East or west orientation for solar panels? What to do when north is not an option

By Jeff Sykes on
Architect designing solar

Determining the orientation and tilt angle of your solar power generation system is one of the most important considerations in designing your solar power system. As we have mentioned before, in the southern hemisphere, due north is usually the best orientation for panels. But not everyone has a perfectly oriented roof. When your two best options are east or west, which should you choose?

The sun’s movements throughout the day

During the course of a day, the sun passes through the sky in an arc that varies throughout the year due to the earth’s orbit (see top image). The arc is always symmetrical from east to west, measuring out from the centre point, which would be midday. This means that from sunrise to midday (not counting during daylight savings time) and from midday to sunset, there is an equal number of hours of sunlight on one particular location. (You can see how this applies to your location using applications like SunCalc, which shows you exactly how the sun moves through the sky at different times of day throughout the year.)

So, if your home or roof does not have any north-facing roof space available, but does have two sides that face east and west, you may be asking yourself which side would be a better location for the most power generation. Making the right decision will impact on how much money you can save with your solar panels.

Compare quotes from up to 7 installers in your area now.

Look for shading

The first thing to consider is shading, of course, which can potentially have a big impact on the productivity of your system. Is either side of the roof shaded by nearby objects? If one side is shaded, choose the other side.

If you’ve determined that the shading effects are either non-existent or basically the same on both sides, then the next thing to consider is the angle of your roof – if possible, you don’t want to have to put in any mounting brackets or solar trackers. The two sides of your roof may be tilted at different angles: you will want to choose the side which is closer to being horizontal, as this will result in the most insolation (incident sunlight) throughout the day.

Fun fact: Even a south-facing roof can work for solar

Check out our article about south-facing solar panels.

Are early morning or late afternoon clouds a common occurrence?

So, you have determined that shading is not an issue, and that both sides of your roof are symmetrically angled. What do you do now? Although Australia is well-known for its unpredictable climate, you will need to consider when you tend to have cloudy weather more often–in the morning or in the evening.

This will depend on your location and climate, but for many locations (including Sydney), mornings have a greater tendency for overcast skies. Shading, even from clouds, can reduce the output of a system by up to 90%: any time it is not sunny, energy production will drop.

So, in essence, the answer is that you should try to put your panels on the ‘sunnier’ side of the roof in terms of weather: if you have cloudy mornings more often, the west-facing roof, and if you have cloudy afternoons more often, the east roof. You can check out the Bureau of Meteorology’s website or use NREL’s PVWatts tool to get a clearer idea of which direction is sunnier.

Are you on a time-of-use billing arrangement?

If you are on a time-of-use (TOU) electricity tariff, you are probably thinking strategically about power consumption and pricing. Because most households use more electricity during the afternoon – when it is more expensive on TOU billing, a west-facing solar array is probably the better way to save money.

For example, in NSW the price of electricity between 2 and 8pm on weekdays can be around 45c/kWh (or more), which is nearly three times the off-peak rate of about 12c/kWh (usually the wee hours of the morning). If your panels are west-facing, you will be producing more power right during the expensive peak times than you would if the panels were east-facing.

Time of use tariff schedule as displayed on the Reposit First monitoring app. Afternoon peak prices are higher than shoulder or off-peak prices at other times.

West-facing may be the better option even on a flat-rate tariff

Also keep in mind that household electricity consumption tends to be greatest in mid to late-afternoon (read more about electricity consumption patterns). So even if your electricity price is the same every hour of the day, you could still potentially save more money with west-facing panels, because their production will ‘peak’ slightly later than a north-facing panel array would.

Compare quotes from up to 7 installers in your area now.

See current & historic solar system price ranges for each capital city: Solar Choice’s PV Price Index

See the rest of our calculators in our Calculator Resource Library

Jeff Sykes
Latest posts by Jeff Sykes (see all)

Related Posts

Comments

  1. I cant get past the point in this where it says that a north facing roof is the preferred setup. Are we talking from a southern hemisphere point of view? I know that for ALL of North America the preferred roof facing is the South. Since the suns angle is from a Southernly view for the winter, and during the summer it is more directly overhead. So why is a Northerly facing roof preferred? Am I missing something?

