SunPower Solar Panels: One of the best panels lots of money can buy

sunpower solar panels

SunPower make very good, very expensive panels.

SunPower make some of the best solar panels in existence. Or at least some of the best on this planet. Perhaps Spectrolab regularly shoots better ones into space to mars or somewhere, I don’t know. But if you want to buy something that is meant to go on a roof and not a space probe, then SunPower solar panels are hard to beat.

Now note that I did say some of the best and not some of the cheapest. If you haven’t worked out that the words cheap and best don’t normally go together, then I have a really low quality laptop held together with superglue and wooden rulers that I’d like to sell to you at a really high price.

SunPower Pricing

So let’s deal with the elephant in the room right now:  Sunpower solar panels’ prices. SunPower are one of about 30 panel brands that are called “Tier 1”. 1 Eighty percent of Tier 1 panels are made in China and are all sold in Australia at a very similar price per Watt. Examples include Trina, Jinko Solar, Risen, Renesola, JA Solar and Canadian Solar.

If you want to go up a notch in price, performance and durability, you are looking at what I call ‘Premium Tier 1’ brands. These include LG solar panels, Q-Cells, REC and Winaico. These generally sell for around 30% more than the regular Tier 1 brands.

All on its own at the top of the price list are SunPower solar panels, costing 75-100% more than a regular Tier 1 panel.

sunpower cost

SunPower Solar Panels Price Relative to other brands

But if you want Rolls-Royce quality, you have to pay for it, and on Friday I sat down to have a little chat with Chris O’Brien, the Managing Director of SunPower Australia.  I wanted to find out why people are prepared to almost pay twice as much for SunPower compared to a typical Chinese Tier 1 brand.

What The Hell Is SunPower?

SunPower is a US company that produces panels in the Philippines, presumably because they saw the people there badly needed a boost to their low wages.

The company was founded in 1985 by Richard Swanson, who first started investigating solar cells because he was fascinated with their use in space.  The company spent $6 million developing space solar cells, but they were not a success and I couldn’t find a single example of their solar cells being blasted into orbit or beyond.  I’m afraid Spectrolab pretty much has the space solar market stitched up.  But I think SunPower deserves credit for trying.  Personally, I wouldn’t compete against Spectrolab in anything, as they are clearly winner of the prize for having the company name that makes them sound most likely to attempt to kill James Bond.

James Bond: Everything he touches turns to excitement. And a little while later a rash

SpectroLab: They have a James Bond name and they beat SunPower in the solar space race.

Richard Swanson is also famous for Swanson’s Law, which states that for every doubling of production capability, the cost of solar panels fall by 20%. And while the price of solar panels have had their ups and mostly downs, his law has done fairly well.  So let’s all hope solar panels have a few more Swansons left in them.

SunPower’s Warranty Is The Best You Can Get

SunPower sell panels with a 25 year warranty. And that’s not just the performance warranty. I can buy cruddy solar panels from a company with an internet site that claims a photograph of an architect’s model is their factory and they will come with a 25 year performance warranty. While SunPower does have a 25 year performance warranty, I’m talking about their product warranty. That’s what’s important, because if your solar panel stops working, the performance warranty won’t cover that.  Only the product warranty does and SunPower Australia’s is 25 years, which is more than twice as long as the next best I am aware of.

SunPower’s failure rate is 27 in 1 million. That means only one panel in 37,000 is defective and needs to be replaced. So if you have a rooftop solar system of around 5 kilowatts with 15 panels, that means there is about one chance in 2,500 you will have a defective panel that needs to be returned. And those are damn good odds.

Did I say return a panel? Actually, there is absolutely no need to return it.  If you have a defective panel, SunPower will send someone to come and replace it.  Now that is good service.  And presumably they will take the old panel away and perform an autopsy to determine why it died so young and take steps to try to ensure it never happens again.

How Do They Offer Twice The Warranty Of Anyone Else?

Thermal expansion is a major cause of solar panel failure.  It results from temperature changes causing different materials to expand and contract at varying rates and puts strain on joins between different materials and can cause cracks to form in the thin metal wires that conduct electricity.  Once those wires break and stop the flow of current they can form a hot spot that gradually burns through the protective encapsulate that covers it, which can lead to corrosion and the failure of the entire panel.

SunPower claim to have completely eliminated thermal expansion as a cause of failure, for at least the first 25 years of their panel’s life.

They have done this by making the wires that collect electricity a fine patterned mesh on the back of the cell, which resembles a printed circuit board.  And this arrangement is apparently great at distributing stress caused by expansion and helps keep it together.

They have also greatly improved the survivability of connections between solar cells by having more of them and designing them so they suffer less stress from thermal expansion.

