Solar panels are installed differently based on their geographic locations throughout the world. The premise behind this is simple; the sun is in a different place in the sky, so panels need to be directed according to this positioning. The ideal situation is when the sun is hitting the panels at a perfectly perpendicular angle (90°). This maximizes the amount of energy striking the panels and being produced. The two factors that such an angle is controlled by are the orientation (North/South/East/West) and the angle of the panels from the surface of the Earth. So in Australia, what angle and orientation are best?
(Get a free comparison of solar quotes of the installers who operate in your area!)
Tilting
The tilt involves primarily the angle that the panels are facing up into the sky. On a flat roof, the tilt is 0°, whereas if the angles were to be facing a wall, it would be 90°. As indicated in the above diagram, an angle of approximately 32° is the best, but anywhere between 20° and 40° is optimal for around a 90% efficiency. As soon as a panel is tilted below 5°, efficiency will become an issue, as well as if it is placed at an angle larger than 60°. All in all, tilting is an important factor, but not as important as the orientation can be.
Orientation
Australia, being in the Southern Hemisphere, experiences a sun that is predominantly coming at us from the North. There is of course deviance throughout the seasons, but ideally solar panels should be facing as close to true North as possible to reduce the impact that the Winter seasons have on efficiency. Once again referring to the graph above, one can see that even North Easterly and North Westerly facing panels will be largely operating at around the 90% of their rated outputs. However, once angles start approaching East North East or West North West orientation, the numbers start reducing rapidly. A directly East or West facing panel will never operate at better than 85% of its rated output. To put this in perspective, rather than getting back the usual 4.5kWh average daily energy per 1kW of solar, the system will only produce 3.835kWh. For example, a 3kW system would lose a full 2kWh a day if it were facing more East or West than North. This would equal 88c worth of surplus energy in QLD and SA a day, $1.20 in surplus to Victorians, a minimum of $1.00 less in the ACT and $1.20 in NSW. A lot of energy that is not captured, and a lot of money that is wasted.
Read more: East vs West orientation for solar panels; which side is better?
Why tilt frames are a justifiable expense
So we can see that both of these factors are important in their own right. What the majority of houses and installations need to remember is that a combination of a not so great orientation and a poor tilt will add on to one another, making the consideration of both factors the only reasonable way forward. Tilt frames that counteract a sub-optimal tilt and orientation will cost you a little extra. How much will depend on how many panels make up the system, and how the installer sources and prices the labour and parts required. The bottom line is that the bigger a system is, the more justifiable that expense becomes. With a 1.5kW system and below you can get away with forgoing the frame, but anything larger and the fact is that the cost of a tilt frame will be paid for with the increased efficiency and day-to-day output of your system. Shopping around to get a number of quotes is the best way to find a reasonable price for the frames, but expect to pay a minimum of $400-$500.
Jarrah Harburn
Solar Broker
Solar Choice Pty Ltd
© 2010 Solar Choice Pty Ltd
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i have a nth facing roof with a solar hot water system on it , it gets approx 71/2 hours of exposure to sunlight/ UVA when cloudy. What is the optimum amount of exposure, for my roof its from just after 8.00am till almost 3.30pm where the suns rays then hit the pecan nut tree on the westerly aspect., where the shadow from the tree then begins to creep across the roof. I,m on the Sunshine Coast Queensland Please could you tell me….. Thankyou.
Hi Chris,
Not quite sure what you mean by ‘optimum amount of exposure’. It sounds like you’ve already got the optimum arrangement, all things considered: north-facing roof and exposure to sunlight throughout most of the day. Unless you want to cut the top off of your pecan tree, there’s not much that you can do. Keep in mind that your solar hot water system is insulated and will in all likelihood keep the water warm even after the sun has stopped shining directly on the system. I hope this is helpful.
cool :D
Thanks, Brandon!
