Although the general answer to this question is 25 to 30 years, that isn’t really correct. In actuality, we’ve seen solar panels that were installed at sites over 40 years ago that are still producing a significant amount of energy. The main issue is that solar panels have a certain amount of energy degradation (loss of energy production) over time. Typically, the amount they degrade (produce less electricity) is somewhere around .3% to .8% range per year. With regular maintenance of the solar panels, however, and choosing a top of the line solar panel manufacturer, it’s possible for solar panels to last for much longer than the generally stated 25 to 30 years. For example, both Sunpower and Panasonic, two of the top solar panel manufacturers, have 25-year warranties on their panels that guarantee the panels will produce 90% AC/ 92% DC power output at the end of year 25. Solar panels can last more than 30 years if you choose a high quality solar panel and do regular maintenance and cleaning on the system.
