I'm trying to decide between two solar panel options: the Panasonic 420W and the Hyundai 440NF. The Panasonic offers 22.2% efficiency with a guarantee of 92% power output over 25 years, while the Hyundai claims an 87.4% power output guarantee for 30 years. The production difference is that Panasonic makes 420W panels, while Hyundai produces 440W ones. The Panasonic panels are more expensive, but they seem to be the more popular choice. Considering the differences in output guarantees, how significant is that to overall performance? If both panels had similar costs (the price difference for a 15-panel system is about $1.5k before credits), which one would you pick?
2 Answers
Honestly, I think it’s best to go for the cheaper option when looking at cost per watt. Most likely, you’ll want to replace your solar panels after 10-15 years anyway. So, save some cash now!
I’d lean towards the Hyundai since it’s cheaper. Even though they might degrade more quickly, you start with a higher output. After 25 years, you’d still be ahead performance-wise, even accounting for degradation.
This makes sense, but can you clarify how that works? If there’s an 8% decrease over 25 years, wouldn't that total around 9.6% loss at 30 years, which seems worse than 87.4%?
Why would I need to replace them so soon?