Hi, I have a North facing house in Adelaide with no room on the N facing pitch and plenty of room on the W and E pitched sides. There is a 5*4 mtr flat space (5 wide E to W & 4mtr deep N to S). I’m weighing up placing panels (2kW system) on E or W face vs on the top flat space on 2 rows of tilt frames facing N. I’ve heard you need min of 2.5 mtr between rows to avoid shading issues with the front row casting a shadow on the row behind. My installer tells me you need min of 1.8 mtr between the pivot points to avoid shading issues in winter and that I have plenty of room on this space to do this. Panels are 1600*800. Or I could just install on this flat space laying flat. I need to decide if it is worth the hassle to do the tilt-frame and go through council. The cost and hassle of frames facing N I think would be justifiable providing I have enough space to avoid the front row shading the back. Any comments greatly appreciated.
Thanks very much for commenting on our blog. If the panels are set to face due north then the spacing between frame mounted panels is indeed 1.8m, this should allow you to comfortably fit 12 to 15 panels on the 4m x 5m flat roof.
As far as justifying the additional costs associated, here are some figure’s to give you an idea.
The South Australian state government are implementing, at some stage this year, a 0.54c/kWh net feed in tariff, based on this feed in tariff and the very conservative expected daily output of a 1.5kW system in Adelaide of 6.3kWh/day, you could expect a maximum return of $1211.11 per year. Over the 17 year period which this feed in tariff is scheduled to cover this equates to $20588.90. Placing solar panels on a due east or west facing roof is estimated to reduce system efficiency and production by 15-20% which at very best would reduce the return over these 17 years to $17500.57 a loss of $3088.33. Please keep in mind these are based on maximum returns from a 1.5kW system and would, depending on your power usage by day, be realistically more like half this. However, the life of the system will far exceed the 17 years and therefore the long term return figures will be more extensive.
Hope this was helpful!
Hello,I am having a 1.5kW system fitted to my flat roofed home in Nelson Bay NSW. The roof is in almost full sun all year round.For aesthetic reasons i am contemplating having them fitted flat on the roof,can you shed any light(pun intended) on what performance drop i could expect by not using angled stands. Thanks in advance–Bruce
Hi Bruce,
Thanks for commenting on our blog. You would ordinarily expect about 5.5 sunshine hours per day (averaged over the year) in your location. If the panels on your 1.5kW system were tilted at the optimum angle–about 30 degrees in Nelson Bay–you could expect about 7.4kWh/day, assuming a minimum efficiency of 90%. Depending on the orientation and the angle of the building in question, your efficiency could drop lower, though, especially in the winter months when the sun is lower in the sky to the north. If you fill out a solar quote comparison form or call 1300 78 72 73, one of our brokers can give you more details.
Hello, I am considering installation of a 3KW system in Launceston.
My roof is at 25 degree pitch and faces 300 degrees on the compass.
It gets app 25% partial shading from about 1pm to sunset in winter and full sun in summer.
What efficience lose will this cause?
I see by your graph the system would be running at app 90% efficience.
But launceston is at 41.5 dedgrees south not 35 that the graph is based on.
Thank you
Hi,
I’m thinking about getting a 2.66kw solar panel set up for my house. I live in Brisbane and the only part of the roof that will fit it is on the Western side which is approx 260 degrees off true North. So its actually 10 degrees past West heading South. Would tilt frames be a worthwile addition or is the set up not going to be cost effective regardless of tilting.
Thanks
Craig
Hi Craig,
The southerly aspect could potentially be a problem for your production. For a system of that size you could still stand to benefit even with this less-than-optimal orientation, but the payback period would be longer than a north-facing roof. Tilt frames would probably need to actually tilt the panels background, which leads to stability issues and may also increase price.
We can offer you a look at what systems are on offer from a number of trustworthy installers that operate in and around Brisbane. Request a free impartial quote comparison or give us a ring on 1300 78 72 73.
Hi. I live in Bridgewater, South Australia. I am having a 3 kw system installed on an East facing roof which is at an angle of about 15 degrees. I asked about the use of tilt frames to direct the panels on a northerly angle but they advised that this was not viable. I would appreciate your comment on this as I am keen to get maximum efficiency from the system.
