SunPower solar panels review

SunPower Solar Panels: The Complete Review

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SunPower solar panels are one of the most frequently requested solar panel brands on the EnergySage Solar Marketplace, and for good reason. SunPower panels are often the most efficient (read: powerful!) products on the market today, and they offer an industry-leading warranty. For many years, SunPower has been a fully-integrated solar shop: manufacturing solar cells & panels, and then offering sales and installation services for residential and commercial applications as well. Recently, SunPower announced that they’re spinning off their manufacturing arm into a new company–Maxeon–to focus on installing solar panels.

How SunPower X-Series, E-Series, and A-Series solar panels compare to other panel manufacturers

As you evaluate overall solar panel quality, there are four key metrics that you should consider: efficiency, performance, warranties, and price. To help you with your decision, EnergySage has developed SunPower reviews for each metric, along with a comparison of SunPower solar panels (including the esteemed SunPower X-Series) against the other leading panel manufacturers offered on the EnergySage Marketplace.


The term “solar panel efficiency” refers to how well a solar panel can convert sunshine into useful electricity. Given the same conditions, a high-efficiency solar panel can produce more electricity than a lower-efficiency panel of the same size. For this reason, a higher efficiency rating is generally preferable.

SunPower solar panels are the most efficient panels currently available on the market in the United States. While the majority of solar panels fall in the 14% to 18% efficiency range, SunPower’s products are much more efficient – between 19.6% and 22.8%. If efficiency is your top priority, the technical specifications of SunPower solar panels are unparalleled.

Performance (temperature coefficient): SunPower X-Series

For this portion of EnergySage’s SunPower reviews, we use the temperature coefficient as an indicator of panel performance. The temperature coefficient represents how well your solar panel can handle less-than-ideal conditions. Solar panels, like other electronics, perform their best when they are kept cool (ideally around 25° C/77° F). You can use the temperature coefficient to get a sense of how your panel’s performance will change during hot sunny summer days.

For every degree above 25° C (77° F), your solar panel’s electricity production will decrease by its temperature coefficient. For example, SunPower’s SPR-X21-345 panel has a temperature coefficient of -0.3%/°C. This means that, if the panel’s temperature increases by one degree from 25° C (77° F) to 26° C (79° F), its electricity production will be reduced by -0.3%. If its temperature increases all the way to 35° C (95° F), electricity production will decrease by 3%.

Ideally, you want the lowest temperature coefficient possible. SunPower’s solar panels offer some of the best temperature coefficient ratings on the market today, between -0.35 and -0.29.


Whether you’re buying a TV, a car, or solar panels, the manufacturer should stand behind their product with a strong warranty. A solar panel’s materials warranty (sometimes referred to as the product or equipment warranty) guarantees that it will be replaced in the event of equipment failure due to manufacturing defects or environmental issues.

Most solar panel manufacturers offer a 10-year materials warranty, but the best solar panels come with a 12, 15, or even 25-year warranty. In keeping with SunPower’s industry-leading position in the other metrics we’ve assessed, the company offers a 25-year warranty against any defects in their products.

Every solar panel’s production naturally degrades over time. The performance warranty is a manufacturer’s guarantee that your solar panels’ production won’t degrade too quickly. In addition to a leading materials warranty, SunPower offers one of the best performance warranties of any solar panel manufacturer we’ve reviewed. Most solar panel brands offer a performance warranty stating that their panels will still be producing at somewhere between 80% and 83% of their original capacity after 25 years. By comparison, SunPower’s performance warranty is 94% after 25 years – a full 9% to 12% higher than most other panel manufacturers offer.

How much do SunPower solar panels cost?

Our SunPower reviews wouldn’t be complete without a discussion of how much SunPower solar panels cost. As you might expect, if you want to invest in the highest-quality solar panels available, you’ll end up paying a higher sticker price as a result.

However, the price of SunPower solar panels might not be as high as you think. We reviewed quotes offered on the EnergySage Solar Marketplace that included SunPower solar panels and found that these systems were priced between $3.14/Watt and $3.56/Watt. By comparison, the average price on the Marketplace during the same time period was $2.76/W – SunPower systems were pricier, but not by an astronomical amount.

This means that, for a 6 kW system, your gross cost would be anywhere from $18,840 to $21,360. However, remember that most homeowners end up paying much less than the total gross cost. There are plenty of solar incentives and rebates to help you reduce upfront costs, including the 26 percent federal tax credit for solar.

How to find the best price on SunPower solar panels 

SunPower panels are, without a doubt, some of the best solar panels available today. When EnergySage ranked the best solar panels on the market, our SunPower reviews were the highest of any panel brand.

If you have a limited amount of space and need to maximize your solar panel system’s production, you can’t go wrong with an installation that includes SunPower solar panels. However, not every homeowner needs the most efficient panels available on the market. If you have enough space for a larger system, installing slightly less efficient panels may give you the performance you need at a slightly better price.

The best way to determine whether SunPower solar panels are the best solar panels for your home is to review multiple quotes with different solar equipment options before making a decision. When you compare all of your options on the EnergySage Solar Marketplace, you’ll find the right combination of price and quality that meets your needs. When registering, simply note in your profile that you’re interested in receiving quotes that include SunPower solar panels for your home. Many of our qualified, pre-vetted solar installers are part of SunPower’s certified solar installer network, which means you can be confident that every aspect of your solar system installation meets the highest standards.

