• The Solar Quote

How Long Do Solar Panels Last?

Updated: Mar 9, 2019



While great improvements to solar technology have been made in recent years, a common concern among many potential customers is "How long do solar panels last?" You might be surprised by the longevity that today's solar products offer.


In the article below, we'll provide you with a more detailed answer by discussing some of the things that can influence the average lifespan of solar panels. Understanding the points touched on below will allow you to make an educated decision on what to look for in these types of products and determine what might be a good fit for your business or home.


Solar Panel Longevity


For those of you who may need a quick refresher on how solar panels work or what potential they may have, the video below should get you back on track quickly. No matter what level of understanding you have it is important to keep in mind that there are many things that can influence the average lifespan of solar panels.



Like any other equipment, solar panels will begin to degrade and wear out over time. So, when asking "How often do you have to replace solar panels," make sure you take into account some of these issues:


Damp Heat - Dampness is a natural product of the environment, and when that dampness also generates heat within the enclosure it can deteriorate components. The cells can begin to experience corrosion and encapsulants may become delaminated.


Humidity Freeze - Humidity will build up in your equipment, especially during certain times of the year. When it freezes it may cause adhesion to fail, for example, at the junction box.


Thermal Cycling - Many outdoor settings experience extreme temperature changes during certain months of the year. The temperature cycling between the highs and lows can wear on the solder points or on the solar cells.


UV Exposure - Between visible and X-ray light, the sun generates ultraviolet light. UV light will degrade the back sheeting as well as cause discoloration of transparent materials.


The extent of possible damage over time from one or more of the sources listed above will vary depending upon location, maintenance, and protection. The National Renewable Energy Laboratory (NREL) notes that these factors are unavoidable in outdoor settings and make it difficult to pinpoint an exact window for the average lifespan of solar panels. It is worth noting that SunPower panels carry a 25 year warranty so, if anything were to go wrong during that period, you're completely covered. And by that time, your panels have paid for themselves several times over.


Do solar panels go bad for other reasons?


Damage and degradation can be caused by other natural phenomena, including damage from extreme weather such as large hail, high winds, or even scratching from moving tree limbs.


Less expensive products may save you money by using less aluminum for the housing, making them less durable overall while allowing the elements to affect them more. These cheaper products may not use the latest materials which provide greater longevity than compounds used even a decade ago. Also, neglect will often shorten the length of time solar cells operate at their best. Solar panels are very low maintenance but you do want to keep them clean.


Determining Industry Standards


In today's solar market, industry standards base how long do solar panels last on a study that came out in 2012 from the National Renewable Energy Laboratory (NREL). Due to the results found in this study, you will notice that solar panels are offered with a performance warranty of 25 to 30-years.


Does that mean that you need to replace your panels after the 25 to 30-year window covered by the warranty? Not necessarily. The panels will still produce electricity after this time period, it simply means that your solar panels are past their "useful lifespan" and will generate noticeably less energy then they did when they were new. Read on to see the level of degradation.


How Is Degradation Measured?


The rate of your product's decline is measured by the solar panel degradation rate. This scale is based on the 2012 NREL study and uses an annual degradation rate of 0.8-percent. For example, a one-year-old panel will generate 99.2-percent of its original output, while a 25-year old product will operate at 82.5-percent.


You will want to keep in mind that solar technology has improved since 2012.


Engineering Professor, Dr. Tom Lombardo, noted in his 2014 article (linked below) that the degradation rate for monocrystalline silicon cells was closer to 0.4-percent, having panels generating 92-percent of their original output after 20-years! The materials being used in today's panels can perform even better.


To determine the expected output generated by your solar panels after a certain number of years simply follow these two steps:


  1. Multiply the degradation rate by the year you are interested in

  2. Subtract this number from 100-percent to obtain the output for the panel at that age


Are There Things That You Can Do To Increase Solar Panel Longevity?


You can not only extend the lifetime of your solar panels, but you can also increase their output in many cases by applying some of the following suggestions.

Longevity Starts With Your Purchase


Spending more upfront can help As with all equipment that you purchase, you will often get what you pay for. If you save money at the start with cheaper panels, you will probably end up replacing them sooner. Purchasing solar panels with the latest in solar cell technology can increase their longevity as well as their output.


Look for strong warranties There are two types of warranties you will want to consider when shopping for solar panels. The first is a product warranty and the second is a performance warranty.


A product warranty will cover the equipment itself and protect you from manufacturing flaws. Many companies offer a product warranty of at least 10-years. Some manufacturers provide 12 or even 25-year product warranties, however, and provide you with extra peace of mind.



The performance warranty will vary between manufacturers and product lines, but usually, guarantee 90-percent operation at 10 years and 80-percent at 25 years. You may find better performance warranty numbers with high-end products that use the latest materials in the panel's build.


It is worth noting that if you have your equipment installed by a SunPower, we offer a warranty covering the installation as well. We recommend letting professional contractors install your solar panels in order to prevent problems that may void your product or performance warranty due to installation errors.


Have your panels inspected and serviced regularly Have the company that installed your equipment back to inspect it routinely. They can spot potential issues like loose racking and wire damage caused by animals or the elements. Having this done on a regular schedule every year or two can help to catch a small problem before it becomes a bigger issue.


Professional services are also capable of inspecting other elements of the solar panel system. This can keep your inverters running optimally and make sure that your rack is safely fastened to the roof. As mentioned previously, having a professional contractor perform maintenance on your solar panel system will prevent product and performance warranties from being voided due to accidental damage.


While inverters usually require replacement more often than the panels themselves, severe damage or neglect may require complete panel replacement. Usually, panel repairs consist of broken glass, cracks on the panel, or loose connections. These costs are minimal, consisting of the price of the part in question and labor.


Protect against damage Keeping animals that can damage wires away by installing barriers can help. Trimming trees or removing objects that can possibly scratch your panels will also help. Also, use caution and proper gear (or help from the pros) when cleaning dirt or snow from your solar panels to help prevent any accidental damage to components.

Final Thoughts On Solar Power Longevity


As you can see, how often you have to replace solar panels depends upon many factors. If you purchase through SunPower by The Solar Quote, you're covered by a 25 year warranty on panels, installation and hardware.


Remember that degradation is inevitable but that you can take steps to maintain your equipment at peak performance for decades. Follow the steps listed below to get the most out of your panels, and feel free to comment or ask questions, too!


  • Purchase the best quality panels your budget allows

  • Look for the strongest product and performance warranties available

  • Have them installed professionally

  • Provide professional maintenance on a regular schedule

  • Guard against accidental damage




Links for further reading:

NREL Researchers Discovering Fewer Failures With Equipment Installed Since 2000

Photovoltaic Degradation Rates — An Analytical Review 2012

What Is the Lifespan of a Solar Panel? - Dr. Tom Lombarto (2014)