    1. Hi Mike,

      We are an Australian business and this site focuses on Australia. For the northern hemisphere, you’re correct that south-facing is ideal.

  2. Hi, my house faces southwest and is shaded most of afternoon; I don’t like the look of the panels on the front of the house; quotes from installers say productivity will be much lower; that makes sense but want to see if there are any other options in your opinion.

    1. Hi Sheila,

      Thanks for the comment. You can read about the viability of solar on a south-facing roof in this article. Long story short, yes you can install solar on a south-facing roof (or north-facing roof if you’re in the northern hemisphere – which it looks like you may be). If the shading isn’t really, really bad, you might be able to deal with the issue with microinverters/power optimisers.

      Best of luck with your system!

  3. I would be grateful for any thoughts/suggestions on the direction to face solar panels. We are looking at installing a 5kW system (LG Neon 2 panels and Fornius inverter) on a double storey house and had initially thought of splitting the panels between our north, east and west facing roofs so that we got production over most of the day (8 panels north, 4 east and 4 west). Feed in tariff is so low, we want to maximise self use. However, the installer says the inverter they recommend can only handle 2 array strings and that ideally each string should be on one roof direction. Now thinking of putting half the panels on the north facing roof (actually is 10 degrees west of true north), but we are not sure which roof to put the other half on. Our East roof faces 10 degrees north of true east, but we use more power in the later afternoon evening when all of us are home. The west roof faces 10 degrees south of true west, but the sun is lower in the sky apart from the middle of summer. We also have a single storey extension out the back (north facing roof) and a 5m x 6m flat roof over the deck. None of the roofs are shaded. Wondering if west is best or should we ask about having some of the panels mounted on the flat deck roof so they face north-west ?

    1. Hi Mark,

      If you haven’t already, you should consider getting proposals from a few different installation companies (you can get some indicative quotes here). Each installer you get a quote from should be willing to put in the time to show you modelled outcomes for each of the scenarios that you suggest – so that you have hard data to work off of instead of just speculation.

      Off the top of my head, I’d recommend going for the north-facing roof as a priority, and the west-facing roof as your secondary option – mainly for the extra solar production in the afternoon. But don’t take our word for it – as noted above, you’d do yourself a favour to get quotes from a few different installers – and as a reference you can also explore the numbers yourself using the PVWatts calculator.

      Hope this helps!

  5. We have increase in usage 150% last bill winter,3.2 kw system 16 panels north facing with 3 phase supply and single phase inverter, our dilemma adding 2.08 kw 8 panels to west or east side upgrading inverter to 3 phase to even out distribution ,or add separate 5kw 3 phase system east/west.

    1. Hi Peter,

      Your better option would most likely be to upgrade your inverter and add more panels, but we recommend that you speak to a few accredited solar designers/installers to get different opinions & quotes before you make your decision. Feel free to fill out the Quote Comparison Request form to the right of this page to see pricing & contact details from installers in your area.

  6. Dear sir,
    ! am in Bacchus Marsh Victoria.
    I have had a 2Kw system for sometime facing north. works a treat. But with most electricity usage in morning and evening, it would be advantageous to put panels on the east and west side as well. So I was thinking of upgrading to a 5Kw system, with say 6 panels on the east and 6 on the west side and the rest on the north side. Would this be able to run off one 5KW inverter? given that in morning or evening one side will produce a lot while the other very little.

    1. Hi Richard,

      First of all, I should note that you’ll probably not want to increase your system size if you’re currently receiving one of Victoria’s solar feed-in tariffs – increasing your system size could result in your rate being reduced if you’re on the Premium, Transitional or Standard FiT.

      If you’re not on one of these FiTs, however, your solar buyback rate is probably a pittance (6-8c/kWh), so you may as well expand your system if you think you can use all the energy it produces. Whether the inverter will be able to handle the additional panels will depend on its features – many inverters in that size range have dual-input Maximum Power Point Tracking (MPPT) functionality, which means you can put two solar panel arrays on different orientations and one won’t ‘drag down’ the output of the other.

      Hope this helps!

    1. Hi Terry,

      I’d need to know the specifics of your situation to work it out exactly, but you’re looking at a yield loss of about 15% annually if you face the panels west as opposed to north. You can play with the numbers yourself using the PVWatts calculator if you like.

