SunPower is one of the most respected names in the solar panel industry across 30 countries, and manufactures some of the best solar panels available. Its unique niche has been developing the highest-efficiency solar panels on the market, and the SunPower Maxeon 3 is a great example. 

SunPower recently announced that it would extend its standard warranty of 25 years to a full 40 years for the Maxeon 3. At the time, this was the longest warranty in the solar panel industry on the market. Others have since gone on to offer lifetime warranties. The extended warranty was based on a failure analysis program which reported a remarkable 0.005% return rate based on the warranty claim data of more than 15 million panels. 

The new warranty also guarantees a minimum power output of 88.3% in the fortieth year. In other words, the power output of the SunPower Maxeon 3 will only degrade by roughly 0.25% every year over the entire warranty period. 

SunPower attributes the low degradation of the Maxeon 3 to its patented metal foundation, which has been designed to better withstand thermal stresses and dissipate more heat, which reduces its vulnerability to hot spot formation and micro-cracks. 

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Technical information

The SunPower Maxeon 3 is the new 104-cell format flagship solar panel product of the SunPower range. Available in sizes from 370-400W, and based on Gen 3 high-performance IBC cell technology, this is one of the most powerful residential solar panels on the market, with 22.8% maximum efficiency. The SunPower Maxeon 3 uses layers of copper and aluminium that extract electricity  with no unsightly grid lines or busbars on the front, making the panels discreet and more durable. 

  • Range: 370W – 400W
  • Efficiency: 19.8-22.8%
  • Warranty: 40 years 
  • Cost per panel: From £350

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Key features

Sunpower Maxeon 3 fits well within a modern setting

The Sunpower Maxeon 3 generates more power with fewer panels. (Image credit: SunPower)

Highlights: SunPower offers the highest warranted power output protection in the solar industry (88.3% after 40 years). 

Key benefit: The 400W panel will generate more power with fewer panels, with 22.8% maximum efficiency. 

Service:  Repair, replacement or refunds are offered on any defective panel for 40 years. Removal, shipping and installation are included in certain countries, including the UK. 

Warranty: SunPower offers a 40-year warranty on the Maxeon 3 range and claims that customers are much more likely to return a conventional solar panel than a SunPower panel.

Cost: Starting at £350 per panel, the Maxeon 3 is one of the pricier models on the market, but with a generous 40-year warranty and high efficiency, it’s well worth the price tag. 

Pros and cons


K2 installation of the Maxeon 3 solar panels

An innovative installation of the Maxeon 3 solar panels to capture maximum sunlight (Image credit: SunPower)

SunPower talks about some valuable advantages for the Maxeon 3 solar panel for homeowners who want to install solar power in their homes, including:


  • Market-leading energy efficiency: While the majority of residential solar panels have an efficiency of around 20%, the SunPower Maxeon 3 has an efficiency of up to 22.8%, making it one of the market leaders in the UK (based on datasheet review of websites of top 20 manufacturers per IHS, as of June 2021).
  • Greater output: By upping the output of the Maxeon 3 to 400W, homeowners can generate 60% more energy in the same roof space in the first 25 years compared to a conventional solar power fit-out. 
  • High durability: In testing across 800,000 panels and 264 sites, SunPower Maxeon solar panels demonstrated the least degradation in the industry.
  • Attractive warranty: SunPower offers a 40-year year warranty on Maxeon 3 solar panels, which includes repair, replacement or refunds, as well as shipping and installation in certain countries, including the UK. 

However, there are a few disadvantages to SunPower Maxeon 3 to consider as well: 


  • Installation: To take advantage of the warranty, all SunPower solar panels must be installed by a SunPower-certified company. Installation availability and service levels may vary depending on your location, as per SunPower’s website. 
  • Cost: While costs are opaque, online price comparison sites place the cost of the SunPower Maxeon 3 400W solar panels at £350+ (per panel, installation and labour excluded), making it more an expensive option for homeowners. 

How the SunPower Maxeon 3 works 

The SunPower Maxeon 3 has a truly innovative design. These solar panels do have grid lines but are unobtrusively all-black, with back-contact conductivity via an Integrated Back Contact (IBC) copper grid in order to absorb more sunlight. The Maxeon 3 was designed to harvest the greatest amount of energy possible from a limited area, making it ideal for a home with a smaller roof.

SunPower Maxeon 3 add-ons

There is an alternating current solar panel version of the Maxeon 3 called Maxeon 5, which includes integrated microinverters to convert electricity to AC, which can be used in your home or exported to the National Grid. This comes at an additional cost, however. 

How does the SunPower Maxeon 3 compare to other solar panels?


