of the year so that also accounts for some of the losses. I’d like to share with you a brief video (unlisted) of my setup which I have constructed myself even though I am practically new to the game and you will soon realise the cost of it is somewhere between 2.5 and 3 times as much as some others like the one in the UpsideDownFork video, far too much due to my age (72) but I did it mainly as a learning experiment. Once again thanks for all your videos which I have been following with interest for some time now. ua-cam.com/video/lExITYwRQOc/v-deo.html PS) Please forgive my accent in the video.
@@UpsideDownFork I had a feeling that was the case and I was expecting some corrections to my message, I'm glad to hear that especially on the cost front, I imagine that one of those inverters wouldn't cost much more than one of my MPPTs. Things are changing rapidly !
I also just noticed about the generation in the winter, you say its only about 10% of the generation of the South, well my generation over the last 30 days has been about 50% of the South, so I think that calculation may be under calculation for the winter months, My panels are not exactly N and S, the South are slightly tilted towards the West, and the North to the East, so that may be the reason why, but I dont think so.
Unsure if this has been considered but we find that the north facing side of our roof generates a thick moss covering which the South facing side does not, spoke to our solar provider (who installed out south facing panels and with whom I am discussing regarding adding north facing panels) and he advised the north facing panels would need to be cleaned once a year
Once a year seems a little extreme. Whilst hanging Christmas lights, I've been up on a ladder to inspect the NW and SE panels on my house. After 1 year they are absolutely identical. No build up yet. I'll get back to you in 5 years time!
@ it would depend if there is trees nearby too it’s not that straightforward I had new panels put up this year March north facing they built up a film in few months. They are only facing first winter now.
@@sweetvuvuzela4634 oh wow! We are surrounded by trees on that side but they aren't too close or too tall. I am planning to get myself a 30M water fed pole so I don't have to pay the window cleaners to take care of the solar panels for me. 👍
My west/north panels to well. The biggest problem is the suns height. Even when the sun is good it is too low to hit the west panels well and in mid to late afternoon it is too low to get above the other houses. I look forward to the clocks changing each spring/
I think the biggest factor in a north facing array is the pitch of the roof. If it is a gentle pitch (under 30 degrees), then the north array will get some direct light in spring and autumn, and lots in summer, not just ambient light. I have an east/west roof myself, 23 degree pitch. If it was north/south, then the north array would be effective most of the year. If the pitch of the roof is strong (say over 40 degrees) then the only direct light will be in summer, and the overall generation would be far less. Try modelling a northerly roof in PVGIS with a very gentle pitch versus a very strong pitch, and you'll see the difference.
I have been following the two UA-camrs you mentioned also my neighbour has a north facing array. I am now convinced enough to put them on my north facing roof next year. I have a south facing array installed in 2011. With advances in technology etc over that time I predict the north will produce as much solar as the south lets see 😀
Wow, 2011. Are you replacing those panels at the same time? One of my neighbours also has some blue panels on his SW roof, but installed about 7 years ago if I remember correctly. Replacing those panels with modern ones should add nearly as much yearly production as adding new panels to the NE roof. Another option is moving the older panels to the north facing roof, but I am not sure that is worth doing.
@ Thanks Gary you and your fellow UA-camrs have given me the confidence and knowledge to go all electric with solar battery storage and air to air heating plus Mixergy water tank. Apart from UA-cam advice has been difficult to find.😀
Definitely have panels all round..... I have 4 panels ~25' (NNE); 3 panels ~115' (ESE); 4 panels ~205' (SSW). (30' pitch, Region 7E) 4.83kWp I've only had these since early October, but can already see that the decision to include the north has been the right one. Yes, as we approach the solstice you'd think you wouldn't bother with any of them, however I've seen some surprising days. On average, so far, I've seen the NNE generate about 20-30% of what the SSW produce. My ESE is fairly masked by the (close) house next door, but they do come alive again a bit later on. With the sun now so low, even my best panels are poor as they are masked by houses on the next street. I've been taking daily LUX measurements at about the same 'start of day' time to help reviewing my generation log. So far, my bigger 'winter season wins have been from battery charging in the cheap rate period, and deferred washer runs to that time. My costs are about 60% of normal due to all of this. I've not yet really decided on tariff as it's all new to me, so I started on Flux for a start. (I have a PHEV, but neither it nor the charger match the Go tariff). My feeling on battery size is that I'd aim for about twice your average daily usage for battery capacity. So for me, I'd want 2x10kWh. I have a PW3 (at 13.5kWh) and will be adding one expansion pack when they become available next year ~ Tesla say they are due Q1-2025 in the UK. Thank you, and all the other UA-cam channels for your combined advice.
Probably worth looking at the Cosy tariff if you’re eligible as it’s unlikely you’ll be exporting any excess solar during the winter months. Cosy gives 3 sessions at about 12.5p/kWh so you can keep refilling your battery. Works really well if you have a heat pump(s) but might also suit your PHEV too 🤷♂️.
You need to compare generation for an average summer day between the N and S facing panels. That will show why the N ones contribute more in summer (early morning and late afternoon). This may be useful for some people but if you are already generating more than enough from your S facing array, then you will be sending it back to the grid (or batteries) and then the economics depends on your tariff. In the winter the extra generation is much less but may be of interest if your S array is limited.
Recently seen a video about Solaflect EV Charging. Their unit is mounted on a pole using stay wires to transfer most of weight to pole allowing for lighter frame. It follows the sun. If we could place units like this on new housing, it would not add weight to roof, pole could be in center of house allowing for short runs from batteries saving on cabling costs. Bifacial panels and a white roof would increase performance.
@GaryDoesSolar I'm imagining that vertical bifacial panels would be mounted on the ground, the flexing on a larger panel would be substantial. Roof mounting will give a large measure of protection from the wind. I did see in the recent storm that a large solar farm did suffer damage. How did domestic installations cope?
@@ianbigsand7 Ah yes, apologies - I misunderstood... You've got me thinking about my own garden fences-there is typically always some kind of damage after a storm...