Thanks
Roger
Hi Roger,
Your installer is right that it may not be a viable option to put tilt frames on an east-facing roof to change their orientation to north, unless perhaps the slope of your east-facing roof is very slight and close to horizontal. This type of drastic adjustment is not standard industry practice, and could result in array instability. If you are interested in getting the most out of your system, you may want to have a look at some of our previous blog entries: Inverter sizing and efficiency, how much energy will my solar cells produce, and how to troubleshoot your system for efficiency.
You may also want to get in touch with us directly, as we are always keen to help and can give impartial advice on what systems are on offer from different installers in your region and at what price. You can fill out a free quote comparison request or give us a ring on 1300 78 72 73.
Hi. We are in Brisbane and planning on connecting a 3kw solar system on the Eastern side of the house. The alternative is a 1.5kw system on the front (Northern side) of the house, but problem is it may not fit there. How efficient are systems facing East? I’m wondering if a 3kw system on the Eastern side is going to produce much more than a 1.5 system on the Northern side? We may be able to squeeze it in on the Northern side. Thanks for any advise.
Mark
Hi Mark,
Thanks for the comment and the question. It’s a good one. We have more recently written another article about east vs west orientation for solar panels–have a read, as it might be of some assistance to you. You could also give us a ring on 1300 78 72 73 or fill out a free quote comparison request from Solar Choice to get a clear idea of what sorts of systems are available.
In any case, providing there is no shading, the larger 3kW system on the east-facing roof would almost certainly produce more (although not much more) power per day than the 1.5kW system on the north-facing roof, but the return on investment per kilowatt is likely to be a bit longer, because your panels will only see about half the direct sunlight than they would otherwise, and you will have paid more for that system. But then again, your system will be half the size!
Here’s a quick estimation of what you can expect:
Brisbane gets an annual average of 5.4 Peak Sun Hours (hours of sunlight) per day. As a very rough estimation, let’s say that a north-facing array with no tilt frame gets 4.7 of these, and an east-facing array gets just over half of that (although this would depend on the angle of your roof)–2.7.
The 1.5kW system would produce 1.5kW x 4.7PSH = 7.05kWh/day
The 3kW system would produce 3kW x 2.7PSH = 8.1kWh/day
As you can see, with this back-of-envelope calculation there doesn’t seem to be a huge difference in system output.
Please keep in mind, though, that these are only estimations, and the actual solar system output would depend on a number of factors; you can read about these in our previous article about troubleshooting solar power systems.
i am planning my home extensions in sydney and need to decide whether to have an open gable end on the north facing rear of the house. This was to allow plenty of North winter sun into the living areas and entertaining deck. However this would eliminate any north facing roof surface on which to mount solar panels. Would I have the option to mount panels on the east and west roof surfaces and tilt the panels slightly to the north? The current roof pitch is about 25 degrees.
Hi Richard,
Thanks for commenting. You can read a bit more about East-West roof orientation for solar panel arrays in another article of ours. Ideally, due north is ideal, of course, but if you can’t manage due north, then it’s also possible to split your array between east-west, although this will probably drive up the price of your system per watt because you’ll need two inverters or one inverter that can handle two strings.
That being said, a north-facing aperture that will let in the winter sun will actually be useful in reducing your heating/energy costs during the colder months, provided the building is well-designed and well-insulated. You are in a fortunate position, in that you have control over how your building is constructed–you might want to read up about passive solar design before you go ahead with building. Taking a holistic view and designing your building to be energy efficient as a whole is one of the wisest, and most cost-effective, things that you can do, especially if you are considering eventually putting on solar panels and want to make every watt count!
Solar Choice offers free quote comparisons from different solar installers in your region and nationally. Or feel free to give us a ring on 1300 78 72 73.
I currently have a 2.7KW system and i am only getting 6.92kwh a day from my system. My system is located on the North West Side of the roof and there are no trees or any form of shading. Does this sound right because i don’t think it sounds right i feel that i should be getting more out of this size system.