The panels also have a thin copper backing. Copper is a soft, ductile metal useful for avoiding damage from thermal expansion and it is also excellent for resisting corrosion. Unfortunately, copper is expensive, so perhaps they could benefit from using a different material. Looking up the periodic table, as I do at regular intervals, I see that elements with properties similar to copper are silver, gold, and something called roentgenium which decays so fast it has severe trouble lasting 25 minutes let alone 25 years. So maybe copper is a good choice.

sunpower solar panels' cell structure

SunPower cells have a copper plate on the bottom and a light trapping surface on the top.

Interestingly one of SunPower’s competitors in the premium solar panel market, Q-Cells are working on a cell design (codename: Q.ANTUM) that appears to be ‘inspired’ by SunPower but uses aluminium instead of copper, and has the reflector layer under the silicon:

q-cells q.antum cell

Q-Cells appear to be moving to a Sunpower style back contact, but they have chosen aluminium.

Aluminium is much cheaper than copper – so it will be interesting to see how the final Q-Cells Q.antum panels compare in performance, durability and price. Watch this space I’ll let you know as soon as I can get more information.

SunPower Panels Produce More Electricity Per Watt Than Most

SunPower panels are extremely reliable, but in addition, they claim to produce more energy over the course of their lifespan than many other panels. They achieve this in several ways.

  • They have positive tolerance which means the panels always produce at least as much power or more as their rating when they are new.  Never any of this plus or minus business.
  • They have no wires on the surface of the cell to block sunlight.
  • The panels are better at handling shade than standard panels.
  • They operate at a lower temperature which improves their performance.
  • They degrade more slowly than other panels.

Positive Tolerance

Solar panels vary in their output. No manufacturing process is so precise it can make perfectly identical panels.  Not even SunPower can achieve that.  But if you buy a 345 watt SunPower panel, you will be getting a panel that produces 345 watts plus 0 to 5%. That is, 345 watts is the absolute minimum. So any variation in output will end up favoring you.

Positive tolerance, where there is no downside, is not uncommon among high quality panels, but there are still many that have their tolerance as plus or minus a certain percentage. One of these panels could produce more than its rating, but it is just as likely to produce less. And then there are the dodgy panels that say they have positive tolerance but lie and their actual output can be all over the place.

Nothing Up Top

The surface of SunPower cells are completely nude. There is nothing there to block sunlight from hitting silicon. Many other manufacturers, but certainly not all, place a grid of fine, flat wires on top called the busbar to collect electricity, while on SunPower cells all the wires all go underneath. The difference between the two types looks like this:

a conventional poly crystalline cell and a cell used in sunpower solar panels

The difference between a solar cell with wires on top and a topless one. Yes, I broke the cell on the left. It’s not my fault I have eight thumbs and two fingers. I also smudged the one on the right with my thumbs.

Putting wires on top is easier to do and saves money, and there is nothing wrong with saving money, but from a purely energy efficiency point of view it’s a really bad design choice. It makes as much sense as if the vessels that supply blood to the light sensitive cells in our eyes passed in front of the retina instead of behind it. Wait a minute, that actually is how our eyes work. I think I have just said that SunPower is a better designer than God.

Shading caused by wires on top is worse when sunlight is striking it at a shallow angle, so for north facing systems SunPower panels will tend to tend to perform better in the early morning and late afternoon than panels that aren’t topless.

SunPower Solar Panels & Shade

Solar panels don’t like shade. The obvious problem is less sunlight energy hits the panel and no amount of design ingenuity can get around that. But there is the bigger problem that shading one small part of a panel can cause the output of the entire panel to fall, and if multiple panels are all connected to one inverter, as they usually are, one shaded panel can bring down the output of the entire string of panels.

This problem is reduced through the use of diodes which typically divide the panel into three, so if bird poop lands on one section the diodes can bypass that part and only cut the panel’s output by a third.  SunPower doesn’t divide panels into three, they have diodes on every single solar cell in the panel. And they have the advantage of not using physical diodes. So I guess this means they must be using some kind of spiritual diode.

This is important because physical diodes have a limited lifespan. While there are plenty of diodes in the world that have a Mean Time To Failure of 10,000 hours or more, the ones in many cheaper solar panels can be shot after 1,000 hours of use. So if a panel is shaded for three hours a day, its diodes could be useless after one year. In fact, some cheap and nasty panels can have their diodes shot when they are installed.  And this is something people won’t know unless they test them, and someone installing shonky panels isn’t likely to, (a) bother to test them, or, (b) tell you they got a bad result even if they did test them.

