Quick Answer
Short Answer: Replace solar panels under warranty when their efficiency drops below 80% or their maximum power output (Peak Power) falls 10-15% below the manufacturer's specified rating, which is usually around 5-7 years from installation.
Assessing Panel Performance
When evaluating solar panel performance, it’s essential to check their efficiency and power output. Most solar panels guarantee an 80% efficiency rate for 10 years and a 90% efficiency rate for 5 years. To assess your panels’ performance, measure their actual power output with a wattmeter. Compare this to the manufacturer’s specifications and your initial system design calculations. If the difference exceeds 10-15%, it may be time to consider replacing your panels.
Manufacturer Guidelines
Check your solar panel warranty documentation for specific replacement guidelines. Many manufacturers, like SunPower and LG, have pre-defined replacement criteria based on a percentage drop in efficiency or power output. Typically, these criteria are as follows: For SunPower, panels with a 10% drop in efficiency are eligible for replacement after 10 years; for LG panels, a 5% drop in efficiency is grounds for replacement after 12 years. Research your manufacturer’s specific guidelines to determine the best course of action.
Roof Mount Considerations
When replacing solar panels, don’t forget to inspect and maintain the roof mount. Corrosion, sagging, or other damage to the roof mount can lead to further issues with your system’s performance and safety. Inspect the roof mount for any signs of damage, and replace it if necessary. Consider upgrading to a more durable or secure roof mount design to ensure your new panels last for decades to come.
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