Hello Doctor,
Thanks for commenting. Your electricity production will depend first of all on your location. We are in the middle of winter at the moment, so the days are very short. This means less potential to generate electricity per day. If you are in Melbourne, for instance, you can only expect 2.7 peak sunhours (PSH–cumulative hours of optimal sunshine) on average for the month of July.
2.7 PSH * 2.7kW = 7.29kWh
Once you factor in system inefficiencies (voltage drop, heat derating, dust, etc), 6.92kWh sounds like it’s in the right ballpark. You should expect to see greater production in the summer months. Keep an eye on your system output, for sure.
Of course, if you are further north than Melbourne, your production may indeed be a bit low for the size of your system. In which case you may want to have a look at our solar power system troubleshooting article.
Hi
I am thinking to put 3 kw solar system in my house. I dont have north facing roof. but i have 15 degree pitch facing easy and roof area is not a problem. Is it possible to add adjustable tilt kit on east side of roof but glass of panels and tilt kit facing north .
Thanks
Hi Jimmy. Thanks for the comment. What you’re talking about is technically possible but probably not ideal in terms of physical stability: if you put your panels flat on a roof with a slope as low as yours, you might actually capture a surprising amount of sunlight, although you will lose some productivity in the late afternoon.
Please also read our article about east vs west orientation for solar panels.
You can also ring us on 1300 78 72 73 or fill out a free quote comparison request form to commence a dialogue with one of our brokers.
Hi, first off, love the website, I’ve let a few people know about you!
I live in Melbourne and I’ve had a 3.4kW installed on my roof in May 2011 and from comparing my output to a friend of mine, who has the same size system, found that my system wasn’t producing anywhere near as much! So I got on the roof at midday in late June and found that the first row of panels (12 panels) is shading my second row (6 panels)! The amount of shading was about 10% of the entire 2nd row. I have called the company that I bought the system from and they are proposing to lay the front row down until this fixes the problem. My question is, what efficiency drop will I incur in doing this? The rows of panels are spaced at 850mm apart (clear gap) The angle of panels currently is 24degrees and the array is pointing 10degrees off true North (to East). From my calcs, they would have to lay the front row of panels down to about 13 degrees. On reflection, the layout on my roof is such that they could have had the first row with 6 panels laying on their side and the second row with 12 panels but I feel they didn’t have the right tilt kit in the first place. So now I’m looking at a substandard install and would like to know how much this will affect me. I’m considering my options but I see that there may be only 3 options, 1. raise the entire second row up. 2. reconfigure the whole system on the roof space or 3. add more panels to cover the efficiency drop – their expense. Hope you can help!! Also if I don’t get a satisfactory outcome, who should I contact regarding matter like this!!
Hello Kippo,
Thanks for the comment. It sounds like someone didn’t think through your install in the first place if one row of panels was shading the one behind it.
How closely clustered together are the panels on your roof, and how much space do you have to move them around?
The best and most simple solution would be to just move the second row of panels up the roof so that the first row does not cast any shade on them. This way you wouldn’t have to compromise the output of your array by changing the tilt angle of the panels in the first row, and you wouldn’t have a shading problem. Is this an option for you? I suppose this would be option 2 in your list. Totally reconfiguring the whole system could mean rewiring and changing your strings of panels around, which would make things a bit more complicated (and expensive!) than you’d probably like them to be. Have you got a quote on moving the 6 panels further up on your roof?
Once you do get a quote on moving the second row of panels up, you’ll have to compare what that would cost you, to what sort of efficiency (and therefore money) you might stand to lose if you instead decided to change the tilt angle of the first row. I imagine that changing the tilt angle of the first row would probably be the most cost effective option, labour-wise? Have you got a quote on this as well?
