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How Long Do Solar Panels Last?


One of the most common questions we hear from homeowners considering a solar panel installation is “how long do solar panels last?” It’s hard to understand the upfront cost of going solar without knowing how long you can expect your rooftop panels to produce ample energy. Your solar panels will be able to offset your electricity use for decades, but it is also important to understand industry projections and degradation rates. 

How Long Do Solar Panels Last?


In general, the rule of thumb, solar panels can last about 25-30 years. However, this doesn’t mean that they stop producing electricity after 25 years – it just means that energy production has declined by what manufacturers consider to be a significant amount. Solar panels can continue to work for many decades, given they aren’t physically damaged by wind, debris, or any other external factors. This is primarily because solar panels don’t have any moving parts – they rarely break from within and are usually only damaged by outside forces like a poor racking setup or inclement weather.


Solar Panel Degradation Rate


A 2012 study by the National Renewable Energy Laboratory (NREL) found that, on average, solar panel output falls by 0.8% each year. This rate of decline is called solar panel degradation rate. Though this rate of decline metric will vary depending on which panel brand you buy, premium manufacturers like SunPower offer degradation rates as low as 0.3%. Solar panel degradation rates are constantly improving as solar panel technology gets better over the years, and degradation rates below 1% are common throughout the industry. In the years since this 2012 study was conducted, more efficient technologies have been developed and many newer panels have just a 0.5% yearly decline in energy output.


What does panel degradation rate mean exactly? For the above example, a 0.8% degradation rate means that in year 2, your panels will operate at 99.2% of their original output; by the end of their 25-year “useful lifespan,” they will still be operating at 82.5%. A slightly more durable panel with a degradation rate of 0.5% will likely produce around 87.5% as much electricity as it did when it was first installed. To determine the projected output of your solar panels after a certain number of years, you can simply multiply the degradation rate by the number of years you are interested in and subtract that number from 100%.


Solar panels also come with a few different warranties that can give you a sense of just how long you can expect your solar panel’s lifespan to be. Manufacturers will offer both a product warranty, to certify against manufacturing defects, and a performance warranty, to guarantee that your panels will produce a certain amount of electricity. Your solar panel’s performance warranty, which typically lasts 25 years, can give you a better sense of how much electricity to expect from your solar panel system over time.


You don’t need to worry about the carbon footprint of your solar panels, either. The 25 to 30 years lifespan of a solar panel is significantly longer than its “energy payback time,” or EPBT. EPBT is the amount of time it takes for a solar panel to produce enough clean electricity to “pay back” the energy that was used to manufacture it in the first place. A 2010 analysis from Brookhaven National Laboratory found that the EPBT of a solar panel is just 6 months – a number that has surely fallen in the past 6 years as panel manufacturing becomes more efficient.


Can You Make Solar Panels Last Longer?


In general, solar panels are extremely durable. Most manufacturers test their panels to confirm that they can withstand high winds and heavy snow loads, and many solar panels are specifically tested to ensure that they can withstand falling hail. Additionally, solar energy systems don’t usually have moving parts, and they require little to no maintenance.