Updated Nov. 12, 2015

Editor's note: Because we are aware that many SunPower panels being produced and shipped to customers have a higher efficiency than the current world record, we recently pulled a residential panel with a high power rating out of a California warehouse and sent it to the National Renewable Energy Laboratory for testing. The panel, part of a shipment for a residential installation, was verified by the NREL to have an efficiency of 22.8 percent, based on the area of the glass, setting a new world record. 1

As one of the world’s most innovative solar companies, SunPower is proud to design, build and install products that lead the industry in durability, reliability and efficiency.

Let’s take a look at efficiency. When you hear people talking about solar panel efficiency they are referring to the amount of sunlight that is absorbed by a solar panel and converted into power for a home or business.

Conventional solar panels are about 15 to 18 percent efficient, meaning that 15 to 18 percent of the sunlight they’re receiving is absorbed and turned into electricity. 3

SunPower has long been recognized as the industry leader in offering the highest efficiency solar panels on the commercial market. 2 Our most efficient solar panel, the SunPower® X-Series solar panel has a nameplate value of 21.5 percent efficiency and has been available to customers since 2013.

In some cases we are finding that these panels are exceeding 22 percent efficiency, as verified by the U.S. Department of Energy’s National Renewable Energy Laboratory.

While there is competition in our industry, it’s to the benefit of consumers. As a result of healthy competition, for example, we’ve seen the cost of the average price of a residential solar system drop 45 percent since 2010, according to the Solar Energy Industries Association.

It’s important to understand the key features of solar panel technology that enable a panel to efficiently and reliably deliver power through 25 years or more of rain, shine, wind or ice and other weather conditions Mother Nature may bring.

What makes SunPower solar panels different?

Take a look at this video, where we introduce SunPower's then-new high efficiency X-Series panel and explain the product’s innovative technology, an overview that’s still relevant today.

The SunPower X21 panel is the culmination of more than 25 years of research and testing. It is comprised of SunPower® Maxeon® solar cells, which are free of the metal ribbons striped across conventional panels, allowing our cells to absorb more sunlight while looking great on your roof. Maxeon cells feature full copper backings to combat the foes of rooftop solar: moisture and dramatic temperature swings.

Extreme weather and years of exposure can increase breakage and reduce power production and efficiency of conventionally constructed solar cells. (Here’s another video that shows how easily a conventional solar cell snaps into pieces compared to a SunPower solar cell, which remains intact.)

The solid copper backing of SunPower cells, however, makes them massively strong and almost impervious to corrosion. The thick connectors we use between cells on our panels ensure that expansion and contraction from daily temperature swings is not a problem.

In fact, while hot temperatures cause conventional panels to produce less energy, ours maintain performance, producing 38 percent more power per panel.4

Because our panels are so reliable, they’re backed by the best 25-year Combined Power and Product Warranty in the industry. Why are we so confident? Because only 1-in-20,000 SunPower panels are returned under warranty.5

You can own the most efficient solar panels available for purchase today

The panels SunPower is delivering to our customers are the highest efficiency panels you can buy today, produce the most energy over the long term and, with their sleek all-black appearance, are the most attractive.

Higher efficiency means you’ll need fewer SunPower panels on your roof to generate the same amount of power, or more, than you would generate with a conventional system. And, with fewer panels, you may even have room to expand your system should your energy needs increase.

If you’re waiting for solar panel efficiency to improve before you purchase a system, keep in mind that the federal government offers a 30 percent solar investment tax credit to qualified U.S. solar customers,6 but the incentive is set to expire at the end of 2016. That’s a good reason why it’s best not to postpone going solar. Talk to us about financing if you’re unsure.

SunPower is proud to be the leader in offering the highest efficiency commercially available solar panels1 to customers today and in continuing to innovate relentlessly.

1 To be published in Progress in Photovoltaics, Solar Efficiency Tables v47. As measured by National Renewable Energy Laboratory, Test report #2K1545. Module aperture area = area inside the frame = 1.57389 m2

2 Green, et. al. Solar Cell Efficiency Tables (Version 46), PiP 2015; 23:805–812, 2015. As verified by the U.S. Department of Energy’s National Renewable Energy Laboratory.

3 SunPower 345W panel vs. Conventional Panel (250W, 15.3% efficient, approx. 1.6 m2)

4 Hasselbrink, E., et al. "Validation of the PVLife Model Against 3 Million Module-Years of Live Site Data." 39th IEEE PVSC, Tampa Florida, 2013.

5 Most energy per rated watt compared to the top ten solar manufacturers (9 of the top 10 manufacturers were tested, based on Photon Consulting 2013, Silicon module shipments). Photon International, 2012 and 2014.

6 Tax credits subject to change. SunPower does not warrant, guarantee or otherwise advise its partners or customers about specific tax outcomes. Consult your tax advisor regarding the solar tax credit and how it applies to your specific circumstances. Please visit the dsireusa.org website for detailed solar policy information.

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