By the way, you’re right in feeling that the tilt angle wasn’t quite right–it should be around 30 degrees for most areas in Australia–where are you located? Lowering the tilt angle will likely result in efficiency losses, although possibly not major ones. Shading is definitely more of a problem than non-optimal tilt, especially if it’s happening for a good portion of the day–even just an hour during peak sunshine time. As you’re probably aware, with mono and poly crystalline solar panels, there can be significant efficiency losses from even partial shading, disproportionate to the percentage of your array that get shaded.
I wouldn’t consider adding more panels to the array–you should work with what you’ve got! Adding more panels would mean reconfiguring the whole system anyway, and may further complicate matters and result in you paying more money for both labour and components in the end!
Hope this was helpful!
Best,
James
I had 8 x 190w solar panels fitted at an angle of 14 degrees to produce 1520w, the actual max rate obtained at local noon is 1100w (cloudless days) I now wish to tilt the panels to their optimum angle, can you advise what angle I should be aiming for?
I noticed on a couple of sunny days with a scattering of low fluffy white clouds that the charge rate for a few moments reached 1520
Love your blogs, Great info in them.
I am in Southport Qld Lat 27:58S Long 153:22 from Satnav
Hi Joe,
Thanks for the comment. We’ve received quite a number of questions similar to yours–about what to do with underperforming solar systems.
The problems with your system could be due to a number of factors (read our solar system troubleshooting article), but it sounds like the tilt angle could be playing a part in the case of your system. Why did you decide to tilt the panels at 14 degrees? Is that the tilt angle of your roof? Such a near-horizontal angle is not bad for the summer time, but ideally you’d have a tilt angle of 27-32 degrees where you are, at your latitude.
You might have saved some money by not getting tilt frames (if that is indeed the reason you decided not to get them). When you were considering getting a solar system, did you do a cost-benefit analysis over the life of the system to determine whether they would be worthwhile?
Thank you for your advice. The 14 degree angle is the angle of the roof section that the installers chose, and when I questioned this I was informed that this was a very good angle and that I did not need tilt frames. No cost-benefit was done, I just relied on on the installers advice.
Joe
Add to my previous comment, the panels face 10 degrees east of north.
Hi John,
The ’10 degrees east of north’ factor would be less important than the tilt angle in your case, I think. Let me know how it goes.
Hi
I notice that you havn’t answered Wayne’s query from Launceston. Well I am even further south, in Hobart, and would love to know the answer. How can the same tilt angle of 30 degrees be the same all over Australia? In Darwin, being north of the Tropic of Capricorn, panels at 30degrees would get just about zero sunlight in the middle of summer. For a solar hot water system the recommended angle of tilt from the horizontal equals your latitude, ie for Hobart this is 43degrees. Is it the same for the photovoltaics panels?
with thanks
Ric
Hi Ric,
Thanks for the comment. You’re right that tilt angle should vary depending on your latitude–for many places in Australia, this means about 32 degrees.
Generally speaking, if you’re not in a tropical latitude, you should tilt your panels at about the same degree as your latitude. However, in tropical latitudes, as you point out, panels should be closer to flat because the sun can actually go ‘below’ the panels if they’re tilted at too high an angle: during the change of seasons, the sun is sometimes south and sometimes north of the panels, whereas in higher latitudes the sun is always on one side of the panels.
The below table is a a good rough reference for tilt angle relative to latitude.
I wish consumers were provided with some more realistic information regarding what happens when your electricity tariff changes from standard rate to time of use.
I’m in Melbourne, with AGL, and had a 1.5kw system installed back in early March, but after a few rough calculations I declined to get my meter changed from a standard 2 rate meter to a TOU/Smart meter, or sign up for the feed in tariff.
Now after carefully tracking my PV output and electricity usage for 6 months, I definitely made the right decision.
I consistently use about 19kwh/day over 12 months, and use on average 65% of that, or 12.4kwh between TOU peak time, 7AM-11PM. That includes the hours the PV panels would be producing output. Because my panels are not true north, I reckon I should be getting about 80-90% efficiency, but so far its only about 50% of what the table says it should be. Even with that, I would only be about $0.22/day better off on TOU, and I may be able to save an extra $0.66 on the weekends. I reckon I need at least a 3kw system to consider going to TOU.