One more reason why north facing panels yield relatively more energy in the summer compared to to the South facing is due to South facing panels heat up much more than North facing panels - so there is a loss due to temperature that occurs on southern angels which northern ones wouldn’t incur (or incur much less of it)
I have almost exactly what you are looking for. I have a 3.2kw South facing array and a 4KW North array: I would be happy to share the real world data with you.
Interesting video. Next, it would be insightful to explore the performance of panels installed on walls facing west or east. Many still overlook fundamental principles of physics in such discussions. The critical question remains: what is the cost versus return if these panels are considered purely as a financial investment?
@GaryDoesSolar as you may remember, I have 3kWp on my wall facing West. Unfortunately the last few weeks it has been only thick clouds after thick clouds... I'll send you my 12 months data if you are interested
I think OK but remember you get a lot extra in summer when you dont really need it and not a lot in winter when you do need it so I think it's good for some but not all.
There is another greatly missed calculation that needs to come into this and that is your Latitude, I am in the southern hemisphere in Australia and at about 33 degrees, I have just gone off grid, but for 14 years was grid connected and had arrays that were east, north and west, between the north and the other two arrays, the north was only 10% more output
Brain exercise. If my home is at the north pole, which produces more annual energy, north or south array? If my home is at the equator, which produces more annual energy, north or south array? If my home is at 45 degrees do entire roof?
That's not quite right. Given a fixed budget to cover only one side then S facing panels is the obvious choice. If you have a budget to fill your entire roof N and S then you will get a bit more generation. Whether it is economic to do so is another question. Nobody would put panels on the N side and leave the south side empty.
Go back and watch the video. No one is suggesting you only put Solar panels on your north side roof only. He is saying if you can afford the additional cost which may not be that much more. Then it may be beneficial to have them on both sides
I've started looking at this myself for my garage roof after watching UpsideDownFork. And I agree... I think it's worth doing though I would like more data on the summer/winter differences. His data was whole-year, but that will skew towards summertime operation.
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When we used to go to the beach in a very sunny climate, we would build a shelter for our infant son with four sticks, a blanket and some string for guy wires. This worked fine as there was hard shade under the shelter. Then one unusual hazy day we did the same. The poor little bloke was sun burned. On a hazy day, significant radiation comes from all points of the compass. Same thing with panels facing away from the sun. On all hazy days, they are generating a pretty significant amount of power.
Gary, you are mistakenly attributing the yield from the north facing array as being from ambient light…this is not true. The yield from the north facing array during the summer months is due to the azimuth of the sun in those months…the sun rises in north-northeast and sets in the north-northwest. A south-facing array will only get direct sunlight on it when the sun’s azimuth is beyond east, and stops after it passes west. So having north-facing panels will produce useful yield between the spring and autumn equinoxes as it captures the northerly element of the sun’s azimuth during those months. Hope this makes sense?
@@struck2soon yes that's what I thought
Good point 👍🏻
This is especially important the nearer you get to the equator, thanks for confirming this 🎉
You can actually see this in the software plot. There are two peaks on the north with almost nothing at midday.
So they tank in winter?
My install was April 2023 and I worked with the installation company on the design. At that point they were talking about what was needed for the average house so I had to push to max out on panels and battery. I wanted some vertical panels on the rear of the house (SSE side) and some on the north facing roof at the front of the house.
They didn't do vertical mounts and didn't want to do north facing. I talked about ambient light (in the NW of England it's mostly cloudy) and we do get some direct sunshine leading up to sunset.
He explained that sun strength was like standing in a flowing river; side on you don't receive much power so there was little to no value in north-facing panels. I deferred to his knowledge and experience so feel I've missed out on better generation.
Your points about "indirect" or "ambient" light (diffuse irradiance) are well made. Also, in the UK in the summer, the sun rises in the North East and sets in the North West, so there is the opportunity for some direct irradiance on a north facing array in the morning and evening. This effect is exaggerated the further north one is located.
Furthermore, at noon there can be some direct irradiance on a north facing array if the sun is at a higher angle than the array pitch i.e. in summer. This effect is exaggerated the further south one is located.
I have been mulling the advantage of adding an array to the north facing roof of my house (I already have arrays on the south of the house and east and west on a detached garage). At the moment I am hesitating because the north is the street facing side and would affect the look of my house
In 2011, we built a solar system with 560 kWp in Germany with orientations in all four sky directions, south, north, east and west at a roof pitch of 15°, which we still operate today. The northern roofs have an annual yield of around 800 kWh/kWp, the southern roofs 1000 kWh/kWp. Even today I ask myself why it takes so long for the obvious to be implemented?
Hi Gary. Now argument about panels facing away from the sun. But the problem now is the cost of battery storage. As we all have seen, batteries are now below $100 per kWh storage capacity and yet a contractor quoted me a price for a Tesla 13.5kWh power wall 19 times this price. Something is wrong in the supply chain.
We have (to within about 5°) a N/S double garage, set back slightly on the W side of our house. So the S roof is subject to shading from the house up until around midday day. Initially we filled the S facing roof connected via a SolarEdge 4 kW inverter in conjunction with SE optimisers for the shading. In February we took the plunge (because of the low panel prices and no scaffolding required) to get an additional 4 kWp of panels added to the N facing roof. This add on was relatively inexpensive because we also took advantage of the 100% over provisioning capacity of the original SE inverter, so we have the S roof connected on one string & the N roof connected to the 2nd string input. We also had optimisers fitted to the N panels.
Our experience so far that to date the N roof has produced around 62% that the S has. (1.97 MWh N Vs 3.18 MWh S) This figure is higher because of the shading the S roof experiences.
During the long grey gloomy days we've been experiencing the last few months, although still quite minimal, the N roof produces almost identical to the S roof.
During the peak summer months the N roof produces more first thing in the early morning and late afternoon/early evening because the sun does actually rise and fall for a few months to the rear of the house. From the positive results from our garage roof experiment, we are currently talking to our installer about doing similar on our N facing house roof. More costs to weigh up doing this one as the house Solis inverter can only be over provided by 50%, not 100% like the garage SE and we will need scaffolding to achieve it. But we do have the potential to add an additional 14 panels. Decisions decisions!