Check Out The Temperature Coefficient! These Are Some Cool Panels

The hotter silicon PV gets, the less electricity it will produce. That’s just the nature of the beast. It’s not like paper where if you get it up to Fahrenheit 451 it will suddenly give off a lot energy by bursting into flame. Or rather, Fahrenheit 842, as paper’s flashpoint is actually 451 degrees Celsius.2  It appears Ray Bradbury didn’t even bother to check the internet when he wrote Fahrenheit 451 back in 1953. What a lazy hack.

But highly efficient solar cells have a virtuous circle going where the more sunlight they convert into electrical energy, the less waste heat is left over to make the panels hotter. This is the opposite of a vicious circle, which is like Pac-Man when he gets drunk after a hard day of eating dots.

As a result of this, and also because the copper backing is also good at whisking heat away from the cells, these panels can run up to three degrees cooler than a run-of-the-mill panel, which results in higher efficiency.

Note this effect won’t result in extra electrical production above its rating. It is included when the panel’s rating is determined, but it will cause them to degrade at a slower rate, because the lower the temperature the slower materials decay.

SunPower panels vary in their ability to resist the effects of heat.  Typical panels will have their output reduced by about 0.4% for each degree rise in temperature.  The 20% efficient SunPower E series panels will have their performance reduced by 0.38%, which is okay.  And the 21% efficient SunPower X series panels will have their output reduced by about 0.3%, which is quite good.

SunPower Panels Degrade Slowly

Because SunPower panels are so good at keeping it together and not suffering from the effects of thermal expansion and because they are cooler than most panels, they degrade very slowly and so the fall in their output over time is very gradual.

Their warranty covers a 0.4% decline in output per year. So if you buy a 345 watt panel from SunPower Australia after 10 years it will still produce over 331 watts or they will replace it.  But the warranty is always going to be greater than the average actual decline, or it will be for any company that wants to stay in business, and I have been told the real world degradation of actual panels on roofs and in solar farms is 0.12%, which is excellent. So after 10 years you can expect your 345 watt SunPower panel to still be producing around 341 watts.

Who Should Buy SunPower Panels?

Unfortunately, SunPower panels are not cheap. They are roughly twice as expensive as conventional panels. But that’s just the way things are. If you want quality, you have to pay for it. And taking the long term view, if they produce 20% more electricity over 25 years then they are worth 20% more. And because SunPower will send someone to replace any panel that fails within its 25 years product warranty, that’s worth money too, as well as peace of mind. And if you take a very long term view, I feel confident there will still be plenty of SunPower panels continuing to operate after 50 years of use.

I think there are three basic types of people who would be interested in panels from SunPower Australia:

(1) People who value having the best technology available:  If you don’t care about paying more to get the most advanced panels and you want to aid technological progress by rewarding manufacturers who make the best products, then these panels are for you.

(2) People who value reliability:  If you want a rooftop solar system you can just, “fire and forget” and be extremely confident that you won’t have any problems with your panels for at least quarter of a century, then these panels are for you.

(3) People who are snobs.

There are plenty of people who will fit into the first two categories of wanting the best technology or an extremely reliable system. Our SunPower reviews give lots of examples of happy Australian customers who fit these 2 categories.

And there are also plenty of people who will fit into the third category. And if you are a snob that doesn’t know a damn thing about solar panels, but just know that you want the most expensive, that’s fine! There’s nothing wrong with being a snob! Or at least, that’s what my friend Gina told me on her yacht this weekend when we were spearfishing for poor people.

Future Developments

The E series which is about 20% efficient is currently available from SunPower Australia, as is the X series 345 watt panel, which is 21.5% efficient. And they will have a new type of panel which has lower efficiency, but is lower in cost while having the same utterly impressive 25 year product warranty, available at the end of 2016.

And I will tell you all about those panels as soon as they are released. Promise.


  1.  Tier 1 is not a direct measure of quality. It is primarily based on whether the banks trust the brands enough to make large loans to solar developers who want to use the brands. But in my opinion, buying Tier 1 is the best way to reduce the risk of buying a crappy brand.
  2. As Tom has pointed out in the comments, Ray Bradbury was pretty much correct when he gave Fahrenheit 451 as the flash point of paper.  The 450 Celsius figure I found on the internet is actually an outlier.  So Ray Bradbury back in 1953 with no internet was right and I was wrong.
About Ronald Brakels

Joining SolarQuotes in 2015, Ronald has a knack for reading those tediously long documents put out by solar manufacturers and translating their contents into something consumers might find interesting. Master of heavily researched deep-dive blog posts, his relentless consumer advocacy has ruffled more than a few manufacturer's feathers over the years. Read Ronald's full bio.