  8. i have a roof that i will need to put 4 panels facing east am sun if i tilt them up to get some southern will that help

    1. Hi Hank,

      I assume you’re in the northern hemisphere because of the fact that you’re talking about facing the panels south (we are Australian so usually talk about north-facing panels being ideal). Equator-facing is usually the best orientation for fixed-array (i.e. no tracking) solar panels. If you face the panels east your panels will generate less energy over the course of the day than if they were facing north, but if you use more electricity during the morning hours this might make sense for you.

  9. With east (or west) facing panels the sun will be behind the roof for half the day. In winter when the sun is at an angle less than the pitch of the roof the panels will receive NO sunlight. In contrast, a north (southern hemisphere) facing roof gets sunshine from dawn to dusk.
    How can an east facing system produce anywhere near 80% of the energy of the same north facing system considering that when the sun is at the best angle for the panels it is probably far from its highest trajectory and have lower illuminance?
    I’m no expert, just trying to understand.

    1. Hi Andy,

      If the array faces east, the panels will receive more direct sunlight from earlier in the day, and will continue to generate power (albeit less power) for as long as the sky is bright. That’s why the efficiency only drops to around 80% as opposed to 50%. You can play with the numbers yourself using the PV Watts tool from the US Department of Energy’s National Renewable Energy Lab (you can pull up data for Australia as well as spots in the US).

      Hope this clarifies things!

  10. Hi

    Thanks, interesting site :) Hope it is still working.

    Everyone must be happy with their systems, as no comments for over a year ?

    I have a system INSTALLED with 16 panels East and 16 panels West.
    (no North facing roof) = 180W x 32 – efficiencies.

    Each 16 is going into a separate 2K5 inverter(2 inverters).

    The problem I am having, is the inverters keep rebooting.

    I have traced the fault to be the “initial” mains voltage.

    As I am in Perth. In WA our mains is 240V (optimum) but GOES up to 254 Volts (within specs).

    For the inverters to “export” current to grid, the inverter voltage has to be higher than the Grid (to create current flow) BUT as the output wattage increases the voltage goes over 260 Volts (often less than 2500 W), resulting in an inverter “booting”.
    This happens continuously from about 9:30 to about 15:00 and happens on either inverter.

    MORE houses in my area are getting Solar Panels, which has been increasing the mains Voltage over time, so is now always OVER 250Volts.

    The supplier says “it is NOT their problem” it is Western Power’s fault.

    As the Western Power Voltage (with Inverters turned off) is within their spec, how can it be their fault ?

    What can I do ?

    Thanks

    Graham
    P.S. Do some inverters STOP increasing their voltage when at maybe 259.9 Volts instead of booting ?

    1. Hi Graham,

      I’ve asked some of the industry’s exports on this topic and here’s what they’ve come back with:

      -From Trent of Zero Export Controls:

      The Delta 2k5 inverters mentioned below have an AC output window of 210V…..264V..

      Since this particular inverter does not have reactive power control … leading and lagging power factor, then there is little that can be done.
      I would suggest using an SMA or ABB inverter that has the reactive power control ability..

      -From Nigel Morris of Solar Business Services:

      It doesn’t say so, but it’s possible that its voltage rise in his sub line, rather than the mains??

      Seems unlikely to me that it would be a problem every day, unless he is in a really bad area or he has a specific issue.

      As an alternative to replacing your inverter, I would recommend that you get in touch with your inverter’s manufacturer to see if they can help you out with some more technical support about your situation.

  11. I live in Cairns and have had solar panels (8 giving 1.5Kw output placed in a 3,3,2 config.) since Feb 2010. My house is E/W facing with no obstructions or overhangs. I had complained many times that my panels seemed to be set too steep. I had them reduced end of last
    year by about 50% (guessing) but the output is no different. I produce on an optimum day ( i.e. sun all day) 6 kw hrs total and export an average 2 kw per day.
    Our latitude is 17 deg S. Am I getting the right value??
    Thanking you, George Laws

    1. Hi George,

      With regard to the tilt and orientation of your panels, in an ideal world all panels would face due north and be tilted to a degree a little less than the line of latitude. In Cairns the optimum tilt for north facing panels is 16 degrees. If you’re panels are either the East or West facing (or both) you can expect the production to drop to around 85%.

