How long do solar panels last

The short answer – enough to pay off and give free electricity for more than a decade. Read the article to learn what the lifespan of solar panels depend on.
How long do solar panels last? The short answer – quite a while. However, all values are relative. We, humans, have been around in our modern form for some 200,000 years, but it is just a tiny fraction of the Sun’s age. Thus, the longer answer to the question about the lifespan of solar panels would be the following: pretty short in the cosmic scale, but fairly long compared to our lives.

The end of a 25 year warranty is just the beginning

With a rare exception, solar panels out there are designed to function with few signs of degradation for at least 25 years. When this time is over, they are still perfectly usable. The lifespan of solar panels is what makes them a lucrative long-term investment. But how long do PV solar panels last exactly? This article contains the answer to this and some other important questions related to warranty, maintenance and degradation.

80% of power after three decades

As a rule, solar equipment manufacturers guarantee at least 90% of original performance after year ten. After 25 or 30 years you can expect close to 80% of the nameplate capacity. This behavior is closely connected with a phenomenon called degradation rate.

Linear warranty is quite popular among solar companies. It is different from other types in that it states exact performance figures for each year since purchase. It is much better than tiered warranty, because the latter only specifies a single performance number for a very lengthy time period.
Keep in mind that each solar panel has its own warranty, that covers the performance of that particular panel only, not the whole of your system. If you suffer a decrease in energy production during normal weather conditions, your primary suspect should be a faulty panel. This is where the second type of warranty – the product warranty – comes into the picture.

Product warranty: failure-free decade

Product warranty, also known as workmanship or equipment warranty, usually lasts ten to twelve years. It protects the modules against defects in material, quality of assembly problems, malfunctioning and environmental issues. Depending on the brand, the company will either repair or replace the PV modules.

In most cases, costs associated with shipping and human labor to check and replace your equipment are not covered by this type of warranty. However, it doesn’t mean that such warranties don’t exist. To find out these and other warranty details, contact the manufacturer of the product in question.

Keep in mind that the warranty is only good as long as your system is appropriately designed. If some component of your PV system is a poor match, damages that result from this bad choice will not be covered. Thus, it is very important to approach the planning and installation stages responsibly. Repairing and maintenance services performed by an unlicensed electrician will also leave you unprotected. Accidental damages caused are also excluded from the warranty.

Always look at the degradation rate!

PV modules decrease in performance over time. This process is called degradation and it happens at an average rate of 0.8% per year. It means that a current solar panel will produce 8% less energy in ten years.

The numbers vary depending on the technologies and materials: the lower boundary lies at the 0.5% level, while the higher hovers around 1%. Premium brands, including names like SunPower, LG and Panasonic offer products that lose no more than 0.3% of performance annually. This metric has been consistently improving over the years, and the trend will likely continue.
To understand the degradation rate once and for all, let us imagine a standard 250W PV module. Taking the higher 1% rate gives us the following numbers: 247.5W will be left after a year, 245W after two years, 242.5W after three and so on. To find out the power output of your system in a given year, multiply the rate by the number of years since installation and subtract this from 100%. Multiply by the nominal output to convert your result to watts.

Performance warranty deals with the problem of degradation. Alas, it can’t guarantee complete absence of losses during the lifespan of solar panels. This is both due to physical laws and other limitations, such as resistive losses, energy band gaps, etc.

Given the universal character of degradation and other physical processes, it would be strange to ask how long do LG solar panels last, or the panels of any other manufacturer. Solar panels with comparable prices will last about the same, regardless of the manufacturer. Warranty length is the proof – with a rare exception, such as Silfab with its 30 year warranty, solar manufacturers offer 25 year warranties for all their panels.

Double your solar panel’s lifespan with proper maintenance

Hail, snow and even hurricanes – solar panels have the toughness to withstand the harshest weather. This toughness makes them almost maintenance-free, and the absence of moving parts makes repairs a rare occasion.

Although not required, regular maintenance can considerably extend the lifespan of your solar equipment. If you ever wondered how to increase the life of your solar panels, below is a list of recommendations that can make this task easier:
  • Choose a licensed and experienced contractor to establish a maintenance schedule. Thus no problem with your roof, wiring or the panels themselves will escape your view.
  • Make sure all components of your system (battery bank, charge controller, inverters and others) are a good match for one another. They form part of a larger whole, and a glitch in one device may result in damage to the solar panels.
  • Keep the modules clean. Dust particles accumulate on the surface of solar panels. It not only affects the performance, but after a while can also lead to microcracks and scratches on the protective glass. Eventually, this process can lead to serious damage.
  • Of more danger than sand or dust, tree leaves, branches and especially snow need to be removed as soon as possible. The pressure created by the debris’ weight is more likely to harm the panels. Snow, on the other hand, can melt and then freeze, causing temperature-induced microcracks.
The lifespan of solar panels is considerably affected by the regularity and quality of maintenance. Even half a century is not a limit given quality care. If applied diligently, the advice above will extend the time of plentiful solar harvest.
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