  1. G’day Ron, many thanks for a very informative article. Whilst I had some appreciation of the quality of Sunpower panels and their cost, I did not know about the finer detail surrounding cell interconnection and panel construction.

    In regards to aluminum back contacts, well I would caution against its use because Telstra used aluminum telephone trunk wiring back in the 1970s to alleviate the then cost if copper, but 30 years later, under a major Y2K remediation project I was involved with, all that wiring had to be replaced because it had become severely oxidized and brittle, thereby reducing its conductivity and serviceably considerably.

    Again, many thanks!

    • Ronald Brakels says

      Thanks for the kind words, Peter, and thanks for the insight into what happens to aluminium wiring after 30 years. Aluminium does seem to be the poor man’s copper, as whenever the price gap between them grows it is substituted for it, with varying degrees of success.

      But copper prices have fallen to a 7 year low, which will reduce attempts to replace it with aluminium and help reduce SunPower’s costs. And it will also shave a little off the cost of wind turbines and electric cars.

  2. Nice piece.

    QCELLS Q.ANTAUMs are already on sale in Australia, the Q.PLUS range.

  3. Tom Martin says

    Thanks for interesting article. It appears that the Panasonic 325w HIT panel is quite comparable in regards to specs but significantly cheaper. What do you think of it compared to the sunpower?

    • Ronald Brakels says

      Hi Tom, I haven’t had anything to do with Panasonic 325w HIT panels myself, but everything I have heard is good. However, they are very rare in Australia and may be hard to find. What impresses me is I just found out they offer a 15 year product warranty, which as far as I know is the second best in the industry.

      • Hi Tom
        Great article and very informative. I’m sold on sun power panels. Which inverter would you recommend to use with my sun power panels

        • Ronald Brakels says

          Hi Ann

          If you want to get the maximum possible output from your panels I suggest either microinverters such as those made by Enphase or a high quality string inverter with optimisers. If your budget doesn’t stretch that far I’d recommend just a reliable inverter such as a Fronius.

          Our Solar 101 Guide shows all the inverters we can recommend in a graphic and they are arranged from left to right in order of expense:

  4. Tom Conner says

    Great Article Ronald, it furthers my resolve to choose Sunpower panels for the zero energy residence I am currently building. I also really appreciate your humor throughout.

    PS – I think you were joking about Ray Bradbury being incorrect about the flashpoint of paper…? But it did compel me to look it up and confirm that he was pretty darn close:

  5. Tom Conner says

    No worries Ronald, keep up the excellent and funny writing.

  6. MatthewCooper says

    Out of curiosity, where would Yingli panles go in the scheme of things?
    would be good to see a list of the tier 1 break up (standard vs premium)

    • Ronald Brakels says

      Yingli makes tier one panels with a 10 year product warranty, which is standard. As for tier one panels that could be considered to be premium, I can think of three off the top of my head that have product warranties longer than the standard 10 years. Hanwa Q Cells Q.ANTUM line of solar panels have 12 years, Panasonic has 15, and SunPower is the champion of warranties with their product warranty equal to their performance warranty of 25 years.

    • From Chinese perspective, Yingli is like IBM of solar panel company. It is having reputation for deep ties with Government. You choose Yingli when you want to feel secure that company will be around forever.

      Quality is always assure. State Key PV laboratory is located in Yingli HQ Baoding and they make n-type.

  7. Solastic says

    I was given a few quotes to start up with solar panels. One supplied Seraphim 260W panels and the other SAID they supplied tier 1 Australian made Matrix solar panels. What is your opinion on these?

    • Finn Peacock says

      Seraphim are a reasonable Tier 1 panel.

      I don’t know about Matrix – it’s a pretty obscure brand – they are not Tier 1 on any list I’ve ever seen.

  8. Which would you choose Sunpower or LG? LG appear to be newer technology but Sunpower good write up too!

    • Hi I am also interested on which panels would be a better choice:

      Sunpower E20 327W or LG Neon2 330W ?

      • Ronald Brakels says

        They are both very good panels. SunPower provides a 25 year product warranty while the LG NeON 2 has 12 years. (Looking at its datasheet, the LG NeON 2 has a maximum of 320 watts.) Their efficiencies are similar with the SunPower E20 at around 20% and the 320 LG NeON 2 at 20.8%.

        The good news is you are extremely unlikely to need to use the warranty for either.

  9. david warren says

    Hi Ronald. I just checked the warranty on sunpower E20 panels and the product warranty is only 10 years not 25 years.

    • Ronald Brakels says

      I suspect the information you have isn’t correct, David. The Australian SunPower site says their E20 panels have a 25 year warranty and it is clearly stated on their datasheets. I’d be very surprised if it’s not actually 25 years.