The pitch of the roof is very important. If more than 30deg, pv production will be reduced. What is the pitch of your garage roof?
Upsidedownfork is an excellent and cadid channel that is straight down the line. I am looking to copy a SSW-NNE roof setup with the majority of the pannels on the rear due to the config of my home!
Time will tell once its up if it will pay for itself or not. Great video and something everyone should consider of fitting panels!
Thanks John! I hope you find my latest video helpful.
Yeah. he’s a stand up guy! 👍🏻
true.
I've got 2 panels (1.1 kW array) on a north-facing roof, just for the test. and compared to my other 50 kW of mainly south-facing arrays it produces nothing, but... in a summer month - 90-100 kWh out of these two panels only made me really scratch my head...
and, in the fog, rain, snow conditions - they produce roughly the same amount (per panel, or per 1 kW of array), not much difference.
well, and still, the only reason to put your panels north - is only if you have filled in every other possible roof (or ground based construction) angle.
I'd still vote for a vertical south orientation on the house facade, but that makes it look a bit awkward...
I have a secondary solar array of 6 panels in the midlands with no shading. 3 pointing NNE and the other three SSW. It is an Enphase array so I can see each panel. Since 1st January 2024 the north facing have generated 698Kwh and the south facing 935Kwh. So north facing 78% of south facing. Definitely worth having.
You still have to consider the individual characteristics of each installation . As well as the pitch of the roof, the individual shading at the ends of the day . A steeper pitch will generate less at midday even in summer , a flatter pitch will get much closer to the south array. But a steeper pitch will do better at the ands of the day when the sun is lower but then shading is more likely to be an issue. In Oval Renewable's example the pitch is relatively flat , but also the front roof is shaded by neighbours at the ends of the day whereas the rear north facing roof which is not shaded will pick up early in the morning and hold later in the evening in the middle months of the year. In this particular case that will compound the advantage of the north array. It's pretty much the ideal case for a north facing array .
Good points-thanks for sharing 👍🏻
With the prices dropping, it’s getting to the point it is cheaper to build fence panels out of bifacials instead of wood, so basically from an install perspective if you don’t mind the asthetics, put a panel there… please though, solar roadways will NEVER be viable 😂
Yeah, new technology is opening up all sorts of opportunities ❤️
Bottom line is to put as many panels up as you can afford, maximise the cost of having the scaffolding up and the installation work, regardless of the orientation. In fact diverse orientations will extend your solar generation day compared to having just panels on say the South roof
On the one hand I wish I had known about this 18 months ago when we got our solar installed. In the early morning and late evening our North facing roof receives plenty of sun.
On the other had our inverter shuts down dozens of times a day in peak summer because of over voltage protection because the infrastructure in the street can't handle the amount of energy generated at those times.
So in that regard we already have plenty of solar. What we really need is an affordable battery and properly integrated software to coordinate generation/consumption between the solar, the heat pump, the EV charger, home automation system and potentially battery.
Unfortunately I've been very disappointed by that. Officially all of the products we got are supported but it's still not working together correctly. And getting support from the vendors has been gruesome.
I live in Belgium, so rules/legislation and available companies are somewhat different here.
This is very interesting. I have no usable east, west, or south roof space and have taken to putting the panels on my shed. But this suffers a lot of shading issues due to very high trees in the neighbour's garden to the east and opposite the property to the west and being relatively low down. All the same, these modern panels and the use of microinverters means I do get usable generation, but having watched this video, I'm very tempted to put a second array on my north facing roof.
Cheers Richard - worth getting a budgetary quote, certainly….
Have you factored in the cost of some copper nails? Can greatly improve your yield
I've got a matched north/south ish array on a shed. Shallow pitch: 22.5 degrees. North manages something like 68% of South over a year. The really interesting thing to me is that on an overcast flat light day i.e. a day when you are struggling for power they generate almost exactly the same energy over the day.
Wow 😮 That’s brilliant!
I live inPhoenix Arizona and my northern facing array generates about the same power during summer as my southern one, because the sun is almost directly overhead. There is quite a bit of drop-off in winter on the northern array, but I don't care since my AC isn't running I generate way more than enough power.
The UK doesn't get direct sunlight anyway so it doesn't matter how you set up your panels as long as it is outside
All fun aside: I am considering a North array too and I am curious how much that would benefit me, especially in winter where there is no direct sunlight. I have excess solar power already in the summer and I'm in no need for more during that time
Spot on Gary. I plastered my entire pure N facing roof with 12 panels a few years ago. Here in Dublin, the return is 55% of pure S facing, so very close to the percentage you got. I got the panels for free as the frames were dented and I did the install DIY with the help of a roofer. They have already paid for themselves and will continue to contribute. I live in a small semi-detached house but with my 44 panels and 80kWh battery and two EVs, I am already energy emissions neutral (I generate 14MWh per year)
14MWH per year for a small semi does not make sense. Here in S England I have 4kw on the roof of my medium sized detached house. I get 4.3MWHvper year. There is space for another 1KW so the potential is for about 5MWh but, even if I put panels on the north facing side the output would be nothing like 14 MWh per annum.
Wow! ❤️
We have a 10.6kwp east west south setup with 36 panels and yield 9.8mwh a year average. Our south array of 16 panels yields 3.9mwh so double the panels you get at least 8mwh, add the 12 north face panels at say 3mwh you can get to 11mwh. It comes down to pitch and local factors so ends up near enough 14mwh.
@@rogerphelps9939it would make sense when you’re running multiple cars from it and full heating. We consume about 3000kWh for our heating & HW alone through an ASHP, and about another 3000kWh on top for my EV.
@@rogerphelps9939 I have 44 full size panels, 10 on my S facing roofs, 12 on my N facing roofs, 14 on my large shed (the width of the property) and 8 on a wall. 16kwp total, generating 14MWh per year. Enough to make my house energy neutral
Apart from the matters mentioned below, another one may be the reduced efficiency of panels that happens as the surface temperature rises. I’m familiar with this, with a group of SSW panels. On hot days around mid Summer, they are a lot less efficient than a typical Spring day with sunshine and showers, and are well within the capacity of the inverter. So, the south facing ones are probably affected by this feature compared with the north facing ones, which may well be cooler much of the time.
