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LAST UPDATED: April 18th, 2023

SunPower is synonymous with solar and solar panel technology as the company has manufactured some of the most popular pieces of solar equipment found in the United States today. The company’s cofounder, Dr. Richard Swanson was an electrical engineering professor at Stanford University and secured a grant from the Electric Power Research Institute and the U.S. Department of Energy to explore the possibilities of solar power. 

SunPower was officially incorporated in 1985. SunPower focused heavily on the advancement of solar cells and how to effectively convert sunlight into usable energy. SunPower started to mass produce its solar cells, panels, and eventually storage solutions while continuing to push the limits and advance solar technology.

The SunPower operation continued to grow and now the company has two subsidiary operations that it owns to oversee all aspects of the company’s efforts. SunPower leads the way in direct sales of commercial and residential solar solutions and is currently working on its comprehensive solar roof. The experience, financial backing, and proprietary research are all reasons SunPower continues to be a leader in solar particularly in the United States. 

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The Good

  • Panel Options
  • Efficiency and Power Ratings
  • Performance Warranty
  • Power Tolerance and Cell Type

Panel Options

There are currently three available panel series offered under the SunPower umbrella. These include the SunPower M Series, X Series, and U Series. Each come with varying specifications and metrics, but the quality, reliability, and dependability remains consistent throughout each panel option.

  • M Series — The SunPower M Series boasts the highest efficiency rating among AC solar panels providing 420–440 watts.
  • X Series — The SunPower X Series provides more power allowing for increased savings. The X series also does not require nearly as many solar panels to be installed in order to maximize power output. 
  • U Series — The SunPower U Series is the latest solar panel to be introduced by SunPower and compliments the total SunPower Equinox system.

Efficiency and Power Ratings

One clear metric that many prospective solar panel customers are interested in is the efficiency rating. This rating determines what percentage of sunlight that makes contact with the solar panel is converted into usable electricity. SunPower solar panels have one of the highest efficiency ratings in the industry reaching 22.8 percent. This is a premium efficiency rating compared to counterparts on the market. 

Another key metric to note is the impressive power ratings available through SunPower solar panels. The power output rating measures just how much electricity one solar panel can regularly produce. The higher the power output rating, the better. SunPower solar panels offer one of the highest power output ranges with the least efficient hitting 320 watts and the most efficient panel reaching 470 watts. 


There are generally two types of warranties that back solar panels. Typically, the manufacturer will offer a product warranty and a performance warranty. These cover different components of the solar panel product, and SunPower offers one of the most comprehensive coverage solutions for its clients in the industry.

Product Warranty

All SunPower solar panels are backed by a 25-year product warranty. That means if a homeowner encounters any issues with its solar panels regarding material or workmanship issues, repairs and replacements are covered by SunPower. The industry average for a product warranty is 12 years of coverage. SunPower more than doubles that. 

Performance Warranty

The performance warranty offered through SunPower is also one of the best in the entire solar panel industry. As solar panels age, a natural degradation occurs. SunPower solar panels experience an annual performance degradation that bests even its most reliable competitors, meaning SunPower solar panels will continue to produce more power over time than any other panels on the market. If for some reason the solar panels do not live up to these specifications, SunPower will correct the issue on their dime.

Power Tolerance and Cell Type

While efficiency and power ratings are key specifications to look at when making a solar panel purchasing decision, power tolerance is another metric that plays a big role in performance. Power tolerance itself determines how much power output from a solar panel can actually fluctuate, even when conditions are unchanged. A vast majority of solar panels have a power tolerance rating that sits between -0/+3% and -0/+5%. SunPower solar panels hit the -0/+5% end of the spectrum, leading many of its competitors. 

The cell type is also critical to note when analyzing the competitive advantage of SunPower solar panels. SunPower solar cells, manufactured by Maxeon solar, use different solar cells that produce high levels of electricity contributing to its industry leading power output and efficiency. 


The Bad

  • Turned Over Manufacturing to Maxeon Solar
  • Panel Expense

Turned Over Manufacturing to Maxeon Solar

SunPower has been around for decades. Over time, the company has secured financial backing and research grants to continue to advance its technology and solar products. SunPower continues to push the limits of solar panel and equipment production, and as a result, needed to offload some responsibilities.

SunPower turned over manufacturing to its subsidiary operation, Maxeon Solar. While the panels are still utilizing SunPower technology, the actual production of its solar panels is handled by Maxeon Solar. Maxeon is overseen by SunPower, but it is a separate entity, which was not the case a few years ago when SunPower still handled its panel manufacturing efforts. 

Panel Expense

It is no secret that SunPower solar panels are some of the most powerful, efficient, and dependable solar panels on the market. Because of the high quality of SunPower solar panels, that equipment comes at a cost.

Solar panels are expensive regardless of the manufacturer that produces them, but SunPower solar panels are more expensive than some competing panels. The starting price, before tax incentives and rebates, hovers aound $18,000–$19,000. That comes out to about $3.30 per watt, which is not as affordable as some other residential panel solutions. 


The Bottom Line

SunPower is a national brand with over 500 dealers spread across the country installing its solar technology and equipment. Multiple solar panel options are available through SunPower, including the M Series, the X Series, and the U Series.

SunPower solar panels continue to lead the way in efficiency and power ratings. The performance warranty and comprehensive protection available through SunPower for its equipment is some of the best in the industry. Another important feature to note regarding SunPower solar panels is its power tolerance and cell type, both components that make the SunPower solar panels one of the best on the market. 

There is no denying the reliable performance and quality of SunPower solar panels, but there are drawbacks to what the company offers that prospective clients should be aware of. For starters, SunPower no longer handles the actual manufacturing of its solar panels. That work has been transferred to its subsidiary company, Maxeon Solar. The cost to have SunPower solar panels installed is also on the higher end of the scale but that is due to the overall performance and quality of the technology and equipment.

Homeowners who want the best performing solar panels covered by the most comprehensive warranties in the industry will likely benefit from what SunPower solar panels offer. These solar panels do come at a cost, so the affordability is something to be aware of, but there are not many solar panels on the market more reliable and efficient than SunPower solar panels. 

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