      • David Warren says

        Ronald. I am holding in my hand the data sheet for sunpower E20/333 and E20/327 solar panels.
        under the warranty and certifications it clearly states ,and I quote:-
        warranties. ’25 year limited power warranty’
        ’10 year limited product warranty;

      • David Warren says

        Hi Ronald. My apologies to you. I am now holding another sun power sheet which confirms what you say about sun power panels. 25 year power and product warranties. perhaps the original was one of those items that gets left floating in cyber space. It has a 2011 date in very fine print in the lower left hand corner.

  10. Two minor points: The grid of silver “wires” (which are lines screen printed onto the cells) on typical solar cells is made up of wide bus bars and narrow fingers. Not all the silver lines are bus bars, just the wide ones.

    You are confusing flashpoint with auto-ignition point. Bradbury never said the flashpoint of book paper was 451F. He was referring to the auto-ignition point. The flashpoint of something is when it is hot enough to produce enough vapors to support combustion from an external source. The auto-ignition point is when a material spontaneously bursts into flame. Whether 451F is correct for the auto-ignition point of book paper, that is a whole different debate, and will depend very much on what precisely you mean by book paper (and I don’t want to get into that debate!).

    Another advantage that Sunpower cells have over mass-market cells is that they are n-type (phosphorus doped in their bases) rather than p-type (boron doped in their bases), which means they don’t suffer from light-induced degradation when put into the field. LID (light-induced degradation) is caused by B-O defects which are activated by sunlight. P-type cell manufacturers have started taking steps to reduce LID, but no one knows if these fixes will last for the lifetime of the panel in the field.

  11. Horatio Gonzalez says

    You had me until a heading like “More electricity per watt”. That’s like a car that travels more distance per kilometer? Watt (What) the?

  12. Hi Ronald,

    Thanks for a great article.

    I’ve got quotes for a ~ 6KW solar array using different panel manufacturers (incl a 5kw inverter and installation etc). They look like this in terms of out of pocket costs:

    ET = $7990
    Canadian Solar = $8280
    Flex = $7990.
    REC = $8490
    Sunpower X Series = $11234.

    Based on your article, I was expecting the Sunpower option to be substantially more than the roughly $3000 premium over the others. Are the Sunpower X panels true in terms of the points in your write-up, or are these a lower-spec panel that aren’t “that much” better than the standard tier one manufactured panels?

    Thanks in advance for any advice you can give.

    • Finn Peacock says

      Hi Joseph,

      Finn here. Yes X Series panels are the most efficient SUnpower panels and have the Maxeon cells and 25 year manufacturers warranty – so all the benefits Ronald writes about. They are top notch panels.

      Hope That Helps,


    • Andrew Krantz says

      Hi Joseph
      I got a quote for a similar sized system but it was $13,800 foe the e series.
      Your quote was much better. Can you tell me the company and we’re you happy..
      Ps did they incl optimisers ?

  13. Does the Sunpower panel have less need of or benefit from individual micro inverters?

    • Ronald Brakels says

      A SunPower panel will be less affected by shade on an individual panel, such as from a leaf or a bird dropping, than perhaps any other panel out there. So it might have an 11% loss rather than a 33% loss. But if one panels in a string suffers a loss it will still drag down the performance of other panels on that string. So while there is less need for individual microinverters (or DC optimizers) they can still help in getting the most electric energy possible from a system.

  14. Graham Lewis says

    Hi Biased judge !

    Why do you say these are the BEST, with best guarantee but on this same website, it says SolarWatts is the BEST !

    Which is the LIE ?

    What is the point or reading conflicting information ? ? ? ? ?

    WE EXPECT better !

    • Ronald Brakels says

      People assume that time is a strict progression of cause to effect, but *actually* from a non-linear, non-subjective viewpoint – it’s more like a big ball of wibbly wobbly… time-y wimey… stuff.

      But if you’ll bear with me and assume that time progresses in a linear fashion from the past to the present then it will all become clear.

  15. Hi Andrew.

    I bought from Energy Matters. I’m in Victoria in case that matters. The price was for the panels plus a Fronius inverter, and installation. I didn’t have micro inverters installed.

    The sales and installation process was pretty good. But I’d have to say after that it wasn’t great. It was installed & inspected in September, and I’m still waiting for my retailer to be updated with the fact that I’ve had solar installed…so I’m not being paid for what I pump back into the grid. My retailer assures me that when the paperwork is sorted I’ll get paid for everything that my system has produced, because the meter started at zero. But still. I’d go with them again, but be prepared to keep hassling them after the install.
    Good luck.