I had a similar discussion with my installer over whether it was worthwhile to put a relatively small number of panels on the east and west facing parts of my hipped roof . For me it was a no brainer as I'm limited in number of panels on the south roof by the hipped design and the east/west roofs aren't at all shaded for 80% of the year. Installers concern was disproportionate increase in install costs vs. the number of panels , which is true, but has def. been worth it.
Excellent 😀👍🏻
Great video as always, thank you. Cooler panels on the north side may have helped, also they may have got more light at the cooler times of the day.
Thanks-and that’s a great point. Cooler panels in summer will perform better 👍🏻
Where you are on earth makes a big difference. I am currently at 12 degrees north from the equator. My roof is facing south-east. This video is very interesting for me because in winter the sun is in the south and in 'summer' for a few months it is in the north. My roof is only at about 10 degrees angle. I am confident now, that I will get enough sun year-round.
That’s brilliant!
Lucky you!
Why not do a reverse raise to make the north array face south? We do that here in California.
It looks like you’d only need one row of panels as you’d get about double the output, which might be less money overall as racking is less money than panels.
In the UK, there are building regulations that don't allow for panels to be above the ridge line of the building roof (unless approved by planning permission) You'd probably get away with making a structure to mount the panels horizontal at just below the ridge tile level.
Excellent news. I would consider a video on the performance of different manufacturer’s panels in the same location in dull weather so the panel manufacturer choice for the north slope in ambient light might be different to the south slope panels?
Amazing. Thanks for this info.
My pleasure! Glad it was useful 😀
That was a great video - most of us in the UK have small roofs so makes sense to fill it up. Even if you only get half the generation, thats still adding a third to your overall home’s generation which can have value if you have good export options and helping to cover baseload usage in dull/winter days
Thanks and agreed-especially as energy prices in the UK don’t seem to be coming down anytime soon…
I still don't understand why wall mount isn't a thing here in the USA yet
My stats over the last 12 months (Southampton):
SE 1.17 kWh/day/panel average.
SW 1.03 kWh/d/p av = 88% of SE.
NW 0.72 kWh/d/p av = 61% of SE.
On overcast days (when you really want max solar) all panels produce the same amount of energy from the diffuse sunlight.
Also, if exporting on Flux then the NW are generating when the value of electricity is at a maximum in the evening, so I would estimate that my NW panels have produced maybe 70-75% of the value compared to the SE facing panels. I have 17SE, 2SW and 12NW x 420 Watt panels. I probably could have squeezed on another x8 on the NW roof and slightly regret not doing so.
I have 1 panel opperating as a tester on an ecoflow microinverter, 440w JA Solar bi facial and today I managed a total of 59wh of generation over the 4 hours I managed to get enough generation for the inverter to spit anything out today. This is mostly south facing and it has been pretty overcast with the odd patch of sun. Does this seem right to you? I was expecting more from it, not massive amounts but on a few days it generated literally nothing. If you don't mind me asking, does this lign up with your experiences?
Today (20/12/24) my SE panels generated about 340Wh and my NW panels about 170Wh. Difficult to say whether yours are delivering as expected as you need to review their performance over a longer period 🤷♂️. Also it’s difficult to compare performance between yours and mine unless you live in the same region of the country.
@@Steve-6536 Yes, I'm in the north west and it has been really overcast since install but I did expect better from defuse light. It's only been installed a few weeks and it could be a few months before I have a better understanding of performance but I'm yet to hit 1kwh of total generation over those 2 weeks, which just seems a little off.
They should probably develop north facing panels with prism lenses to bend light from the south, so it’s perpendicular to the panels, especially for spring and autumn months.
That won't work. When the array is tilted away from tthe optimum orienttattion it intercepts less solar energy over itts surface and no amount of lenses will help. We get less solar energy per square metre of ground area in winter for exacttly the same reason.
@rogerphelps9939 Possibly true, I get that the potential solar surface area at a steep angle will be greatly reduced, but isn’t there also the danger that the little light there is, could just bounce off the glass and not reach the silicon ? Surely bending the light down onto the receptive surface would improve things a little, compared to just skimming along the surface ? Id be interested to see if adding a diffuser to a northern facing panel, when sunlight is only just hitting it, would improve things.
Our roof is located in an area with a lot of cloudiness in the transition period between October and March. In diffuse light, my 16 panels on the north side produce just as much as those on the south side. And in summer the sun rises at 45° East. This means I have electricity earlier in the summer.
I like my occupied north roof.
Nice! 👍🏻
Hi Gary. Yip, it’s in the data books. True north against south at 35 degree pitch equals 55% of year round generation. North facing panels should never be overlooked. At home I utilise north facing panels and panels on a flat roof, summer generation ( no export limitation) pays for all electrical usage, heating and 9000 ev miles.
Yeah we have a lot of battery storage and a good import tariff. Your point is good, north facing panels work 😊
Brilliant! Thanks for sharing 👍🏻
For fixed pitch,you need lower pitch lower pitch the nearer you get to equator.
Yeah 👍🏻
Panels so cheap now the cost of scaffold labour and cable is almost negligible in the grand scheme of things adding more panels makes sense
I guess it depends where you live. It cost me £1,200 just for scaffolding two years ago for one orientation!!
I have installed 6.3kWp on our south roof, and 6.3kWp on our North roof, 12 panels on each, and a roof pitch of 23 degrees, the last 31 days the south has generated 105kWh with max power of 3831W, and the North has generated 54.66kWh with max power of 1366W, so this confirms the findings, basically the North generates approx 50% of what the South roof generates give or take. I am however expecting the North to generate a better % when we get to the Spring and summer as the sun will be higher in the sky, and as we have a low pitch on the roof, should get more sun hitting those panels than a house with a 45 degree pitch, system has only been on for a couple of months though hence not much data. Battery is a game changer, we have 32kWh battery which will store any excess production the panels produce in the summer
Mine produce the same. Oh wait, I have 4kWp south and 6kWp north lol. Joke apart, it is reassuring that when looking at the data and trusting science we know what to expect. If only the sales people were more educated. The number of sales guys who tried to convince me not to install anything on my north roof. unbelievable.