      The other reason you’re panels may not be producing what you expect may be a fault with the inverter or an issue with the wiring, the installer should be able to check both of these for you.

      Hope this helps

  12. Hi,
    I am in the process of getting Solar Panels installed on my roof. The front of my house faces north. The sales person suggested I install a 2.2kW system with 12 panels . The techs rocked up on my door step and informed me that they will not be able to fit 12 panels on the front roof (lack of roof space) and suggested that I split the panels- 6 facing west and 6 facing east. They have offered me a Dual tracking inverter.
    I am now a bit worried about the efficiency and have read on multiple sites that it is ideal to install the panels facing the north. The techs have assured that they done similar setups(east and west panels) for other customers and the result was good.
    I have been searching the web for reviews on a similar setup but have not been able to get a decent review
    Does anyone have any suggestion?
    I have clearly informed the installers that if the setup is not efficient in terms of power generation then I will not make the full payment and that they will need to relocate the panels.
    Any suggestions would be highly appreciated.
    Thank You

    Note: Not sure if I am posting this in the right area.

    1. Hi Nicholas,

      What the installer has proposed sounds like a good solution, what is concerning me is the number of panels they are selling you. If you are getting 2.2kW from 12 panels the panels would be around 180-190 watts each, which will cost you less but isn’t as efficient as some of the newer panels on the market which are between 220-250 watts.

      Some installers do have a clause within their contract that states they will relocate panels for free if they are not operating to their optimum capacity. If you would like a second opinion and a review of the market you can complete our FREE Solar Quote Comparison located to the right of the page. That way you’ll be able to ensure you got a good deal, have been advised correctly about the size of system best suited to your needs and, if not, have a selection of locally operating installers to choose from.

      Hope that helped and we look forward to assisting you in the future.

  13. Hi, my current usage per day is approx 40kw and I have had 18 x 200w panels installed on the west side of the roof with a 5kw inverter , the installer asked were I wanted the panels , and I said that you are the installers and should tell me, the installer went on the roof and came back and said he could either do the west or east, he suggested the east as there was only 1 % difference between the west and east on his “meter” and said that we would loose that 1 % due to the extra wiring needed to get to the inverter.Can you advise wether this is right. My east roof is 98 degrees east and 296 degrees west on my compass,hope that makes sense and look forward to your reply

    1. Hi Graeme,

      The preference is a north facing roof but there arguments about the benefits of placing panels on a west facing roof. If you’re roof runs directly through the east/west orientation there would be no real difference in the energy generated by the panels and the installer is correct about the energy loss through the additional wiring although it should be minimal.

      I am slightly concerned that they asked where you wanted them as opposed to doing the site survey and talking you through the best options, I would monitor the outage of your system and if it’s not performing ask the installer to come back and move the panels. Have a look at your contract, some installers have a clause that means they will move the panels free of charge if they are not producing to the optimum level because of their position.

      If you’ve not had the panels installed and want a second opinion you can complete our FREE Solar Quote Comparison, you’ll get quotes from up to 7 installers in your area.

      We look forward to hearing from you.

  14. I live in Cleveland just south of Brisbane. I have had a 4.7kw system installed but haven’t got exactly what I was quoted on. On my house there is no northern roof to install the panels, therefore, the quote was for all 24 panels to go on the western roof which is where all of the companies I got quotes from recommended. During installation, they found that all panels would not fit on the western roof and I would need to put some on the east. I was not very happy but I agreed verbally only to find that they actually installed half of the system on the eastern side. It is a split system so yes, it will work but from my research it won’t be as affective. I wasn’t happy with the whole outcome because at the end of the day, I haven’t received what was quoted on and I asked for a slight discount. The contractor then came up with electrical jargon saying it was actually better that the panels were on the east side. I disagree. What is your opinion? At this stage I haven’t paid the total balance which means I haven’t signed the paperwork which will ensure me the 44c tariff. Please advise.