  16. Andrew Krantz says


  17. Paddy Kearney says

    Thanks for the article Ronald. I am bugging my salesman with too many questions after sitting on my hands for a few months after a blow back event on our new roof!
    I am in SEQ and am down to Hanwha Q-Cell G4 300 w vs Sunpower 327 w panels.
    The Scottish side of me is pushing me to one side, but keen for some advice.

    • Ronald Brakels says

      Hello Paddy

      They are both good panels and unlikely to have problems. The SunPower ones are better at resisting the effects of shade but if your roof doesn’t have shade it won’t make much of a difference. The Hanwha panels have a 12 year product warranty while SunPower has a 25 year full replacement warranty. So I guess the decision comes down to how much value you place on the peace of mind that comes with SunPower’s superior warranty.

  18. Malcolm Raward says

    We have a roof orientation of 209 degrees, i.e. south, plus a 10 to 13 degree pitch to the south and an inability to tilt any panels. It seems that the Sunpower panel would be best for this situation. Any comments?

    • Ronald Brakels says

      I don’t know where you are located, but the good news is in Sydney at least panels facing that direction will only produce around 18% less energy over a year than if they had been facing directly north. The low tilt of the roof helps.

      SunPower is a very good panel, but won’t have any additional advantages over other panels in that orientation.

  19. Malcolm Raward says

    Location is Wynnum Qld

    • Ronald Brakels says

      The PVWatts site:

      Tells me that your panels will produce 87% of the energy they would if they were facing directly north. Output will be low in winter and high in summer with June production nearly only one-third that of December.

  20. Malcolm Raward says

    Thank you for your comments

  21. Shannon Dean says

    We live in Southern California and signed a lease with SunPower through a local installation company. We liked our installation company, but since installation 3 years ago, our system has been down 5-6 times (and even though the system is connected to the internet it does NOT notify you or them when it is down, so several times it had already been down for a week when my husband happened to be in the garage and notice there was an error message). It has been down over 10% of the time that it has been on our roof. While initially our local company/installation company handled our repairs, it has broken so many times (including replacing the inverter twice and replacing all the panels), that they say they can no longer handle our repairs and we are now being referred to the parent company, SunPower.

    Unfortunately, SunPower is unresponsive and has zero customer service. Our system most recently has been down for over 30 days, we have called multiple times and been told we are on their “high priority list.” Heaven help those not on the high priority list, because even that took 3 weeks to get a team out to even look at it. It has been 10 days since then and we still had not heard anything from SunPower. We are currently paying $160/month for a solar system that doesn’t work, on top of exorbitant SDG&E prices because our solar system is down in the middle of summer. We finally got a call back after multiple calls and emails over 10 days, just to be told they still haven’t received a report from the technicians, they don’t know what the problem is and they don’t have an ETA to fix it. They said “maybe” 2-4 weeks to finalize the report and determine the issue and then they can start planning a repair – this would mean our system will be down for 6-8 weeks by the time they even TRY to fix it.

    The lease provides a guarantee that SunPower will reimburse for any underproduction at the end of the year. It sounded like a great guarantee when we signed the lease. Here’s the catch: they reimburse at the lowest cost of electricity (tier 1 currently $0.14 per kW) and when your solar panels are not working or are significantly underproducing the issue is not the tier 1 charges, but the tier 3 charges (currently $0.55 per kW). With this summer having heat in the 100s and our panels out we have had two $500-$1000 electric bills that would have been significantly lower had our panels been producing and the charges had stayed in tier 1 and tier 2 levels. The $200-300 we will get in exchange at tier 1 rates does not really make up for the underproduction. SunPower should install products that properly work and maintain them so they do not need to utilize the guarantee or should reimburse at the tier 3 levels.

    I do not recommend signing a lease with SunPower. They do not stand behind their product, they refuse to make repairs on the system we are paying to lease. Find a different solar leasing company that stands behind their product.

    UPDATE 9/19/18: They finally fixed our system – it was down for almost 2 months before they fixed it. Given the number of breakdowns, two inverter replacements and replacement of all the panels, we requested a provision added to the lease regarding expectations on timeline for repairs and possible termination of lease if they do not meet these expectations (not an unreasonable request given our experience with them). They refused stating “there is no provision in your lease to terminate due to equipment failure…SunPower will not provide any further consideration relative to termination of your lease” So just FYI thats how much they stand behind their products.

    • Ronald Brakels says

      Sorry to hear about your unfortunate experiences. While SunPower has trialed it in Australia, residential solar leasing is almost non-existent here.