Northern panels will also operate at a cooler temperature compared to southern panels - so that would also improve the northern generators’ yield.
Does SolarAzma suite cope with vertical installation and solaredge optimisation?
Solarazma uses PVGIS data so it should cope with all types of installation. What complexities do you see with modelling SolarEdge optimisers?
Your solar fun will kick off in about March 2025
Yeah! Can’t wait ☀️☀️☀️
Will microinverters on north roof be more effective?
Potentially only if there is diffuse shading from a tree or something, I’d imagine.
Microinverters vs solar optimizers vs stringing the array directly into a string inverter is a different issue than this video is addressing.
This video addresses direct vs diffuse radiation. In northern hemisphere, you’ll get more direct vs diffuse radiation, and direct produces significantly more kW than diffuse.
The type of equipment setup you choose depends on other factors than azimuth, most prominently “shading”. If no shade, just go direct into a string inverter. Save money on equipment purchase and fewer points of failure breakdown. Monitor the array product as a whole via the inverter monitoring software. But if your array is affected by shading, think about micro or optimizers, which allow each module to max out kW on its own merits - otherwise all modules within the entire array will sink to the lowest common denominator (aka, the most heavily shaded module).
V surprising! I would have expected more like 25%
I know-I expected the same!
Tech has come a long way in the last 12 years or so. Installing north and south facing panels with a single MPPT would have killed your production. Now, you can have as many aspects as you have MPPT inputs without needing optimisers. Just 2 years ago I paid as much for an optimiser on each of my panels as a 400w panel costs today! Breaks my heart
Yeah, it’s one of the downsides of newer technology-whatever you bought two years is out of date already! But I’d rather have it that way than nothing changing at all 👍🏻
@@GaryDoesSolar absolutely, onwards and upwards!
This is how it’s been with PC’s. Decades ago… wait, and it’ll be cheaper. But go now and you get to use now.
Early adopters vs late adopters.
Pretty much the same results I'm getting. I have East, South and North panels over 5 roof faces totalling 8kWp. Went live on 28th June and have so far hit 2912kWh. This is with 4 of the panels are in a North/South valley (2 panels on each face) and even with the additional shading they are still working well. I'd say the rule of thumb should be to just fill roof to the extent of you budget, starting with the most optimal faces first.
I also did exactly the same - just cover every inch of roof space with as many solar panels as possible even on apparently disadvantageous north-facing roof.
Our roof faces north and south. Had a guest who is an electrical engineer and installer tell us to install on both the north and south sides. We are in a hot part of the world and have a lot of visitors in summer. We heat in winter mostly with a wood stove, and run the heat pump cooling for much of the three summer months. And just having the panels on the roof will cool our house by 5 degrees. Just installing the panels and not hooking them up would probably be a fifteen year payoff!
Painting your roof white has a 1 year pay-back. I am so close to the equator that the sun is in the north in summer. Even if the sun is not in the north in summer, it's going to pretty much straight overhead mid-day, meaning it doesn't really matter what side the panels are on at that time of day in summer.
@@freeheeler09 Jeez…here in the UK we dream of having days warm enough to warrant using a heat pump for cooling!
That’s quite impressive!
I think these northfacing panels don't attribute positive if you also do have south or/and east facing panels. Because they only ad up to the surplus of summer over-production.. In the first graphs it's shown that the northpanels do the worst in wintertime.. compared to the southpanels. I think because the wintersun is too low to get over the top of the roof.. And is coming up south-east and going down south-west. So the sun is not getting "around the corner" !
It would be better to supplement east or west panels to a southfacing installation (if possible). Or wall atached south-facing 90 degreees up panels. So you will catch more of the low angeld wintersun.. So you will add up more to winterproduction..
The placement of solar panels depends heavily on your specific circumstances. Ideally, a south-facing roof with no obstructions, such as trees, is optimal. However, even on overcast days, the orientation of the panels matters less as long as they remain unshaded. Interestingly, some users have reported achieving over 10% efficiency in winter with north-facing panels, highlighting the value of real-world data over theoretical assumptions. Additionally, the performance of your solar panels can vary, as some models are designed to perform better in low-light conditions than others.
@@adus123 What do you mean wit '10 % efficiency in winter' ?
Yeah, North-facing panels should be seen as an addition to panels on other orientations-not as the only orientation.
@@GaryDoesSolar I will question that. It,s more a choice if other options are done. And when the angle of the roof is not to steep. I heard of a case where people didn't,t want panels to be seen from the street.. and the put them on the back of the house for that reason north.
@@eurovisie2010 Yeah, that's fair. Many points to consider--hard to generalise...
Why aren't all new builds built south facing with a mono-pitch roof? Seems logical
I guess buildings have to be built with their orientation to fit with the design plan, but I’m hoping that my video shows that we’re at the point now, where it doesn’t matter which way new builds face now-just cover them with panels and stick a heat pump in and the owners will have low/zero energy bills.
@GaryDoesSolar I get that but a little design tweaking the houses become super-solar efficient. One for the future maybe
This is an interesting point and I was thinking of adding panels to my NE facing roof as I already have the SE facing roof full.
Only thing is I recently installed a battery system that can provide all my daily electrical needs from half price night time electricity so the majority of generation would be exported at only 10p. As I'm paying 14p for the night electricity the difference is only 4p. Maybe a little more if I count inverter losses but I'm not sure that the maths would add up to adding more panels.
Certainly worth doing the numbers to see 👍🏻
Im only using on average 8kW a day, thats inder 3000kW a year. He is generating over twice thr juice to rim my house.
We are fare form energey efficient either. 7 of us in thr house, 2 dogs and a tortoise. Many devices, tv, consoles, laptops electric shower, hob, oven etc...
Im assuming this house has an ev?
I’d keep an eye on your tortoise if I were you-maybe all your generation is going into the heater for it…?