SunPower Maxeon panels on a domestic roof

SunPower Maxeon panels are one of the most sustainable options on the market (Image credit: SunPower)

It’s hard to beat the SunPower Maxeon 3 in terms of warranties and performance. However, homeowners who want high-performance from their solar panels but not the price tag of the SunPower Maxeon 3 may want to consider LG’s NeON R solar panel

It contains 66 cells in its design, which accounts for its efficiency, and the wiring is integrated at the back of the panel to avoid shading. In terms of output, the NeON R has the SunPower Maxeon 3 beaten with a 440W solar panel option. LG claims that the NeON R will generate 92% capacity after 25 years, which is when its warranty ends. While the NeON R can’t compete with SunPower’s lengthy warranty, it’s slightly cheaper (starting from £265 per panel) and a safe bet in terms of durability. 

Homeowners should also consider the Project Solar Evolution Elite. It offers a fair output of 345W but with a lifetime product and performance warranty and an up to 30-year peak power warranty. Project Solar UK is the new kid on the block but has done extremely well in recent years. 

The SunPower Maxeon 3 offers excellent performance and a sleek roof profile, if you’re prepared to pay a little more for your solar panel system. 


What does the SunPower Maxeon 3 cost

The SunPower Maxeon 3 is considered one of the pricier options on the market. We’ve compared it here to the high-performance LG NeON R and lower performance Panasonic HIT N 245W to provide a rough comparison: 




SunPower Maxeon 3


From £350



From £250

Panasonic HIT N 245W


From £250

Maintaining the SunPower Maxeon 3 

The SunPower Maxeon 3 requires minimal maintenance, and any damage to the solar panels will be covered by its warranty. As per the SunPower website, the panels were designed with typical debris accumulation in mind. Seasonal rain should clear the debris or dust from the surface. 

However, if severe soiling occurs for any reason, it can be cleaned from the ground with a standard garden hose early in the morning or late in the evening when the panels are cooler.  

Professional reviews

“SunPower’s Maxeon 3 panels are a great choice for homeowners with limited roof space. But while there are no doubting SunPower’s impressive specifications and metrics, there are other brands on this list that offer better value if you’re on a tight budget.” 

“Maxeon 3 positions itself on the podium as one of the most comprehensive solar module options to astute energy investors. A well rounded, ultra-high performing asset to ensure uninterrupted energy production beyond an extensive 25-year period. If doing something right once to virtually set and forget is an appealing concept, then the Maxeon 3 is a shortlist must.”

“SunPower is widely regarded as a world-leading solar panel manufacturer, and very few companies can compete at the same level of performance and quality. In terms of outright efficiency, SunPower still leads the world, with the Maxeon series holding the top spot as the most efficient solar panel with the lowest degradation and best performance warranty. Although not surprisingly, the Maxeon panels are also the most expensive on the market. However, like most things, quality comes at a price. Considering that solar is a long-term investment, the higher price also equates to better performance, improved reliability, and more energy generation over the system’s life.”

Customer reviews

“I looked into different companies, and SunPower’s panels were one of the best ones out in the market at the time. The enrollment was easy. The company that was installing it did all the legwork. We just had to sign stuff and wait for the power company to grant us or to approve the panels being placed. The customer service reps explained everything and how everything went. Everything ran smoothly and had been great so far.”

“SunPower makes saving money and saving the planet so easy. The employees did a great job explaining how my solar system for the house works. I’ve saved so much money on electricity!”

Final recommendation


Sunpower Maxeon 3 solar panels are suitable on all roof types

Sunpower Maxeon 3 solar panels are suitable for all roof types (Image credit: SunPower)

The SunPower Maxeon 3 offers high performance that continues well over its nominated 40-year period. Its generous product guarantee offers great added value and supports Maxeon 3 customers in all critical aspects of assurance with parts, service and transport coverage in appropriate areas. The reliability of its high output isn’t vulnerable to negative temperature factors, and its 22.6% efficiency is impressive. 

SunPower is a trusted brand and has been in the industry for several years, operating in more than 30 countries around the globe, providing energy efficient home improvements to homeowners, and businesses.

SunPower Maxeon 3 solar panels are an excellent option for homeowners with limited roof space, but they may not be the best choice for homeowners on a tight budget.  

Read here to find out more about solar panel installation, selling solar power back to the grid or solar panel grants.

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Our review methodology 

We conducted our research by analysing more than 500 customer reviews as well as dozens of reviews by energy efficiency and solar panel experts in the UK. We then used a scoring system based on the considerations that customers would take into account when choosing a solar panel system for their homes and evaluated the SunPower Maxeon 3 against its ability to deliver against these factors, out of a total score of 100. 

During our research, the total score was comprised of: 

  • The power rating of the solar panel  for a total score of 10 points;
  • The efficiency of the solar panel for a total score of 15 points; 
  • The pricing of the solar panel per panel for a total score of 10 points;
  • The length of the warranty for a total score of 10 points;
  • The level of service and support for a total score of 5 points;
  • Durability of the solar panel for a total score of 15 points;
  • The design of the panel for a total score of 5 points;
  • The overall performance of the solar panel for a total score of 15; and
  • Online online ratings and reviews for a total score of 15 points. 

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