60 thoughts on “SunPower Solar Panels: The Complete Review

  1. Danno

    Wow, this is scarey to read. I had Sunpower installed and activated just 3 weeks ago, so far so good.
    My 9.45 KW system has been pumping out over 40KW each sunny day since, I sure hope it continues…

  2. Joesph Jones

    Just wanted to thank the many many individuals who took the time to relate their experiences with Sunpower. I have been investigating solar manufacturers and sellers as I plan to go solar this year.
    Thanks to the wonderful heads up I actually canceled a sales call with the local Sunpower sales rep.
    If there is one thing I’m not looking to purchase it’s more headaches.

    1. Georgia

      Great job! I think that was a great idea. I purchased these and the follow thru from Sun Power is TERRIBLE. I have had issue and have wasted hundreds of hours resetting my system and fighting with Sun Power to do the appropriate warranty work. You definitely saved yourself some headaches!

      1. PT

        Just checking, but are you based in the Philippines? I’m wondering if support/service varies largely based on country/region.

    2. Georgia

      Great to hear. I hope Sun Power starts to realize the way they do business DOES impact their business.

  3. Tom Lammie

    I have an 8kw sunpower system with their 230 panels and an 8kw sunny boy. It has been faultless over the past 10 years with little to no discernible power degradation. Which brings up something I wish the author had noted when making the cost comparison, that KWH is where the homeowner’s value comes from, not KW’s. I hope the guys having trouble with the start up don’t give up, and come back and say how its going a year or two down the road.

    1. Georgia

      They were smart if they gave up. It isn’t just about KWH…it is about the actual system and panels. The system has ISSUES…and to boot, Sunpower does NOT have a good warranty process. The warranty sounds good until you have to use it. I have been out solar power (unless I reset the system myself) for months. It takes FOREVER for them to resolve the issue. They will not let my installer fix the problem and route me thru a sub-contractor over 3 hours away because my installer isn’t “trained” to make the repairs…but all they are doing is reinstalling parts that are failing. DUMB DUMB DUMB. Between hours lost on solar power, my manually having to reset the system and hours on the phone to argue for repairs they SHOULD be making I have wasted hundreds of hours. If you value your time and want to be respected as a customer DO NOT BUY SUNPOWER!!!

  4. James Dickinson

    You are better off using LG, Panasonic or Qcell panels and Enphase micro-inverters. Find a local electrician or solar installer. You’ll save 20% or more…and have the same warranty.

  5. Mike L

    I’m surprised by these comments, and hope you guys get it resolved. We purchased our 24 panel system last year, and went with the SunPower Corporation X21 SPR-X21-350-BLK-E-AC panels. The plan was to go with a system that produced 80%-85% of our power needs, it is at 86.6% to date, and we are obviously quite pleased. I don’t know if your initial survey was accurate, or if there were any installation issues, but Freedom Solar here in San Antonio, Tx was referred to us by a friend that used them years earlier, and they were very professional. Good luck!

    1. Georgia

      The problems will come when you go to use the warranty they promise. If you have the diodes they will fail…and they will make you wait weeks to prove the failure before they replace them. Then it will still have failures and they will waste you time with more site visits before they approve the next step repair. Per their own local technicians I need a new inverter, but the engineers (located in the Philippines) won’t approve it. WTH

  6. Sunny Wang

    We installed SunPower and had its operating permit about a month ago but it never worked. It took us multiple calls to get a technician. It finally worked with the technician’s help but only to stop working (loss of communication) the next day. We waited a few days to see if it can come up and running again automatically but it didn’t. We called about a week later asking the rep to send a technician but their representative Shane told us toast they don’t have the technician’s report yet, so they can’t send anyone until they looked at the report! How long did it take to generate the report I asked and she said usually in a couple of days. But no, they don’t have the report after a whole week and they won’t send a technician until they read the report which no one knows when will be generated, We spent a lot of money purchasing SunPower but SunPower won’t make a good effort to timely send its technician end make it work! Very disappointed.

    1. Monkeyvibes

      Sunpower isnt the best at providing customer or technical service. I made the mistake of purchasing a Sunpower solar system and havent had anything close to the reliability and power production Sunpower claimed I would. The system is non functional more than functional by a huge margin. If Its been working 10% of the time since installation I would be really surprised !

    2. Leo Torres

      Wow, we just have almost similar situation
      Last year ee had production loss for a good 6 7 months. I asked for reimbursement but was denied. Now 2021, we have started having issues again. I was told by Sunpower support that there are inverters having issues, case no. created, forwarded to HES solar and no response so far. I was told by my neighbor to get access to monitor inverter. Great idea.

    3. Georgia

      I am so sorry. Sounds like you are having multiple issues like I am. Their actual follow thru on customer service after installation is TERRIBLE! I hope everyone continues to read these reviews and doesn’t install this mess of a system!

    4. John Ware

      Where are you to have this unfortunate experience? We are considering SunPower in CA, but your comments are very concerning.

  7. Edwin Diaz

    Wow Sunpower what’s going on? Sounds like you guys need more technicians. Give me a call i can help service the LA Area.


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