  22. David warren says

    Does this mean that we in aus who have purchased these panels will have a similar problem if anything goes wrong? I have recently had 20/327 watt panels installed because I believed in their claim that they would come and remove the panels and replace them if they became faulty as well as their 25 year performance and structural warranty. Time will tell.

  23. Thanks for your informative post Ronald. I really enjoy your writing style. I’ve just been quoted for panels from the Sunpower P Series. I noticed your post mentions the E and X series are very good, do you know if the P Series is similar in quality?

  24. Hi Ronald

    Great site. Am looking at a 5kW systems, and ne quote was for SunPower panels but a much cheaper on recommended ETsolar – elite Poly at 17.2% efficiency. Any tips on that option? Art

    • Ronald Brakels says

      Hi Art

      Sunpower panels are high quality with a 25 year product warranty while ET Solar panels are much cheaper. ET Solar is not currently a panel we recommend. You can see a graphic of panels we currently recommend in our solar 101 guide arranged from lower cost to more expensive:

      Generally speaking, the more expensive panels are higher quality. If you wish to see the details of panels you can find them on our solar panel comparison table:

      • Thanks Ronald, so I am off and running. Armed with 101, all the questions and a deep understanding of how much you guys use humour, I am getting quotes. I have a horrible feeling getting quotes will be easier than making a decision. So, seeking an Origin quote to see what FIT s apply. Hopefully not a real fit when I get the quote. Thanks to you and Finn. Will post as I travel along the path. art

        • Ronald Brakels says

          Glad to help. If you have any questions about your quotes, feel free to ask. Origin will offer a higher than usual feed-in tariff for 12 months when you buy a system from them, but because of the limited time it’s not worth a whole lot more than their other feed-in tariffs.

  25. Ian Compton says

    Just brought a 6.4 kwatt system from Sunpower. 25 years warranty which is great. Just over $10000. For the lot.
    Very happy with the article and put me in no doubt what to get. A little bit more to pay but I should save my costs pretty quickly. Thanks Ron

    • David warren says

      I’ve 18 of of those sun sucking SunPower E327 bad boys on the roof. Over the moon with their performance. They charge my 2/6.5 kWh LG batteries within a few hours depending on night usage and season, and the rest to the grid

      • Andrew Krantz says

        I don’t suppose you are based in melbourne as I’m looking to do a similar setup and you seem happy. Did you choose Fronius and use optimisers

        • Ian Compton says

          No we are in Sydney. I have ordered a fronius without optimisers.
          We have no shade or trees around and we are facing north. So we are luckly at the moment.

        • Ian Compton says

          No we live in Sydney. Yes i went with a fronius inverter . No I didn’t get optimisers didn’t need them where I lived. No trees no shade around and house facing north which is great for me

      • Ian Compton says

        Wow . I very excited about that news . We should be up and running in 2 weeks time.

  26. Hi Ron, getting there with quotes (including one from your recommendation). On Panels, in a 4kW setup, any thoughts on LONGI 310 LR6-60PE versus AllMax Plus 305? BTW I am going for a Fronius inverter….seems worth the investment. Art

    • Ronald Brakels says

      The Longi and Trina AllMax panels are fairly similar. Both have a 10 year product warranty. They also have a 25 year performance warranty with the Longi promising less degradation over time. Their efficiency loss due to heat is basically the same with the Longi doing just a smidgen better. Fronius inverters have a good reputation so that’s probably a wise choice.

  27. Is the SunPower X21-345 better quality than E20-327?
    Where can I check dateline of latest releases?

    • Ronald Brakels says

      Hi Max

      The Sunpower X and E series have the same warranty so I expect the quality to be around the same. Presumably the SunPower Australia site will have the most up to date information.

  28. Hi Ron.
    You seem to be quiet experienced in this industry. we in pakistan are working on solar power projects on commercial and residential level. recently we imported sunpower E series 327W, around 120KW, we are now planning to go with Enphase micro inverter IQ 7x, do u think we will get the best output from this system? we want to achieve the best result so we have decided to go with this option , how do u compare micro inverter vs string inverter results?
    we have used string inverters but never used micro yet. it would be first time.