    1. Hi Tony,

      I had a look on the system and it looks like you didn’t go through ourselves to get your solar quotes. If you did go through ourselves and used one of our installers please let us know and we may be able to speak to the installer on your behalf regarding the situation.

      It sounds like you are going to have a few issues, the first is that the 44¢ tariff ended in July, we don’t know of any way that you would be able to receive this if you didn’t submit the paperwork before the closing date. The second issue very much depends on your energy usage, what we recommended to our customers is that they install a system that closely matches their energy needs, as the State solar incentives (or feed-in tariffs) are so low there isn’t much incentive to feed back the grid. When the premium feed-in tariffs were still available, or we could ensure that customers would have the system installed and the paper work completed before the cut-off date, we recommended a larger system that would feed into the grid as the money the system made helped to pay it off much quicker.

      In either instance we would look at your roof space and work out what size of system you could accomodate, if the East side of your roof would generate an acceptable volume of energy we would advise installing there, but only if it would be an economically viable option. In the first instance we always look for the north facing roof, or, generally speaking, west in the second. If the East side of your roof faces due East and there is little to no shade it shouldn’t make a huge difference, your installer should have a ‘Performance Guarantee’ which means if your panels are significantly under performing they should come out and move them at no extra cost. It will be part of your contract.

      Without knowing what installer you used I can’t confirm, but all of our installers are Clean Energy Council accredited which gives our customers the knowledge that the job is being done to a certain standard. There are guidelines on the Clean Energy Councils website for consumers which may help you further.

      We hope you get this sorted out soon and can start enjoying the benefits of solar PV.

  15. Hi
    Live in a duplex on the Gold Coast so we have no choice as the postion of the panels-the roof faces predominately east and just a little south
    One company suggested racks to ensure they face north but this not our preferred option ($900 extra)
    Will it be okay if they face as is.
    Cheers

    1. Hi Peter,

      Without seeing the building I wouldn’t be able to comment, what we normally advise is that panels are faced north for maximum exposure and if that isn’t available on a west facing roof space. You may still get some light and generate some power if you have them installed ‘as is’, but the $900 extra cost for the racks to get them to face north may be worth the extra investment because of the extra energy you’ll generate and, therefore, extra money you’ll save on your energy bills.

      It doesn’t look like you went through ourselves in order to get a FREE Solar Quote Comparison. I’d recommend you fill this is in as in addition to getting a quote fr up to 7 installers who operate in your local area, you’ll be allocated your own personal Solar Broker who’ll be able to take you through the quote and help you deal with any issues you have up to, during and after installation. All our installers are Clean Energy Council accredited so you know you’re getting the job done properly. If you’d rather speak to one of our Brokers direct call 1300 78 72 73.

      We hope this helps.

  16. I am at Mango Hill-north of Brisbane. I ordered Origin 4.7Kw system. When they came to install, without a site inspection, 22 Sharp 215W Panels with Clenrgy SP50 Inverter, only 18 would fit on my Northside & I did not know that the panels could not be split between North & West without a Dual Tracking Inverter. When I called Origin, they said they do not install a Dual feed Inverter. So I was left to make a decision on the spot – “Should I put only 18 Panels on the Northside or put all 22 Panels on the West side?” I decided on all 22 on Westside. Did I make the right decision? What is the loss calculation between the 2 choices?
    Also I am not happy with the Clenergy Inverter display – it does not have a date entry & doesnot re-set daily to show peak Output/day. Is there anyway to improve output info?
    After a few years, if I decide to install panels on the Northside, is it possible to have 2 inverters connected to the grid?

    1. Hi Mathew,

      Thanks for the comments.

      I think you made the right decision to go with the 22 panels on the west side–generally you only lose up to 20% of the output of the system by going from north to west (depending on the angle of the roof). This is especially so if installing the system means you were able to meet the deadline for the 44c/kWh feed-in tariff, which is now closed to new applicants!

      For a rough comparison:

      a) Assuming an average 10% output loss due to undersized inverter and fewer panels:

      18 panels x 215W x 4 hours sun/day x 90% = 13.9kWh/day

      b) Assuming 20% output loss due to west-facing panels, but with the full array of panels:

      22 panels x 215W x 4 hours sun/day x 80% = 15kWh/day

      So option b) seems to be the better one, especially when you consider that the most expensive electricity rates are charged during late afternoon if you are on a ‘time of use’ electricity metre.

