SunPower X Series Solar Panels: Should You Choose Them for Your Project?

X Series solar panels by SunPower are among the best photovoltaic (PV) modules available. They feature cutting-edge technology and certified durability. These modules are among the different solar solutions by SunPower, delivering 60% more energy than conventional modules during their 25-year lifespan.

If you want to learn more about the SunPower X-Series, this SunPower X-Series review is for you. Here we will analyze the technology featured in these modules, their technical specs, strengths & advantages, compare them against other options, and explain which applications are better suited for them.

SunPower X-Series Solar Panels Guide

SunPower X-Series feature Maxeon Gen III solar cells, one outstanding solar technology available. In this section, we explain how this technology works.

Maxeon Gen III Solar Cell

Maxeon Gen III Solar Cells feature cutting-edge technology with a 24.3% efficiency, delivering 25% to 35% more power than traditional cells. The technology implements high-quality monocrystalline silicon wafers with a black antireflection coating at the front, and Interdigitated Back Contact (IBC) or All-Back contact technology with a copper metal grid with tin-coating at the back of the cell.

SunPower Solar Cell Efficiencies Comparison
SunPower Maxeon Gen III solar cells vs. competing options | Source: Maxeon Solar Technologies

These cells make SunPower X Series modules resistant to Light-Induce Degradation (LID) while delivering a low-temperature coefficient and great performance in broad light spectrums. The cells are also eco-friendly by featuring entirely lead-free components.

Technical specs & details of the X Series solar panels

Residential X-Series

Residential X-Series includes the X21 and X22 variations. The X21 features a traditional design with superior aesthetics and a power output of 335W, while the X22 modules are the latest technology, featuring a superior performance with a power output of up to 360W.

SunPower X21 and X22 Series Solar Panels
Source: SunPower X21- & X22-Series manuals
  • Module Efficiency: Up to 22.2%.
  • Nominal Output Power: 335W – 360W.
  • Temperature Coefficient: -0.29%/ºC
  • Operating Temperature: -40ºF to 185ºF
  • Dimensions: 61.3 x 41.2 x 1.8 in.

Residential SunPower X Series modules are designed to deliver more power with fewer modules installed. Featuring 96 Maxeon III solar cells with a conversion efficiency of up to 22.2%, X Series modules can deliver up to 360W for the highest power-rated module in the series, while the All-Black design can deliver up to 335W.

Each SunPower X Series module features a Class A appearance and it is protected by a high-transmission tempered anti-reflective glass with a Class 1 black anodized frame. The modules are resistant to extreme climates and are covered by SunPower’s 25-year warranty.

Commercial X-Series

Commercial X-Series features a slight variation between the X21 and the X22 options. The X21 features 128 solar cells for a power output of up to 470W, while the X22 modules feature 96 cells for an output of 360W.

SunPower Commercial X-Series Solar Panels
  • Module Efficiency: Up to 22.2%.
  • Nominal Output Power: 360W / 445W – 470W
  • Temperature Coefficient: -0.29%/ºC
  • Operating Temperature: -40ºF to 185ºF
  • Dimensions: 61.4 x 41.2 x 1.8 in. / 81.4 x 41.2 x 1.8 in.

Commercial SunPower X-Series is designed for commercial and utility-scale applications, featuring 96 and 128 Maxeon Gen III solar cells to deliver 360W for the X22 and 445W-470W for the X21 options. The size between both options also varies.

These modules feature a B Class appearance and are protected by a high-transmission tempered anti-reflective glass with a Class 2 silver anodized frame. They have a slightly lower resistance to extreme climates than residential variations but are also covered by a 25-year warranty.

Strengths & advantages of the SunPower X-Series

SunPower X-series features many strengths and advantages, making them excellent solar solutions for various applications. These are some of their main strengths & advantages:

Durable & Resistant Design

A tin-copper and slightly flexible design for the Maxeon Gen III solar cells makes the SunPower X-Series resistant to corrosion and cracks. They are also resistant to Light-Induced degradation, resulting in a higher power energy output of 2% to 3%.

More energy is delivered during its lifetime

Combining high durability with outstanding performance, SunPower X Series modules can deliver 60% more energy compared to traditional modules. In the first year, these modules deliver 45% more power than traditional options, but by their 25th year, they are producing 81% more power than conventional ones.

Better performance at high temperatures

SunPower X-Series Performance Chart
SunPower X-Series vs. conventional modules | Source: SunPower

Maxeon Gen III solar cells feature a low-temperature coefficient of -0.29%/ºC. This means that SunPower X Series modules can produce around 1-2% more energy at a high temperature of 35-40ºC, making them extremely suitable for regions with hot climates.

