If you are interested in high efficiency solar panels, here we will review SunPower solar panels .

Sunpower solar panels are the most efficient panels available in the market today. Along with the best product warranty, it is understandable that Sunpower is one of the most requested brands.



All this comes with a price tag. Next, we go to the smallest detail, why or why not choose Sunpower.

To evaluate a solar panel brand, you must observe some important criteria, such as:

  • Return
  • Warranty
  • Price
  • Performance as the temperature coefficient and tolerance.

What is the Efficiency of Sunpower solar panels?

The highest efficiency that exists in a solar panel:

A conventional solar panel with dimensions of 1.7 x 1.0 meter can be between 250W and 320W. However, a SunPower solar panel, with smaller dimensions, has powers from 327W to 370W.

We are going to exemplify it in a simple table, comparing some of the  most efficient panels of the market  that are commercialized regularly. You will see what we mean:

SunPowerX22-360360W1,559 x 1,046 x 46 mm22.2%
SunPowerX21-345345W1,559 x 1,046 x 46 mm21.5%
LGNeON R 360360W1,700 x 1,016 x 40mm20.8%
SunPowerE20-327327W1,559 x 1,046 x 46 mm20.4%
AUOSunForte 330330W1,559 x 1,046 x 46 mm20.3%
SHARPNQ-R256A256W1.318 x 980 x 46 mm19.8%
PanasonicVBHN330SJ47335W1.590 x 1.053 x 35 mm19.7%
PanasonicVBHN325SJ47325W1.590 x 1.053 x 35 mm19.4%

The great difference of efficiency of SunPower with the others is clearly appreciated. It is the most technologically advanced cell that exists. In any case, we could also highlight the HIT cells of Panasonic Sanyo, which is also an exclusive technology with superior performance.

SunPower Solar Panels are Different, they are simply Better

The SunPower photovoltaic panels of the E and X series have a series of characteristics that  no other photovoltaic panel has . We list some:

  • A SunPower cell has a  very different design from a conventional cell , because it is made on a copper base.
  • Copper-based cells are   more expensive than conventional cells, but a much more reliable and high-performance cell is achieved  .
  • SunPower cells are deposited on a tough copper base with maximum durability, while conventional cells have their contacts printed directly on the cell (such as screen printing on a T-shirt).
  • The SunPower panels of the X series have a maximum annual degradation of -0.25%, so their  performance is 92% at 25 years,  when the conventional in the rest of manufacturers is 85% at 25 years.

View of a SunPower cell and a conventional cell:



The differences are not only aesthetic. Although the SunPower cell does not have front contacts and, therefore, in view is a completely “clean” and black cell, we must also highlight the  enormous difference in efficiency  that exists between a SunPower cell and the rest that are available today in day.

Solar energy guarantee

Sunpower also has no rival in terms of warranty here. Sunpower uses a very transparent guarantee for both capacity and product warranty.

  • Warranty  Product  : where most brands offer a guarantee level 1 10 to a maximum of 15 years in Sunpower, this is no less than 25 years! And this does it for a good reason. According to Sunpower, only 1 in 20,000 solar panels goes wrong (and what is replaced).
  • Production guarantee : together with the product warranty, the production guarantee is also unprecedented, or rather low. With a loss of 13% in 25 years. therefore, they retain 87% of their return. This is a loss of 0.5% per year. Where most brands cover around 0.7% of losses per year, 0.5% is a great improvement.

If the solar panel no longer meets one of these two requirements, the solar panels will be replaced free of charge. Only in case of abuse, improper installation or when the solar panel has been moved from its original location.

What is the price of Sunpower solar panels in 2019?

Sunpower solar panels are, so to speak, one step higher than the traditional brands of Tier 1 solar panels. This is also reflected in the price.

Sunpower is practically the most expensive brand of solar panels, even in € / Wp. But the unprecedented warranty on the product and power means that the price is justified.

In general, a Sunpower solar panel is, on average, 50% more expensive than the other Level 1 brands.

Is the price justified? As far as we are concerned, yes. Sunpower invests heavily in research and development and represents innovation.

Because  solar panels  also get much better performance, up to 45% more than other Level 1 brands, it is ideal for installations where there is little space available due to a small roof or a part in the shade. This also means less assembly and material costs.

What is the performance of SunPower solar panels?

You can easily see the performance of a solar panel when viewing a solar panel data sheet. We evaluate the performance of Sunpower solar panels based on the temperature coefficient (Pmax) and tolerance.

Temperature coefficient

The X-21 series, the best Sunpower segment, has a Pmax of -0.30% / ° C. Everything below -0.30% / ° C is recommended. For example, a loss of 9% occurs at a temperature of 25 degrees (55 degrees in solar panels), while with other panels this is quickly 15%.


No Sunpower solar panel has a negative tolerance. The X-21 series has a positive tolerance of 5%. This means that solar panels yield up to 5% better than indicated. With a series of 345 watts X21 this is a bonus of more than 17 watts!

Solar energy solar panels

The Sunpower range consists of 2 series:

  • Series X: X-20, X21 and X-22
  • E-series: E-20

Sunpower series x

This is the Sunpower masterpiece, especially the X-22. The X series is the result of 25 years of research. The X series consists of Maxon solar cells that are manufactured with as little metal as possible. As a result, they absorb more sunlight and achieve a performance of not less than 21.5%.

The X series has been on the market since 2013 and, since then, there is no single brand of solar panels that approaches the quality of this solar panel.

Because the efficiency is so high, you get up to 45% more electricity from a solar panel than any other brand. The X-21 is entering

X-20  : the first panel of the X series is the X-20. With a yield of 20.3%, this monocrystalline solar panel is still among the best solar panels today, although it was produced in 2010. The panel supplies 327 W of power and has a tolerance of -3% / + 5% .



X-21  : The X-21 model is the successor of the X-20. With a yield of 21% and a positive tolerance of + 5%. There are 2 versions, the X21 Signature Black with a power of 335W per panel and the standard version of X21 with a power of 345W.

The Signature Black panel is often chosen because of its design, which looks much tighter and is better suited to dark ceilings. The X-21 won the most efficient solar panel award in 2012.


The solar cells in the X-21 panels are built on Maxeon technology. This solar cell is built from a solid copper frame, which makes it virtually impossible for corrosion to occur or for the material to degrade.

X-22  : the X-22 model is Sunpower’s top solar panel. With an unprecedented efficiency of 22.1% and a positive tolerance of 5%, it offers no less than 360 watts of power per panel.

The Pmax is also unprecedentedly low with -0.299% / o C. Like the entire X series, the panel comes with a product warranty of 25 years and a power guarantee of -0.4% for 25 years.


E-20  : The Sunpower E-20 is a monocrystalline solar panel with Maxon Gen II solar cells. Like all Sunpower solar panels, performance is high, with no less than 20.4%. An E-20 panel provides 327W of power, which makes it an ideal solar panel when the available space is not large.


Installers of solar panels Sunpower.

Many installers today offer Sunpower premium solar panels in their range. Some installers consciously choose to work alone with Sunpower, with other installers this is part of their assortment, which usually contains 4-5 marks. Below are some reliable Sunpower installers.

Publicaciones relacionadas

Botón volver arriba