The industry benchmark for solar panel lifespan is 25 to 30 years. However, after 25 to 30 years, a solar panel's power output will significantly decline below what the manufacturer predicted. It isn't easy to estimate the upfront cost of adopting solar without knowing how long your rooftop panels will provide sufficient energy. Solar panels will eventually balance your electricity consumption for decades and greatly lower your energy bills. Still, it's vital to understand industry estimates and degradation rates to determine when you'll need to replace your system.

How long do solar panels last?
The average lifespan of solar panels is approximately 25 to 30 years. However, this does not mean that they cease producing electricity after 25 years; it simply indicates that energy production has decreased significantly. In the absence of physical damage from extreme weather, wind, debris, or other external factors, solar panels (also known as solar modules) will continue to function for many decades. This is primarily due to the absence of moving elements in solar panels, typically only destroyed by external factors like improper rack installation or severe weather.

How quickly do solar panels degrade?
The National Renewable Energy Laboratory (NREL) discovered in 2012 that average solar panel output declines by 0.8% annually. This falling rate is known as the solar panel degradation rate. This measure varies depending on the brand of solar panel you choose. However, premium manufacturers such as SunPower provide degradation rates as low as 0.3%. As solar panel technology advances over time, degradation rates continue to decrease, and degradation rates of 1% are increasingly commonplace in the industry. More efficient technologies have been developed since this 2012 study was completed, and the energy production of many modern panels has decreased by barely 0.5% each year (or better!).

What precisely does the panel degradation rate mean? With a 0.8% degradation rate, your solar panels will provide 99.2% of their original output in year two and 82.5% at the end of their 25-year "useful lifespan." A solar panel with a deterioration rate of 0.5% will likely provide approximately 87.5% as much energy as it did when it was initially installed. To calculate the expected output of your solar panels after a specific number of years, multiply the degradation rate by the desired number of years and deduct 100 from the result.

Solar panel guarantees: what to understand.
In addition, solar panels come with various warranties that might give you an idea of how long you can anticipate your solar panel to last. Your manufacturer's warranty will include an equipment warranty covering manufacturing faults and a performance (or power) warranty, ensuring that your solar panels will generate a particular quantity of electricity. Notably, faults outside the manufacturer's control (such as damage caused by falling tree branches) are often not covered under warranty.

To determine your solar panels' expected rate of depreciation, you should examine the performance warranty. Typically, a performance warranty lasts 25 years and guarantees that your solar panels will maintain a set percentage of their initial production annually. Here is a summary of some of the best performance warranties offered by QuestGreens solar panel manufacturers:

Can you make your solar panels survive longer?
In general, solar panels are quite resilient. Most manufacturers test their panels to guarantee they can endure severe winds and large snow loads, and many solar panels undergo additional testing to verify that they can handle hail. In addition, solar energy systems typically lack moving parts and require minimal maintenance. However, maintaining your solar panel system might decrease the annual degradation rate and offer longer panel performance. Here are some steps you may take to extend the life of your solar panels:

1. Select a respected installer and durable equipment
Working with a reliable installer who provides excellent customer service and a labor warranty is the best way to ensure that your solar panels continue to function over the long run. As previously mentioned, it is also crucial to get high-quality solar panels with substantial warranties - to preserve your solar investment; you'll want to ensure that the maker of your solar panels assures you that they will be free of flaws and function effectively for a long time.

2. Have an installer evaluate your solar panels routinely
To preserve the longevity of your solar panels, have your installer or operations, and maintenance (O&M) provider do routine inspections of your solar panel system. Frequent maintenance inspections can identify potential issues such as open shelving, exposed wiring, and other problem areas. It is vital to have a professional inspect your panels instead of doing it yourself, as you can void the guarantee on your panels if you scratch or otherwise damage them.

In addition to inspecting your solar panels, your roof rack system and inverters may also be inspected during a solar panel check. A typical central inverter for a photovoltaic (PV) installation will last between 10 and 15 years and will thus need to be changed during the lifetime of your solar panels. Nevertheless, microinverters typically have the same 25-year lifespan as their solar panel equivalents. When it comes to racking, it is always necessary to ensure that your solar panels are attached firmly to your roof so that they do not get loose and shift or fall off.

3. Safeguard your solar panels from harm
When your solar panels are first installed, your installer will ensure that there are no large trees nearby that could throw shade or drop branches on the panels. So long as you prevent physical damage to your solar panels, they will continue to provide electricity for many years, possibly well beyond the normal 25 to 30-year "lifetime" of solar panels. You can also purchase products designed to prevent particular physical harm to your panels. For instance, solar panel critter guards can prevent animals, such as squirrels and birds, from nesting beneath your panels, which can result in panel and wiring damage over time.