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What Is The Efficiency You Can Expect From Standard And Premium Solar Panels?


Standard solar panels are around 15-16% efficient. Our most popular solar panel brand that we sell is Canadian Solar, which is just a touch more than 16% efficient according to its official data sheet. Some solar panels have a higher level of efficiency, even approaching 23%. In fact, the SunPower panel model X22 series are 22.8% efficient as measured this past February. A higher efficiency panel means that you will be generating more electricity. Premium panels are more technologically efficient and the cost structure reflects that extra efficiency.  

The questions we need to ask are whether the extra cost is financially worth the investment and what other advantages do you receive upon purchase?

We first take a look at the three most popular panels that we sell: Canadian Solar, SolarWorld, and SunPower. Here are a list of their efficiencies and our cost structures:



Cost Per Watt

Canadian Solar CS6P-265P



SolarWorld Plus SW 285 Mono Black



SunPower E20 Series




The numbers we listed are based on each model's product data sheet information. SolarWorld panels generate around 1.25% more energy than Canadian Solar while SunPower generates 21.5% more energy than Canadian Solar. SunPower's E20 series panels cost more than a dollar more per watt than the other two models. If a customer purchases a 7 kW system, that means they will be spending $7,000 more for their system with SunPower in comparison to the other two models. The higher the efficiency of the panels, the more they cost. 

So is SunPower's added efficiency worth the extra cost? The answer is a little more involved. First, we can tell you that SunPower is the Rolls Royce of solar panels. They have an unprecedented 25-year manufacturer's warranty to go along with their 25-year power performance warranty. The standard warranty in the industry is a 10-year manufacturer's warranty and a 25-year power performance warranty. This manufacturer's warranty is part of the reason why they cost more.

SunPower panels have a lower failure rate than standard panels. The company claims that their manufacturing design eliminates 85% of the reasons conventional solar cells fail. The main problems that usually occur with conventional panels are that the frame can be loose and let moisture seep in, or potential induced degradation can occur where the cells react with the aluminum frame that can lead to cell failure, or cell interconnect breakage can take place where the bus wiring and junction box on the back of the panels have a defect. These problems have been greatly reduced by SunPower's superior manufacturing process. They are simply better made panels that are guaranteed to last longer.

We generally tell customers that the majority of their panels (not all, but a majority) will last 35-40 years into the future after purchase. It is impossible to determine what percentage will be around with any type of accuracy since the industry is only around ten years old. However, we have a higher level of confidence in SunPower's panels lasting further off into the future after the power performance warranty runs out simply due to their higher standard of manufacturing. The manufacturer's warranty is 15 years longer than the industry standard and we think that more of their panels will last longer without experiencing failure than any other brand to go along with the higher level of efficiency. Over a long enough timeline, higher efficiency panels that last longer will eventually surpass standard model panels in terms of ROI. Long-term investors are more likely to purchase SunPower and other high efficiency modules to take advantage of better production as well as not worrying about panel durability.

We also know that if you are purchasing a higher efficiency panel you will need fewer panels to create your desired electricity offset. As an example, if you wanted to offset approximately 85% of the average family's electricity bill per month with a 7 kW system, you would need around 27 panels of the Canadian Solar model whereas with SunPower you would only need around 22 panels. For roofs where there is limited space it can sometimes be the best option to achieve the offset you want.

Finally, some people simply want the highest performing technology on the market, regardless of price. And they are willing to pay for the best.   

So What Type Of Pricing Are You Looking At For A Premium Panel System?

The average cost per watt of solar in 2016 in America is around $3.70 per watt for a 5 kW system before the 30% Federal Tax Credit as per Energy Sage. That includes an average of standard panels as well as premium panels. The price per watt of a residential solar power system decreases the bigger the system that you design and install due to the fixed costs involved. YellowLite's pricing is lower than the national average at around $3.50 per watt for a 5 kW array. If a customer goes up to a 10 kW array, we are generally pricing the system at around $3.20 a watt for standard panels. For a smaller array, it is a higher price per watt based on having more emphasis on the fixed costs of project development.

The cost of premium panels using SunPower for a 5 kW array is around $5 per watt and decreases to $4.50 per watt for a 10 kW array.


Premium panels do cost more than standard panels initially. However, you also have to consider a few factors before purchase in order to make a value comparison. You will need to purchase fewer premium panels than standard for your array when you go to install based on higher efficiency. Premium panels also come with a longer and more extensive manufacturer's warranty, so you have a longer time frame to be covered in the event that something goes wrong. This peace of mind is important for a lot of investors. Premium panels are also thought to last for longer into the future beyond the manufacturing warranty without wearing out due to their higher durability, so the real cost advantage is in the years of production that will be expected several decades into the future. Because of these reasons, premium panels can offer a substantial value proposition over the life of your solar energy system. That value will not be as pronounced in the first few years of owning your system, but will eventually be seen over the system's lifespan. 

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