• There’s no doubt that, thanks to their electric vehicle success, the Tesla brand has become ubiquitous. When Tesla owner Elon Musk purchased SolarCity in August 2016 for $2.6 billion, the Tesla magic subsequently became associated with “Tesla Solar.” Unfortunately since then, the company’s rank (based on number of U.S. solar installations) has fallen from #1 to #3 so the magic may not translate to new industries. But folks who are researching solar for their homes are naturally asking, when it comes to product performance and value, how does a large company like Tesla (with many different products)  stack up against a company like SunPower, which has exclusively specialized in solar energy systems? To answer, let’s take a look at solar panel quality, warranty, and track record to see how these two solar companies stack up.

    Tesla Solar Roof Tiles vs. Tesla Solar Panels

    But first, we should  address the difference between “Tesla solar roof tiles” and “Tesla solar panels.” Tesla has gained a lot of attention from its claim to be reinventing solar by incorporating the solar cell into the roofing material itself, calling this new product a "solar roof." However, while this sounds good in theory, the company has not yet had much success in rolling this out in real life.

    The issues with the Tesla solar roof tiles continue to plague the company’s efforts. The problems include: 1) very small production number beyond their test houses; 2) higher than expected installation costs which makes the solar roof cost not very competitive with traditional solar panels; and 3) long-term durability issues because water and electricity does not mix and protecting the electrical connections between tiles over time has proven to be problematic. So since the Tesla solar roof tiles have been realized to not be a legitimate solar solution for the foreseeable future, for the sake of this article, we will be discussing Tesla Solar panels, and not solar roof tiles. 

    SunPower vs. Tesla Solar Panels

    SunPower solar panels are known to be the most efficient panels on the market, especially now with the recent release of their 415 watt panel with it’s record breaking 22.3% efficiency. They’re also known to be the most durable panel on the market, with a longer useful life than any other panels, which means they produce more power for longer. They also boast the most comprehensive and all-encompassing warranty of any panel on the market, assuring that the panels will work better for longer. 

    So, we know that SunPower panels are top of the line, but what do we know about Tesla solar panels? Well, what we do know is that Tesla does not manufacture their own panels. According to their website, the company currently installs Hanwha 315 watt Q-Cell Panels. So let’s do a comparison of the new SunPower 415 with the Hanwha 315 to see how they compare.

  • Efficiency Comparison

    Obviously, the most important aspect to any solar panel is how much power it can produce. This is known as ‘efficiency’ and is measured by power output and efficiency. Here is how the Hanwha 315 and the SunPower 415 stack up:

  • ModelHanwha 315SunPower 415
    Rated Power315W415W
  • For those that don’t know, ‘rated power’ is a panels output under ideal testing conditions, measured in watts. Clearly the SunPower 415, with 415 watts of output, is superior to the Hanwha 315 in its electric production potential. This means that the SunPower 415 can produce more power given the same conditions as the Hanwha 315.

    Solar panel efficiency, measured in percentages, is the amount of sunlight that the panel can turn into usable electricity. So in comparing the Hanwha 315 and SunPower 415, the SunPower 415 produces 3.6% more power than the 315 given the same amount of sunlight. If you consider that percentage increase of the course of a day, month, and year, you can see that the amount of power that the SunPower 415 creates a substantial amount more power given the same conditions, which means that homeowners can produce more power with the same amount of roof space, or produce the same amount of power with fewer panels.

    Degradation Rate

    The power degradation rate of a solar panel is the rate at which a panel loses its production efficiency over time. There are two types of solar panel degradation. The first is what is referred to as LID degradation, or “light-induced degradation”, and it is caused by a chemical reaction that occurs when sunlight first strikes the new solar panel. Most solar panels experience at least 2-3% LID degradation in the first few weeks of operation; not so with SunPower panels, which experience zero LID degradation due to their unique cell composition. So, if all other numbers are equal, SunPower panels will produce 2-3% more power than the competition, right out of the starting gate.

    The other type of power degradation is one that occurs slowly over time. All solar panels experience some degree of degradation over their lifetime, but some more than others. Part of a panels’ warranty is usually a guaranteed minimum output after the end of a certain period. Let’s look at the guaranteed minimum output of both the Hanwha 315 and SunPower 315.

  • ModelHanwha 315SunPower 415
    Output Warranty Term25 years25 years
    Minimum Output at End of Warranty85% of Rated Power92% of Rated Power
    Maximum Annual DeclineYears 2 to 25: Less than 0.54%Years 2 to 25: 0.25%
  • So as you can see, the SunPower 415 has a lower degradation rate than the Hanwha 315. This  results in a significant difference in power production (and therefore savings); in fact, SunPower estimates that its panels will produce 60% more power over their lifetime than standard industry solar panels.

    SunPower Vs. Tesla Warranty

    Besides protecting customers from dramatic power output “drop-off” early in the lifetime of the solar panel (the solar production warranty), a second part of the warranty covers the length of time the solar panel will be repaired or replaced with no cost if it should stop working completely; this is called the “product warranty.” Obviously, if the solar panel’s lifetime is 25 years, you would expect that the solar panel’s product warranty would also be 25 years, right? Unfortunately, the Hanwha panels used by Tesla are even covered for half of that time!

  • ProductSunPowerHanwha
    Panel25 years12 years
    Inverter25 years10 years
    Racking25 years N/A
    Monitoring10 yearsN/A
  • So as you can see, SunPower’s product warranty is much longer than Hanwha’s. That means if anything goes wrong with your Hanwha system after the 12-year mark, you will need to pay for the repairs, unlike with the SunPower system. 

    Tesla Vs SunPower Panel Aesthetics

    Most homeowners care about how their panels will look on their roof, which is why another factor that has to be considered when comparing solar panels is solar aesthetics. There are many features of a solar panel system that can determine its overall aesthetic appeal, including the cell, the panel backsheet, the frame, the racking system, and size. SunPower is known for creating the sleekest and most visually appealing solar panels on the market. Let’s look at why. 

    Below is a picture of the Hanwha 315 and the SunPower 415 side by side.

  • While these panels look mostly similar with a black frame and white backsheet, if you look closely you can see that the Hanwha panel has small lines within each cell. That look is called “wired” and is typically seen as a negative when it comes to solar panel aesthetics. If you look at the SunPower 415, you can see that those cells don’t have it. That’s because the wireless cell look is exclusive to SunPower, and is actually a patent of theirs. So that clean, flat black cell is something you will only see with SunPower panels.

    So there you have it, the differences between SunPower and Tesla solar. SunPower boasts the most powerful panels on the planet, with the lowest degradation rate, longest warranty, and best aesthetics. Tesla uses inefficient panels, with a short warranty, high degradation rate, and “wired cell” appearance. SunPower has superior customer service and a network of highly qualified service techs, Tesla makes great electric vehicles. We think you can make your own decision based on this information. Just remember, your solar system will be on your home for 25+ years, so what company you choose will decide how your solar experience is for decades to come.

  • About the Author

    Michael Powers


    Michael is one of the founding partners of Stellar Solar. In 2001, he helped launch The Home Depot’s national solar energy program which is now offering home solar through hundreds of stores in nearly a dozen states. He is a writer and marketing professional with over 30 years’ experience in the fields of energy, market intelligence and leadership training. He currently serves as treasurer and board member of Global Energy Network Institute (GENI), a San Diego-based non-governmental organization that advocates linking renewable energy resources around the world using electricity transmission.