@GaryDoesSolar she live in one of my kitchen 1000mm double under counter cupboards, I've rooted out doors to match my kitchen doors and install one way privacy glass so we can seeing but she not out. They get very excited if they can see out.
Any how is a beautiful enclosure, she wonder the house in the day but makes her way back when tired, she had a door, or rather long ramp with sand paper on it for grip, for her entrance that rinds under the kitchen unit, and exits at the base board of the unit.
Long story short cos the house is at a constant 17-18 degrees, and she had the oven another 1000mm (double unit size) away, her enclosure is easily to keen at a steady temp via a 20w reptile heat bulb.
The bulb is on a timer and a relay it comes on for 14 hours a day, I have a smart thermometer that opens vents if it starts to get too warm.
We basically keep her in summer condition all year round, this way she never goes into hibernation mode. To many complications can come of that. She is about 22 now, so will a round pup.
She will walk up you to sit on your knee while watching TV, and she will change the dogs away if the want a snuggle. We got the dogs used to the tortoise from day one. The two dogs are now 11, so they are all old couples now 😢 if only the lasted as long as tortoise do.
My average overall energy is 8kw a day. I just asked ai how much does that build cost me, and it reckons it's 7 pence a day to run. I thought it would be much more. If I change her time to incorporate the 6h of 7p per kW, I could get that cost down to 4.8p per day
Or if I could store the 7p per kW in a battery and use that back through the day it would go down to 1.8 pence per day.
Also for the majority of the year it cost nothing to feed her, greens out the garden and veg dealings, we only really buy the calcium and vitamin powder as she never took to scuttle bones (I think that's their name).
So she doesn't really coast is anything, £25 in electric and about £3 in vitamins. And a base unit for a super sick house. My wife thought I was mad, but it works great
Excellent overview, thanks.
You’re very welcome. Thanks for the great feedback! 🙏
Gary forgot Northern Ireland on his map, tut!
Didn’t forget-didn’t have any data from there. I do love Northern Ireland though! 😀
@@GaryDoesSolar ua-cam.com/video/IyZnWS00Ym4/v-deo.html Most UK irradiance stats do include NI.
@@FRZ5951 I mean real-world North-facing array data.
@@GaryDoesSolar Ah, I see you've found the one flaw in my argument.
So his north facing array wasnt actually north, and it contained far more panels......than the south facing. yep, well worth it!
Mike, try watching the video again… The Newcastle arrays were due North and South, and the same size.
Why over complicate ? Roughly speaking north facing panels yield 60% of energy yield of identical array facing south. East or West facing arrays yield about 80% of an identical array facing south. One can easily work the energy yield in these situations quite easily using PVGIS or similar websites.
Where did I over complicate?
> Roughly speaking north facing panels yield 60% of energy yield of identical array facing south.
Depends on the pitch. Gentle pitch = more, steep pitch = less. PVGIS will show you this.
@@WyndStryke Not just the pitch, but also how far north you are. I am close to the equator and the sun is in the north in summer and in the south in winter.
Straight north vs straight south gives me 1227.08 vs. 1322.22 kWh/year/kWp that's 93%, but the main difference is that the north facing panels give me only 68.3 kWh in december as worst month, vs. 96.52 kWh in januari as worst month with south facing panels.
They've always made sense.
Explain why please…
@@GaryDoesSolar Because no matter how much panels cost, 'light' will always fall on a roof.
@@kevinholland6841 Just because panels on a North-facing roof will always catch light, doesn't mean they've always made sense. I argue in my video they only make sense today because the lower prices and increased efficiency.
@@GaryDoesSolar I disagree with your reasoning as to 'why'.
They may not make financial sense to some people, but for those looking to maximise generation and carbon reduction they have always made sense.
@@SolarNationUKby your own words then, they haven’t always made sense.
This is a fascinating topic. I had assumed any basically North facing roof would be hopeless for Solar PV.
This shows that assumptions need questioning with real evidence ...
If we get much warmer summer temperatures, no doubt that North facing rooves may be useful interns of operating air conditioning, which is still relatively unusual in UK.
Best wishes from George
Cheers George-and of course, prices will keep falling and efficiencies will keep getting better. It’s all good! 😀👍🏻
Great vid, well presented info. Will definitely consider the NW facing roof I have, another 10x430w panels should fit there....hmmmmm.... :)
If your home only has SE panels now it may be a great solution for kitchen power usage. In summer my SW array can handle a lot, but a friend of mine has SE panels as well and that is basically useless at dinner time.
@SolAce-nw2hf I'm an idiot, I meant NE roof! D'oh
@@justinjoanknecht3475 I have also added NE panels. It makes sense for me as it helps cover more of the yearly usage and in the Netherlands I get the energy tax back for anything sent back to the grid. This arrangement is unfortunately coming to an end in 2027, but by then the array will have paid for itself for a large part, and will continue to support the SW roof on cloudy days for decades to come.
Wowza! 😀😀😀
I am in the process of investigating in a whole roof install, and my house roof is multi faceted including a large North facing aspect. I plan to have a large array on this facet and 5 smaller arrays on the other facets. I will let you know the detailed generation information when I have it. I have based the decision to include an array on the North face based on the videos you refer to in your video, and as a patreon subscriber I will shortly feed the planned install data into your program for review. Thanks again for the excellent content.
🙏 Thanks for your analysis Gary and on this subject I have a few things that I would like to say.
Unfortunately, I cannot compare my system with any of the ones you have discussed for one reason but I'll come to that in a minute.
The first thing that strikes me though is that all of these installations are based on conventional domestic inverters normally only featuring one internal MPPT which has to deal with two different orientations (please correct me if wrong)
We know that this is not the optimal solution as the MPPT has to combine the two sources and average them out so, in your example, the south facing modules would produce marginally more if they were handled by their own MPPT and that obviously applies also to the north facing ones too.
Back to the first reason why I cannot compare my system to any of these which is due to the fact that they are all grid-tied as opposed to mine which is totally independent, at least for the moment.
But just to let you in the picture, I have installed 15 modules on a ground mount, fully adjustable from a summer 28° to a winter 72° in order to potentially maximise the generation and an extra 5 fitted on the roof of my solar shed at a mere 15º.
