• Selecting solar panels, as with many other products, comes down to the classic balance of quality vs. cost. Also like any other product, you get for what you pay for. With solar, a higher quality solar panel, like those made by SunPower, may cost a bit more, but the difference in quality can be dramatic. Some installers, who don’t qualify to sell SunPower panels may try to say there isn’t a difference between SunPower panels and other, less expensive panels. So, what many homeowners end up wondering, and what we will explore in this article, is: Are SunPower solar panels worth it?

    First, let’s explore the standards by which people define a ‘quality’ solar panel. People expect solar panels, like any product, to function well, over an extended period of time, and not easily break or otherwise stop working. So, for solar panels, you can translate those expectations into three technical categories: 1) efficiency (the ability to produce electricity); 2) lifetime output rate vs degradation (how long over their lifetime panels will produce a certain amount of power), and durability (the ability to withstand the elements without failing). Through white papers and technical specifications, we can easily compare SunPower with other panels, to see how each of them stand up to these metrics.  


  • Efficiency Comparison

    With solar panels, the most important factor that determines the value of the panel is how well it turns sunlight into electricity or its efficiency. Technically, the efficiency of a solar panel is based on the percentage of sunlight it can convert into direct current electricity, usually in the range of 10-20% for most panels. The higher the percentage, the better the efficiency and the more power a panel will produce given the same amount of sunlight.

    When installed on your rooftop, however, efficiency usually translates into how much power can be produced per square foot of solar panel (that is, per square foot of rooftop). So, the more efficient the panel is, the more power (expressed in watts) it will produce in the same amount of space with the same amount of sunlight.

    For this reason, efficiency can have big implications when it comes to rooftop solar installations when trying to produce enough electricity over the course of a year to zero-out the building’s electricity needs.

    For instance, some commercial buildings may have a large amount of rooftop space available compared to the amount of power they need – and therefore can afford to install less efficient and less expensive solar panels (which take up much more space). Conversely, most homes provide a more limited amount of roof space, so choosing the most efficient available often makes a lot of sense because making the most out of the space available is the key to minimizing the monthly power bill.

    So now that its’ clear why more efficient solar panels make sense, let’s compare the efficiencies of the top solar panels from the top manufacturers, including SunPower, to see how they stack up.


  • Panel Comparison

    ModuleDC Rating (W)EfficiencySize (sq ft)Power/sq ftAdvantage
    SPR 37037022.7%17.5421.111% Higher!
    LG 36036020.8%18.5919
    Pana 34034020.3%18.0219
  • The SunPower 370 AC Panel: 22.7%

    The LG Neon 360: 20.8%

    The Panasonic N340 HIT+: 20.3%

    So as you can see, out of the top solar panels from the top solar panel companies, the SunPower 370 comes in at a whole 2% more efficient than the competition. That may not seem like much, but solar panel efficiencies increase very incrementally over time, so 2% is actually a big gap. So when it comes to efficiency, SunPower easily takes the cake.


  • Lifetime Output Rate (or Degradation) Comparison

    The second biggest factor that determines the quality of a solar panel is the lifetime output rate (or degradation rate). All solar panels will gradually produce less power over their 25-30 year lifetime and the degradation rate is the measurement of how quickly this will happen.

    Over the past 10-15 years, all solar panels makers have managed to not only lower the cost of solar panels (based in dollars per watt), they have also been able to improve the efficiency (above) and also improved lifetime output rate (i.e., lowered the degradation rate) so that panels will hold their efficiency longer over their lifetimes. This translates into more power being produced over more years for the price paid.

    In fact, most of the reputable solar panels manufacturers will also guarantee (warranty) that their solar panels will NOT lose power any faster than the guaranteed degradation rate.

    So, let’s take a look at the average degradation rates warranted by the solar manufacturers we have already looked at, to see which one will save you the most money, and therefore provide the most value over time.

    SunPower Panels: Degrade at .2% per year (based on this study)

    Panasonic Panels: Degrade at .26% per year (based on Panasonic’s calculations)

    LG Panels: Degrade at .4% per year (based on LG’s calculations)

    So, there you have it. SunPower solar panels degrade the slowest (and the least amount over their lifetime), according to a very recent study. If you combine the higher efficiency of SunPower panels with the fact that they degrade much more slowly, you will realize that the total amount of power produced over 5,10 and 15 years starts to really add up to a big difference. We should also point out that the cheapest panels on the market often produce fairly well for 5-7 years and then their output drops off a cliff and they can lose up to 50% or more of their rated power output in the second half of their lifetimes – and that’s when big power bills come back!


  • Durability Comparison

    Like any product, you want your solar panels to stand up to the elements. Given that solar panels sit on rooftops, they are especially susceptible to environmental factors, so this is an even more important factor when it comes to solar. High wind, temperature fluctuations, weight from snowfall, rain, etc. all can affect solar panels, so knowing that your panels can stand up to these elements will guarantee your production and therefore, your peace of mind. So let’s take a look at operating temperatures, max load from snow and wind, and impact resistance of the top three manufacturers to find out which panel is the most durable.

    SunPower 370:

    Operating Temp: -40˚ to +149˚

    Wind and Snow Resistance: 125 psf (pounds per square foot)

    Impact Resistance: 1 inch diameter hail at 52mph

    Panasonic N340:

    Operating Temp: -40˚ to +185˚

    Wind and Snow Resistance: 112 psf

    Impact Resistance:  1 inch diameter hail at 52mph 

    LG NeONR:

    Operating Temp:-40˚ to +194˚

    Wind and Snow Resistance: 125 psf

    So you can see here that mostly, these panels rate similarly in durability. So, not much difference here. But it’s good to know that there is a standard in the industry, and that most panels will stand up to the elements.

    So if you do the comparison, the main differences in panel models lie in the efficiency and degradation. SunPower clearly takes the cake in these categories, creating more power for longer. There are other factors that may or may not deter a buyer from a certain company, like solar aesthetics, but really, you’re paying for the solar to produce, and when it comes to that category, SunPower takes the cake by far. So when you’re considering what solar panels to go with, keep in mind that SunPower will make the most power for longer, powering your home for longer, and saving you more on your electric bill than any other panel.


  • 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.