      About putting more inverters on the northern aspect of your house: If you’re currently receiving a Feed-in Tariff, adding a second inverter might result in the forfeiture of the eligibility for the FiT on the original system, so consider carefully.

      Best of luck with your system!

  17. Hi, we live in Brisbane and we are looking at getting a 5kw system with 27 panels (price $11500) on a due WEST facing roof. At this time of year, the roof starts to get sun at around 9.30 (on an acute angle of course) and the roof is in shade by about 4.20pm (we live on the eastern side of a hill). We did qualify for the 44c tariff and I am wondering, considering the info above, if you think it is a worthwhile investment and what do you think the return would be per quarter, just having trouble deciding if it is the right way to go or not. Cheers for your help, Paul

    1. Hi Paul,

      What capacity are the panels when totalled up? I presume they’re around 5kW?

      Also, do the times you’ve mentioned apply to both summer and winter?

      Give us a ring on 1300 78 72 73 if you’d like to speak with us further

      1. I think total capacity would be around 4.1kw because the “salesman” said you could add another 6 panels to the system later.

        The times I mentioned just apply to August, in Summer we would benefit from longer days.

        1. Hi Paul,

          You might want to consider looking into another installer. I don’t know what quality components they’re offering, but you can easily find a decent quality system for around that price–with panel capacity that roughly matches inverter capacity! We generally don’t recommend going with an ‘upgradable’ system (i.e. inverter bigger than panel array capacity), as they’re sometimes called, because when you eventually add on the extra panels you need to make sure you use the same exact products to make sure you’re getting the best out of the whole array. Additionally, it’s not good to mix older and newer panels–panels degrade slowly with time (perfectly normal) but you won’t get the best out of the new ones because their output will be ‘dragged down’ by the older ones.

          You can get a free comparison of quotes from installers in your area by filling out our Quote Comparison Request form and checking your inbox. We also provide advice if you get in touch with us (1300 78 72 73), and our services are 100% free to our customers.

  18. I have an existing 3kw system,installed 14months ago. If I want to install a new 2kw system to reach the maximum 5kw will i need to register again before July 9 to receive the 44c or am I covered by the existing contract. (Brisbane)

  19. Hi recently moved 6 x180w panels from west to due north and left 6x180w panels on the west side to try and maximise production.
    I have a 2kw orion system have i down the right thing?
    Thanks
    David

    1. Hi David,

      Generally speaking it makes more sense to keep all panels facing due north, as doing so results in greater overal solar power yield throughout the day. The only reasons you might put the panels on the west are 1) if you had no option to install on a north-facing roof, 2) if you had shading on your north-facing roof, or 3) if you were really keen on taking advantage of the sun as it goes down (some people might do this to insulate themselves against paying peak rates for electricity, but for the most part the efficiency losses mean that it’s not worthwhile). Do any of these options describe your motivations for the change?

      Whether you did the right thing also depends on whether your inverter has dual inputs for separate strings. I’ve conducted a quick search but have been unable to confirm this. If you have only one input, your system will suffer significant output losses through the day due to the fact that panels will not receiving an equivalent amount of solar irradiation–the output of the entire array is limited by the ‘weakest link’.

  20. G’day & great feedback on your website. I am getting a 5.5kw system with 30 panels installed on my house. i am getting 18 on the west facing roof and 12 on the east side. The west side has 5 degrees of north. Is this the best configuration or should I put all the panels on the west side? (yes I am getting an inverter with dual input). 2e are in maryborough qld.

    1. Hi Tim.

      Thanks for the comment. As long as your inverter is dual MPPT-capable (which it should be for a system of that size), it’s perfectly fine to split the array as you have indicated, but depending on what time of day you expect to use power most (and if there is a Solar Feed-in Tariff available where your house is located) it would probably be best to install more panels on the west side of the roof. There are 2 reasons for this: It does have a slightly more favourable aspect (slightly northwest if I understand you correctly), plus the above-mentioned advantage of more power production during peak times.

      Hope this has cleared things up for you a bit. Feel free to comment again if you have more questions.