This also allowed me to confirm what you have just said and, namely the fact in this country the Sun is not always shining as much as it would in Italy where I come from, as a result of which, especially in the winter, they seem to produce more at an average angle, somewhere between 30º and 45°.
The production from the 415W x 20 panels doesn't get anywhere near the figures that you mentioned even though I have two independent and expensive MPPTs, one for each orientation.
Since my system does not export and therefore cannot maximise the usage of the Sun, particularly during the summertime when there is an abundance of it, my 20 kWh batteries are constantly between 80 and 100% throughout the good season and this is probably reflected in the much lower annual readings obtained (around 4500 during the first 11 months), basically use it or loose it.
Unfortunately, I have not yet been able to remove some sheds that obstruct the sunlight in some parts of the year so that also accounts for some of the losses.
I’d like to share with you a brief video (unlisted) of my setup which I have constructed myself even though I am practically new to the game and you will soon realise the cost of it is somewhere between 2.5 and 3 times as much as some others like the one in the UpsideDownFork video, far too much due to my age (72) but I did it mainly as a learning experiment.
Once again thanks for all your videos which I have been following with interest for some time now.
ua-cam.com/video/lExITYwRQOc/v-deo.html
PS) Please forgive my accent in the video.
Hello again! My SunSynk inverter has 2 independent MPPTs.
Some newer inverters are now coming with 3 or even up to 6!
Keep on experimenting!
@@UpsideDownFork I had a feeling that was the case and I was expecting some corrections to my message, I'm glad to hear that especially on the cost front, I imagine that one of those inverters wouldn't cost much more than one of my MPPTs. Things are changing rapidly !
@@9111logic Yes, i'm surprised how much things have moved on in 1 year. Inverters, panels, batteries are all much improved!
Thanks for sharing all this, and for the video link 🙏
I also just noticed about the generation in the winter, you say its only about 10% of the generation of the South, well my generation over the last 30 days has been about 50% of the South, so I think that calculation may be under calculation for the winter months, My panels are not exactly N and S, the South are slightly tilted towards the West, and the North to the East, so that may be the reason why, but I dont think so.
When there is no direct sunlight, my NW and SE perform the same. 👍
Bifacial panels should have been discussed...
Why?
Unsure if this has been considered but we find that the north facing side of our roof generates a thick moss covering which the South facing side does not, spoke to our solar provider (who installed out south facing panels and with whom I am discussing regarding adding north facing panels) and he advised the north facing panels would need to be cleaned once a year
That’s correct less sunshine means more moisture more moss and growth growing
Once a year seems a little extreme.
Whilst hanging Christmas lights, I've been up on a ladder to inspect the NW and SE panels on my house.
After 1 year they are absolutely identical. No build up yet.
I'll get back to you in 5 years time!
@ it would depend if there is trees nearby too it’s not that straightforward I had new panels put up this year March north facing they built up a film in few months. They are only facing first winter now.
@@sweetvuvuzela4634 oh wow! We are surrounded by trees on that side but they aren't too close or too tall.
I am planning to get myself a 30M water fed pole so I don't have to pay the window cleaners to take care of the solar panels for me. 👍
Certainly worth keeping a regular eye on the state of your North-facing panels to avoid any build up of moss etc.
My west/north panels to well. The biggest problem is the suns height. Even when the sun is good it is too low to hit the west panels well and in mid to late afternoon it is too low to get above the other houses. I look forward to the clocks changing each spring/
Nice one!
I think the biggest factor in a north facing array is the pitch of the roof. If it is a gentle pitch (under 30 degrees), then the north array will get some direct light in spring and autumn, and lots in summer, not just ambient light. I have an east/west roof myself, 23 degree pitch. If it was north/south, then the north array would be effective most of the year. If the pitch of the roof is strong (say over 40 degrees) then the only direct light will be in summer, and the overall generation would be far less. Try modelling a northerly roof in PVGIS with a very gentle pitch versus a very strong pitch, and you'll see the difference.
In the video, I modelled 20, 30 and 40 degrees for the Newcastle property and the data stacks well with your reasoning 👍🏻
@@GaryDoesSolar Not sure how I managed to miss that, I saw the 30 degree calculation, but missed the next bit somehow
@@WyndStryke No worries 👍
I have been following the two UA-camrs you mentioned also my neighbour has a north facing array. I am now convinced enough to put them on my north facing roof next year. I have a south facing array installed in 2011. With advances in technology etc over that time I predict the north will produce as much solar as the south lets see 😀
Wow, 2011. Are you replacing those panels at the same time?
One of my neighbours also has some blue panels on his SW roof, but installed about 7 years ago if I remember correctly.
Replacing those panels with modern ones should add nearly as much yearly production as adding new panels to the NE roof.
Another option is moving the older panels to the north facing roof, but I am not sure that is worth doing.
@ They are untouchable until 2036 as they are linked in to a very healthy feed in tariff 😀
@ sometimes it's just easier having no choice. Panels should be super in 2036.
What would your choice be without the feed-in tariff?
Fantastic! And good luck, Simon 😀
@ Thanks Gary you and your fellow UA-camrs have given me the confidence and knowledge to go all electric with solar battery storage and air to air heating plus Mixergy water tank. Apart from UA-cam advice has been difficult to find.😀
Just remember, Fork is down South. Where you in the Country will have a massive bearing on yield.
In the video I have data from Newcastle and Oxford. Not sure where UDF lives…
Definitely have panels all round.....
I have 4 panels ~25' (NNE); 3 panels ~115' (ESE); 4 panels ~205' (SSW).
(30' pitch, Region 7E) 4.83kWp
I've only had these since early October, but can already see that the decision to include the north has been the right one.
Yes, as we approach the solstice you'd think you wouldn't bother with any of them, however I've seen some surprising days. On average, so far, I've seen the NNE generate about 20-30% of what the SSW produce. My ESE is fairly masked by the (close) house next door, but they do come alive again a bit later on. With the sun now so low, even my best panels are poor as they are masked by houses on the next street. I've been taking daily LUX measurements at about the same 'start of day' time to help reviewing my generation log.
