Degradation rate is the annual percentage drop in a panel's power output as materials age under UV, heat and thermal cycling. Australian warranties often guarantee about 80–92% output by year 25 depending on brand and technology. Understanding degradation keeps payback models honest and explains why performance warranties differ from product warranties.
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Many modules quote roughly 0.25–0.55% per year after a first-year light-induced drop. N-type technologies sometimes advertise lower fade. Treat brochure curves as commitments only to the extent the warranty enforces them.
Light-induced degradation can step output down early. Quality manufacturers characterise and warrant that step. Ultra-cheap unmarked panels with vague curves are a risk on long Australian roofs.
High UV, coastal salt, inland heat and storm cycling all influence real fade and failure modes. Installation quality (clamping, cable management) often decides whether panels reach their warranted curve.
Year-1 savings are not year-20 savings. A conservative model applies the warranted degradation curve and includes an inverter replacement. That sobriety is how you avoid disappointment.
STCs deem a block of generation upfront based on scheme rules — they are not a guarantee of your personal fade rate. System quality still determines whether your roof delivers.
Ask for the performance warranty schedule and degradation graph. CEC-accredited installers via MrSolar should supply datasheets and explain claim processes if output falls below warrantied levels.
Buy panels with transparent fade curves — compare CEC-accredited quotes on MrSolar.
Written and reviewed by Daniel (Marketplace lead, Epic Unicorn Pty Ltd). We build pages from Australian solar datasets and regulatory references, then map you to CEC-accredited installers only.
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