Increased performance under different light conditions

The performance of SunPower X Series modules is improved in overcast and low-light conditions, thanks to the cutting-edge technology in Maxeon Gen III solar cells. This increases the energy output of the SunPower X Series by around 1% compared to traditional modules.

25-year warranty

SunPower X-Series are designed to be lasting and durable, which are covered by SunPower’s 25-year warranty for the product and performance.

Highly aesthetic design

The X21-Series features the key signature All-Black design of SunPower, delivering a great power output without disrupting the aesthetic of the house. This feature makes them a unique solar solution in locations where aesthetics is a key factor for the installation of PV modules.

Comparing SunPower X-Series

To comprehend the reach of the SunPower X-Series, it is better to compare them against competitor options and even other modules designed by SunPower. In this section, we make these comparisons.

SunPower X-Series vs. 360W DNA 120 Aptos Solar

DNA 120 solar panels by Aptos Solar, are a popular option in the U.S. as well that competes against the SunPower X-Series. Let us contrast both options against each other.

SunPower 360W X-SeriesAptos Solar 360W DNA 120
Module Efficiency22.2%19.73%
Nominal Power360W360W
Temperature Coefficient-0.29%/ºC-0.36%/ºC
Module Dimensions61.3 x 41.2 x 1.8 in69.13 x 40.90 x 1.37 in.
Weight41 lbs.45.19 lbs.
Warranty25 years30 years

Both companies have designed PV modules featuring a 360W power output, but they feature different technologies. Maxeon Gen III solar cells have an efficiency of 22.2%, while DNA split cells only reach an efficiency of 19.73%. This makes that for Aptos Solar modules to produce 360W, they have to be larger and 4.09 lbs. heavier than the SunPower X-Series.

The temperature coefficient is another key difference between both modules. With a temperature coefficient of -0.29%/ºC, SunPower X-Series has a better performance in hot climates than DNA 120. The only aspect where Aptos Solar’s DNA 120 surpasses SunPower X Series is in the warranty; these modules feature a warranty 5 years longer, for a total warranty of 30 years.

SunPower X-Series vs. M-Series

Comparing the SunPower X-Series vs. M-Series, allows us to learn key differences between the two solar solutions designed by SunPower.

SunPower 360W X-SeriesSunPower 440W M-Series
Module Efficiency22.2%22.8%
Nominal Power360W440W
Temperature Coefficient-0.29%/ºC-0.29%/ºC
Module Dimensions61.3 x 41.2 x 1.8 in73.7 x 40.6 x 1.26 in
Weight41 lbs.48 lbs.
Warranty25 years25 years
Number of Cells96 Maxeon Gen III Cells66 Maxeon Gen VI Cells
Built-in InverterN/AEnphase IQ7HS

There are several differences between the SunPower X-Series vs. M-Series, like their technology, power output, and signal output type. M Series modules feature 66 Maxeon Gen VI cells which are larger and feature a conversion efficiency of 22.8%. The M-Series featuring a larger size, reach a power output of 440W, which is far superior to the 360W of the X-Series.

The built-in inverter of the M-Series creates another major difference. This inverter produces an AC output of M Series modules, instead of the typical DC output in the SunPower X-Series. While these are similar panels, the M-Series has several advantages over the X Series.

SunPower X-Series vs. A-Series

The SunPower X-Series vs. A-Series generates another interesting contrast. The A-Series is highly similar to the M-Series, including the AC output but featuring a slightly older Maxeon solar cell technology.

SunPower 360W X-SeriesSunPower 425W A-Series
Module Efficiency22.2%22.8%
Nominal Power360W425W
Temperature Coefficient-0.29%/ºC-0.29%/ºC
Module Dimensions61.3 x 41.2 x 1.8 in72.2 x 40.0 x 1.2 in
Weight41 lbs.46.5 lbs.
Warranty25 years25 years
Number of Cells96 Maxeon Gen III Cells66 Maxeon Gen V Cells
Built-in InverterN/AEnphase built-in microinverter

SunPower A-Series features Maxeon Gen V cells with an efficiency of 22.8%, featuring 65% larger cells than the Maxeon Gen III. The A-Series also features a larger size and weight, but instead of having the 360W for the M-Series, the nominal output goes up to 425W.

Performance in hot climates remains the same since both of them feature the same temperature coefficient. They also feature the same warranty.

When to choose the X-Series for your project?

SunPower X Series modules feature older technology than the A- and M-Series, but they have similar conversion efficiencies and are far better than conventional options in the market.

Residential projects looking to produce higher power outputs on small rooftops can benefit from the SunPower X-Series. These modules can be a game changer on rooftops with limited space since smaller modules can be rearranged in different shapes to better fit the roof. This makes it easier to fit more X Series modules than A- or M-Series which have a larger size.


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