Glossary
Degradation
Degradation is the slow, predictable loss of a solar panel's production capacity over its useful life, expressed as a percentage per year. Each manufacturer states it in its production warranty (how much the panel yields in year 25). A serious proposal builds it into the savings projection; one that does not inflates the later-year numbers.
What degradation is
A new panel produces close to its rated power. Over time, sun exposure, heat and temperature cycling reduce that capacity a little each year. It is not a defect: it is the normal aging of silicon and the materials that encapsulate it. In good-quality monocrystalline panels it is a small fraction of a percent per year; the exact figure is stated by the manufacturer.
There is an additional first-year effect (sometimes called LID, light-induced degradation) somewhat larger than the following years, which is also usually covered in the warranty.
Why it matters in Florida
Florida’s heat and humidity speed up the aging of any material, and panels are no exception. That is why two spec sheet numbers matter: the guaranteed annual degradation and the temperature coefficient. A panel that degrades faster produces fewer kWh in year 15 and, if the system was sized at exactly 100%, stops covering your usage sooner than planned.
With a subscription, that risk is not yours: if the system produces less than the written annual minimum, you get back the equivalent percentage of the payment.
Common mistake
Accepting a 25-year projection where production is the same every year. Any serious proposal shows a declining curve. Compare the degradation the proposal assumes with what the manufacturer guarantees; if the proposal is more optimistic than the warranty, the projected savings are inflated. How to read that section is in solar panel types and warranties.
Full guide: Solar panel types and warranties: what to ask for and what to ignore →
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