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.

61 thoughts on “SunPower Solar Panels: The Complete Review

  1. Rob

    Following a 35% failure rate of Sunpower microinverters within 7 years of installation and no response from the company over the past 5 months I would fairly state that the company fails to stand behind their warranty. I would strongly recommend against Sunpower-branded products based on this experience.

  2. Janet

    I have bad experience with Sunpower. I bought my panels in 2018 and maybe these was my big mistake. First I paid for 9 panels 18000 $ and now I find out that is pretty much these amount. In order to install the panels they promised that gonna change the electrical box because it’s too small. After installing the panel they said that they gonna come for the electrical box next day. And since that day nobody appeared.
    After many complaints from my side they sent me their technician to fix the problem. Instead he removed parts of the electrical box and disconnect the system. Since that moment I pay my bills in full and nobody care about the problem. I’ll go to court!

  3. Mr.Hintz

    Hello , I am a Service Tech. @ Sun Power in Phoenix. I can’t speak for everywhere in the United States but we’ve just opened up here in Phoenix. We have been here here for about 6 to 8 months. Originally we were contracted other companies to install our panels and unfortunately SOME of these install companies didn’t have the best installers.
    Sunpower had heard an earful of issues and decided that it was time for us to open up our own SERVICE and INSTALL department here in the valley . As far as I know this goes for other states as well .
    I had read above that someone’s inverter wasn’t showing production. I’m not sure what inverter you have but I’m sure your screen shows a “communication error”. if your system is DC your PVS is showing a icon error.
    If for some reason you receive a regular bill for the normal amount, SUNPOWER will always give you back that amount on VISA gift card.
    No one wants to wait, I know . I promise though once your system is back running you’ll love it.
    We are backed up but we are working just about 6 days a week to get caught up. We have a great team of guys and a intelligent woman behind us ,giving us the job training. A majority of us came from install crews as well ,so we know what we are getting in to .
    Sunpower has some great surprises coming up this year and we are going to get our current customers back up and updated to latest greatest . Even if It cost Sunpower and arm and a leg.
    Sunpower actually cares about its previous customers. I know because it’s my job to get everyone back up and running here in Arizona.
    .. Mr.jhintz

  4. Jeff

    Too bad Sunpower does not honor their warranty. Too bad Sunpower takes years to respond to requests to repair or replace their failed system.

    Bold statements about a great warranty, until you actually need to use the warranty.

    I paid top dollar or as Sunpower says “slightly more” for a system that failed and Sunpower failed to make it right.

    Oh and the production guarantee? You guessed it, not provided as per agreement.

    Simply put, Sunpower is NOT a reputable product.

  5. Don Briggs

    I own SunPower panels. I am REALLY disappointed in their monitoring system. The one they make available to consumers is rudimentary. It’s suitable for children. In addition, they lost the ability to monitor my system on 11/26/19. I discovered this loss of communications on 12/3/19. Their “monitoring” system says, “We lost communication with your system but it’s probably working.” Well, it was not, in fact, working. And I’m married to these guys for 25 years.

  6. Erol

    Hi Jon,

    Curious to know, for your 11KW system, what Is the estimated production in LV?

    Your numbers seem great, for reference, I purchased a 9.45MW system in Westchester County, (summer 2018, so 1 yr prior), at a gross cost of $3.50/watt. Estimated annual production is ~11,300kwhr’s. Grid electricity costs in our county avg. $0.21/kwhr, so paying an extra 10-20% for our system (I assume your production efficiency must be much better given your location) is more than offset by us having some of the most expensive electricity rates on continental US.

    Just interesting that cheaper prices for installed panels available where you are, as I significantly negotiated down our contract from $4.1/watt initially. Feels like manufacturers know they can charge higher prices in Northeast where comparative electricity rates essentially protect their pricing power.

  7. Matt

    After getting multiple quotes, with rebates and incentives, going through the local master Sunpower dealer in CT was the most cost effective. They offered the most production and with an equivalent or lower price than the other quotes. Currently in the process of having the system installed and looking forward to the results.


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