  29. Cindy Durant says

    Interesting article and good sense of humour in your writing Ronald. I have lived off grid since 1987. We have had several system overhauls in that time. With the prices of solar panels going down so much in the time I have relied on them I am about to again redo/upgrade our system. It might be a two stage project as we can afford it. I am currently looking at LG Neon 2 panels. I have received one quote whew the installer wants to use REC Twin Peak 2 panels. Now I am reading your article I will need to research more on the SunPower options. I want the best because I would love to get another 20 years from our panels at least. I am so concerned about the mass consumerism and new issues in Australia about used & discarded solar panels…people usually look at price before quality when it comes to purchasing solar unfortunately. I am a user that completely depends on my system and getting the best is very important. I would love your thoughts on the other panel options I have mentioned. Thanks so much. Cindy

    • Ronald Brakels says

      REC panels are good quality and have a product warranty of 20 years. That’s not as good as LG or SunPower’s 25 years, but they have the advantage of not being as expensive. If you are deciding between SunPower or LG I’ll let you know SunPower’s current financial situation is not nearly as good as LG’s but even if they go bust and no longer around to support their warranties the panels should be very unlikely to fail so hopefully you would never need to use the warranty anyway.

      • Cindy Durant says

        Thanks Ron. I will keep that in mind. I was told that SunPower is now making some of their panels in china and that the quality is not nearly as good. What are your thoughts on this?

        • Ronald Brakels says

          Their Chinese made panels have the same warranty as their Philippine made ones, which is a good sign. These are their lower cost and lower efficiency P-series. I presume they’ll be very reliable, but they haven’t been around long enough to certain.

  30. Robert Pawley says

    Solar panel quoter using REC say I should not but a hybrid ready inverter as newer batteries may nit be compatible.


    • Ronald Brakels says

      Hi Robert

      Unless you want to get batteries very soon I say it’s best not to get a hybrid inverter. If you are waiting for home batteries to pay for themselves that might take several years. As it is a rapidly changing field there’s an excellent chance the hybrid inverter you install now won’t be compatible with the batteries you will want to get in the future. You can get battery systems that work independently of your solar inverter and so it won’t matter what kind of inverter you install now.

  31. Alonso Herrera says

    I am trying to install solar panels in my house and I decided to use sunpower after all my research, but after being quoted on the Series A 327W – AC i found the new panel came out of Series A 400W, i asked them to quote me on that and their quote is 19% higher on the price even thought the A 327 Ac need 46 panels and the A 400 Need 38 Panels
    That does not make sense, I don’t know any company who developed better technology to reduce the numbers of panels and became much more expensive. That does not make sense at all. Please can somebody help me to understand If i am being taking for a ride by the contractor

    • Ronald Brakels says

      I’m afraid SunPower is a premium product and so they charge premium prices. Their latest and greatest panels are priced like luxury goods to get money from loaded people who want the best. If you wait the price per watt on their 400 watt panels will come down, but you may not want to wait that long. If you have plenty of room on your roof I would say don’t worry about it and go with the lower cost panels.

  32. JOHN W BOTTOMS says

    A bit less than two years ago I bought six residential sized panels for use on a boat. These panels did not have the SunPower label, but used factory Maxeon cells. Does SunPower still supply their cells in a more budget friendly panel which could be purchased directly by the consumer vs. only by an installer? I seem to have misplaced this purchase info! Thanks

    • Ronald Brakels says

      Hi John

      SunPower make their own flexible panels and looking online they seem reasonably priced compared to similar wattage flexible panels that don’t have their reputation. With just a quick look, I couldn’t see any other brands using maxeon panels, but there could be available. Earche also make flexible panels and we write about an installation using them recently, but they don’t use maxeon cells:

      You can purchase flexible panels online and have them delivered to you. If you want the extra peace of mind of a face to face transaction you can check camping/caravan/boating places to see if they supply them.

  33. These 400 W Sunpower panels would seem ideal for a low roof area I’m considering for Solar. Rather expensive but I only have what I have.
    The 25 year warranty is fantastic.
    I’m thinking, however, what might change within the next 25 years or even 10 years? Will newer technology possibly increase output and might an increased take-up reduce costs? Might it be reasonable to perhaps think of replacing panels in 15 years?

  34. Hola Ronald

    Quisiera saber de dónde tomaste el dato “La tasa de falla de SunPower es de 27 en 1 millón”.


    Saludos desde España

    • Ronald Brakels says

      Este artículo fue escrito hace 4 años, pero estoy seguro de que habría obtenido esa cifra directamente de SunPower Australia.

  35. Hi Ron

    What is your view on Hyundai Panels, they also offer 25 year product and performance warranty and claimed to be Tier1.

    I do not have an issue with the shading at my place. What do you think?

    • Ronald Brakels says

      Hyundai panels are ones we can recommend. If you check out our Solar 101 Guide you can see they are included in our graphic of recommended panels:

      You should have no problems if you install Hyundai panels and — unlikely even you do — they have a 25 year product warranty, so you should be covered even if your installer disappears.

  36. This article is 7 years old and showing its age. Wouldn’t it be good to archive this or at least provide an update post script advising the latest price comparison and performance differences?
    A little misleading I think.

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