Sunpower solar panels reviews

SunPower is an American firm that provides high quality, tier one solar panels - that are now primarily being produced through its spinoff company Maxeon - that are among the best available. Their panels have the highest efficiency currently on the market, they are likely to be the best at tolerating partial shade, and they have a 25 year replacement product warranty. In addition, SunPower panels are corrosion resistant which makes them suitable for installation anywhere in Australia.

SunPower have an Australian office in Melbourne.

Read All About It

I looked into SunPower panels in June 2016 and you can read what I wrote about them here.  I also wrote about how SunPower replaced some panels under their performance warranty in 2018 here.

Production Capacity And Output

At the start of 2018 SunPower's had 1.2 gigawatts of solar cell manufacturing capacity and 1.9 gigawatts of solar panel manufacturing capacity.

In 2019, the company shipped  2.5 GW of modules, representing 80% growth over 2018.

Current production capacity isn't clear, but was expected to be boosted significantly under Maxeon.

Manufacturing Locations

SunPower is as American as apple pie and so is majority owned by a French oil company. This makes sense because the French were eating apple pies long before Americans ever did.

SunPower's headquarters are in San Jose in California.  They abandoned manufacturing in the United States for a long time but then resumed at a plant they bought from SolarWorld Amercias in order to avoid Trump's solar panel tariffs. But in January 2021, SunPower announced it was closing its Hillsboro plant. This means Maxeon will be producing all SunPower branded panels very soon.

Currently SunPower (Maxeon) has other manufacturing capacity in Malaysia, the Philippines, and Mexico.  They also entered into a joint venture to produce their P series panels in China.

Company History

SunPower was founded in 1985 by Richard Swanson. He's a great guy. He's huge in solar. He has all the best solar ideas. And his hands are at least average size.

Swanson is responsible for Swanson's Law, which states that for every doubling of production capability, the cost of solar panels fall by 20%. Despite ups and downs in prices, it's proven to be roughly accurate and I hope the effect will continue into the future.

As it has managed to stick around for 35 years so far, SunPower is one of the oldest solar panel manufacturers in existence.

However, in November 2019, SunPower announced it will spin off much of its solar panel manufacturing into a new company – Maxeon Solar Technologies. That process was completed in August 2020 and now the company's panels are marketed under the name "SunPower Maxeon".

SunPower Maxeon's 25 Year Replacement Product Warranty

SunPower provides their panels with a 25 year product warranty. This is far superior to the 10, 12 or 15 years still offered by most tier one panel manufactueres. This makes their product warranty and performance warranty the same length at 25 years each.

SunPower's product warranty is a full replacement warranty. This means that if one of their panels fails, SunPower won't just give you a refund or a replacement, they will send someone out to replace it free of charge. Because replacing a solar panel can can more than the cost of a panel this is useful.  However, under Australian consumer law, when a product fails under warranty it is possible to claim compensation for damages and loss from reasonsonable forseeable expenses such as the cost of installation.  This means technically all solar panel warranties in Australia should be full replacement warranties.  But it is still good that SunPower clearly states in their warranty they will replace faulty panels without charge.      

Panel Reliability

While this figure is now out of date, SunPower has  previously said their panel failure rate is only 1 in 37,000. Hopefully it's even better now, although I know some panels have been replaced under warranty.  Because the large majority of their panels were well under 25 years old at the this doesn't mean there is only a 1 in 37,000 chance of a panel failing during its 25 year warranty period, but it still suggests they are very reliable.

SunPower Panels Resist The Effects Of Heat

SunPower panels suffer considerably less decrease in efficiency due to the effects of heat than the average panels.  Their coefficiency of Pmax ranges from around is -0.29% to -0.37%/°C depending on the model, while the average is around -0.4%.  This is how much their output is decreased by for each degree celcisus the panel temperature is above 25 degrees.  Note that the temperature of panels in the sun can be much higher than the air temperature and can reach 65 degrees on hot days. 

SunPower Panels Tolerate Partial Shade Well

Partial shade can cause a major reduction in the performance of solar cells as one badly performing solar cell can drag down the performance of others, so just one bird poop can have a major effect. But SunPower uses various technologies to minimise its impact.

Note that if SunPower panels are connected to a string inverter the worst performing panel will still drag down the performance of other panels on the string. This problem can be overcome by using DC optimisers or by using microinverters instead of a string inverter.

SunPower Had Financial Difficulties

SunPower had been experiencing financial difficulties, posting significant losses in 2015, 2016, 2017, 2018 and 2019.

For the fiscal year 2019, SunPower's assets and liabilities were almost equal, which is not a good situation to be in.  Their financial position has been hurt by falling solar panel prices and also President Trump's US solar tariffs -- despite SunPower winning an exemption. 

There was speculation that SunPower would go bankrupt, but the recent move to shift all solar panel manufacturing to Maxeon may play out well.

But even if I was certain SunPower wouldn't be around in the future to honour their warranties, I would still be fine with installing them on my roof because their high reliability means the chance of me needing their warranty should be extremely small.

Warranty claim procedure for orphaned Sunpower customers

If you have purchased Sunpower panels from a solar installer that has gone out of business, the responsibility for warranty claims falls to Sunpower. They can be contacted on 1800 786 769, and will arrange for an installer in their network to diagnose and rectify any problems with the panels - with labor costs involved covered by the warranty.

My Recommendation

I would have no problem installing SunPower panels on my roof, and this would be the case even if I expected SunPower to go bust and not be around to honour their warranties.

But while SunPower panels are very high quality, they do carry a hefty premium and so it will be necessary to decide if they are worth the extra expense.