Is there a way to feed back into the grid without getting the feed in tarriff or going on TOU billing?
Hi Paul,
Thanks for the comment. You make an interesting and valuable point.
In Victoria one of the requirements for eligibility for the premium feed-in tariff is getting a Smart/TOU meter, so for you there isn’t at the moment any other option for feeding into the grid through the major retailers.
You could, however, inquire with Diamond Energy to see what options they have available for solar feeders-in in Victoria. They are a renewables-only electricity retailer.
CAn I split the panels ,I can fit only 2 in the north, rest will be in the west facing
Hello Malar,
It is possible to split the panels across more than one roof, but you’ll need to be careful of how the ‘strings’ of panels are arranged. Read a bit more about ‘centralised MPPT inverters‘ here. It is important that all panels in one string be producing the same electricity output–mismatches lead to inefficiency. You might have an inverter that can take two different inputs and equalise the difference using MPPT (maximum power point tracking) technology, though, in which case you may be able to put the different strings of panels on roofs with different orientations.
You may also direct any questions that you have to one of our solar power brokers–Solar Choice offers free solar power brokering and solar quote comparison services. Request a solar power quote comparison.
Read more about solar panel tilt and orientation in Australia.
Read more about solar inverters.
Read more about troubleshooting your solar power system.
I’m looking at a 1.1-1.5kw system, but I’ve got an east/west facing roof with 30 degree pitch in Geelong. How do I go about getting the most Benifit?
Hi Tim,
Thanks for the comment. Generally speaking and barring any shading issues, west is the better orientation for a solar system, especially if you are on a time-of-use electricity plan with peak and off-peak rates. (Read the full article: East vs West orientation for solar panels.)
If you have any other questions, feel free to give us a ring on 1300 78 72 73 or fill out the Quote Comparison Request form on the right of this page to initiate a free, no-obligation dialogue with one of our brokers.
I’m located in Labrador, Gold Coast and have a south facing roof as part of a duplex. I’ve been told varying options for panels for this elevation. Some have outright told me that they will absolutely not install panels on south facing elevation, others have said if I lay them flat on the roof with the 22 degree pitch then I am down to 78% functioning, or I could elevate them with a tilt kit.
However, someone else said that that is suicide for our roof in case of a strong wind or storm as you have a V shape on the roof now with the wind having nowhere to go.
Who do I believe? That is the question I am posing to you.
What is the story with a south facing roof for panels when you have no other option available to you?
Will the tilt system be safe enough to withstand wind when in this V configuration on the roof?
Thanks….
Hi Vikki,
Thanks for your comment. Different installers have different capabilities, equipment and levels of experience. Some might be hesitant to install tilted panels on a south-facing roof, but others might have experience doing so and be comfortable with it. In any case, standard tilt panels will probably not give you the ideal angle for panels on your south-facing roof; you will probably need to have them custom made, which will likely incur additional costs. Although strong winds may be an issue with the ‘V’ shape formed by the panels and the roof, if engineered appropriately (i.e. spaced so that there are gaps between and underneath panels for wind to pass through) installing panels on these kind of tilt frames would not be an unacceptable risk.
Please fill out our quote comparison request form to get a comparison of prices for solar systems in your area. One of our solar energy brokers will be in touch with you about your options. There are installers in our network who have experience with tilt frames and may be able to help you out.
I’m limited for space on my roof. Do all solar panels in the same bank or split banks need to be aligned in the same orientation ?
Hi Maurie,
Provided you have an inverter with dual maximum power point tracking (dual MPPT), it’s all right for you to have up to 2 strings (‘banks’) of panels aligned at different angles. In this case, each string will be tracked individually, and the power from both added together. Otherwise, the weaker string would drag down the stronger one. If your inverter only has 1 input, on the other hand, it would not make sense to install the arrays at different orientations/angles.
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