So far, my bigger 'winter season wins have been from battery charging in the cheap rate period, and deferred washer runs to that time. My costs are about 60% of normal due to all of this. I've not yet really decided on tariff as it's all new to me, so I started on Flux for a start. (I have a PHEV, but neither it nor the charger match the Go tariff).
My feeling on battery size is that I'd aim for about twice your average daily usage for battery capacity. So for me, I'd want 2x10kWh. I have a PW3 (at 13.5kWh) and will be adding one expansion pack when they become available next year ~ Tesla say they are due Q1-2025 in the UK.
Thank you, and all the other UA-cam channels for your combined advice.
Probably worth looking at the Cosy tariff if you’re eligible as it’s unlikely you’ll be exporting any excess solar during the winter months. Cosy gives 3 sessions at about 12.5p/kWh so you can keep refilling your battery. Works really well if you have a heat pump(s) but might also suit your PHEV too 🤷♂️.
Thanks for sharing all this-will help many people, I reckon 👍🏻
You need to compare generation for an average summer day between the N and S facing panels. That will show why the N ones contribute more in summer (early morning and late afternoon). This may be useful for some people but if you are already generating more than enough from your S facing array, then you will be sending it back to the grid (or batteries) and then the economics depends on your tariff. In the winter the extra generation is much less but may be of interest if your S array is limited.
I’m hoping to get real-world monthly data for the Newcastle property…
Another great lesson for a caveman like me - keep it up Gary; superb content!
Cheers Jim 😀👍🏻
Recently seen a video about Solaflect EV Charging. Their unit is mounted on a pole using stay wires to transfer most of weight to pole allowing for lighter frame. It follows the sun. If we could place units like this on new housing, it would not add weight to roof, pole could be in center of house allowing for short runs from batteries saving on cabling costs. Bifacial panels and a white roof would increase performance.
I’ll check this out…
Try Bi-facial panels vertically mounted.
The back side can pick up from ambient light. ( especially if the back side is a lighter color. ).
I’m going to be looking into bi-facial panels soon…
I would be a bit concerned when a violent storm passes by.
@@ianbigsand7 Such a storm would be a problem for a house roof anyway...
@GaryDoesSolar I'm imagining that vertical bifacial panels would be mounted on the ground, the flexing on a larger panel would be substantial. Roof mounting will give a large measure of protection from the wind.
I did see in the recent storm that a large solar farm did suffer damage. How did domestic installations cope?
@@ianbigsand7 Ah yes, apologies - I misunderstood... You've got me thinking about my own garden fences-there is typically always some kind of damage after a storm...
One more reason why north facing panels yield relatively more energy in the summer compared to to the South facing is due to South facing panels heat up much more than North facing panels - so there is a loss due to temperature that occurs on southern angels which northern ones wouldn’t incur (or incur much less of it)
Yeah, I could believe that-good thinking!
I have almost exactly what you are looking for. I have a 3.2kw South facing array and a 4KW North array: I would be happy to share the real world data with you.
Thanks Adrian-that would be great! My email is me@garyDoesSolar.com 🙏
Interesting video. Next, it would be insightful to explore the performance of panels installed on walls facing west or east. Many still overlook fundamental principles of physics in such discussions. The critical question remains: what is the cost versus return if these panels are considered purely as a financial investment?
Yeah, all good analysis to be done 👍🏻
@GaryDoesSolar as you may remember, I have 3kWp on my wall facing West. Unfortunately the last few weeks it has been only thick clouds after thick clouds... I'll send you my 12 months data if you are interested
@@NacNacMOTT I'd be very interested--thank you! me@GaryDoesSolar.com
But I bet that 50% is in the summer, when you don't need it, and zilch in the winter, when you do need it.
@@grahamcook9289 yes, but this is true of all solar yield…we consume the most electricity during our panel’s lowest yield period.
Export rates make it worthwhile at the moment. How long they will last is anyone’s guess though I suppose
@@Crazydiamond_1974 But to export you have to remain connected to the grid and suffer the ever increasing standing charge.
Yeah, but is that a reason not to do anything?
I think OK but remember you get a lot extra in summer when you dont really need it and not a lot in winter when you do need it so I think it's good for some but not all.
Thats why you need a battery to store that extra energy to sell back to the grid
@@kevindavis8442 If you are selling back to the grid, why need batteries?
I also have panels on the NE roof. They really help when clouds disperse the light and the SW array struggles to power the home by itself.
Everybody’s situation will be different, I guess. But I hope I’ve shown that in the general case. North-facing panels make sense now.
There is another greatly missed calculation that needs to come into this and that is your Latitude, I am in the southern hemisphere in Australia and at about 33 degrees, I have just gone off grid, but for 14 years was grid connected and had arrays that were east, north and west, between the north and the other two arrays, the north was only 10% more output
There’s no denying it - have a latitude closer to the equator helps enormously 👍🏻
Brain exercise. If my home is at the north pole, which produces more annual energy, north or south array? If my home is at the equator, which produces more annual energy, north or south array? If my home is at 45 degrees do entire roof?
My brain hurts just thinking about it…
At the equator it won't make any difference. If you are exactly at the north pole, then every direction is south :-)
That's not quite right. Given a fixed budget to cover only one side then S facing panels is the obvious choice. If you have a budget to fill your entire roof N and S then you will get a bit more generation. Whether it is economic to do so is another question. Nobody would put panels on the N side and leave the south side empty.
Go back and watch the video. No one is suggesting you only put Solar panels on your north side roof only. He is saying if you can afford the additional cost which may not be that much more. Then it may be beneficial to have them on both sides
Wot @adus123 said…
I've started looking at this myself for my garage roof after watching UpsideDownFork. And I agree... I think it's worth doing though I would like more data on the summer/winter differences. His data was whole-year, but that will skew towards summertime operation.
I’m going to see if I can get monthly data for the Oval Renewables property
Month by month data now ready!
ua-cam.com/video/hmnXZvdypvk/v-deo.html
@@UpsideDownFork Thanks! Zipping over to your new video!