  21. I’ve had 2 quotes for my 3KW system, one company suggested N-W side, the other N-E side. I don’t have straight N facing roof space. I live in Perth.

    To me N-W seems more sunny even in winter. I do prefer the company suggesting N-E, should I ask them to redesign to N-W? :)

    1. Hi Barbara,

      You live in an area with no government-sponsored Solar Feed-in Tariff, so the important thing for you is to ensure that you are using all the power that your solar system produces while it is being produced. It is worth more to you if you do this than if you allow it to be fed into the grid.

      So the main question is whether you are at home and using more power in the mornings or the afternoon. If you plan on using lots of electricity during the mornings, having an east-facing system will help you offset your bill. If you plan on being home in the afternoons, a west-facing array would be better. A west-facing array would also be good because it would enable you to avoid paying peak electricity rates, which are higher than off-peak morning rates.

      Hope this has been helpful.

  22. We are looking at upgrading our solar from 1Kw to 5Kw system but would need to split the pannels as we only have enough room for 1.5Kw on our Northern roof next to the solar hot water. Does having Western facing pannels running through the same inverter at the Northern facing pannels decrease the efficiency of the Northern Pannels or does the system work as every pannell for himself to do the best that he can when he can?

    1. Hi Teresa,

      Sorry for the delay in replying. While it is possible to add extra capacity to your existing solar system keep in mind that it may forfeit your eligibility for the states feed-in tariff, you’re best to check with the government website for more information. To our knowledge you will be able to receive the current feed-in tariff in your area for the new sized system.

      If you do decide to proceed you will need to purchase an extra inverter for the Western panels as they cannot run off the same inverter.

  23. Hi,
    I live in Melbourne and only have NE or SW orientation that would be suitable for 8 panels,could you tell me what direction would you recommend.

    1. Hi Steve,

      Thanks for the enquiry. NE would definitely be the preferred option over SW. South-facing roofs don’t get much sunlight in Australia. The above article is basically just trying to say that if you don’t have the option to put your panels on a north-facing roof, the next best option between east and west is generally west. South would not be considered a viable option by most installers.

  25. Dear Sir/Madam,

    We live in Townsville North Queensland and our house sits South North on the block, best roof position will be East or West both 25 degrees, we are looking at a 4Kw system no shading or trees at all so which side would be best. (East West is 90 / 270 degrees with a compass)

    1. Hi Chris,

      West is generally the next best option after north. For further advice, please get in touch with one of our brokers directly by calling us on 1300 78 72 73 or by filling out a Solar Quote Comparison request form. Our service is 100% free to our customers.

  26. For those of you in the tropics (Brisbane included) keep in mind that its not uncommon to have an afternoon thunderstorm (summer) on a regular basis. If not a thunderstorm then certainly a build up of clouds. Therfore, a North East facing system is always better.
    I speak from experience in my own system, plus the observation of many others on pvoutput.org.

    Hope this is useful.

  27. I remember when reading about solar panel technology that the efficiency of mono- and poly-crystalline panels drops off with temperature increase. Is this
    also a consideration when making the east vs west decision? I mean, usually the
    ambient temperature will be lower in the morning and higher in the
    afternoon, so the panels would be operating most efficiently in the
    morning while they are cooler. Is this an argument for putting them on
    the East side rather than the West (assuming all other considerations
    are equal – eg, that mornings aren’t more cloudy than afternoons)?

    1. Hi Jeremy,

      You’re right that temperature is an important consideration when deciding whether to place your panels on either your east- or west-facing roof. However, for the most part, it’s a bit of a coin toss in terms of efficiency loss due to overheating and the possibility of morning clouds. As a general rule, neither side will definitively have greater losses than the other.

      The real deciding factor is the fact that home energy use tends to be higher in the afternoon, and therefore you’re likely to get the most out of your panels if they are west-facing–whether you’re getting paid to feed solar power into the grid, or your household is consuming it directly. This is especially so if you are on a time-of-use (TOU) billing plan with peak, shoulder, and off-peak rates. Ensuring that customers’ solar systems output optimally might be the reason that Solar Switch only installs on roofs with northerly or westerly aspects.

      Hope you find this helpful!

Comments are closed.