Solar panels are sold with twenty-five year warranties, which sounds reassuring and is frequently misunderstood. There are actually two separate warranties on a panel, plus a third on your inverter, and knowing the difference tells you what you are really buying.
The performance warranty is the twenty-five year one. It does not promise the panel will work for twenty-five years; it promises the panel will still produce at least a specified percentage of its rated output at various points. Typically something like ninety per cent at year ten and eighty to eighty-five per cent at year twenty-five, though exact figures vary by manufacturer. Panels degrade slowly, and this warranty covers degradation faster than the stated curve.
The product warranty is much shorter, commonly ten to twelve years. This covers manufacturing defects, delamination, and physical failure. If a panel actually fails rather than merely underperforms, this is the warranty that applies.
The inverter warranty is shorter still, commonly five to ten years. This matters because the inverter is the component most likely to need replacement during the system's life, typically somewhere around year ten to twelve. Budget for this replacement rather than treating it as an unexpected failure. A good installer will tell you this upfront; a poor one leaves you to discover it.
Then there is the installer's own workmanship warranty, which is separate from all three manufacturer warranties and varies enormously. This covers the mounting, cabling, earthing and general quality of the installation. Ask what it covers and for how long, because in practice a substantial share of solar problems are installation problems rather than component failures.
What warranties do not cover, generally. Damage from extreme weather beyond specified limits, damage from improper cleaning, and performance loss from soiling. That last one matters in Delhi NCR, where dust and pollution reduce output meaningfully between cleanings. A dirty panel producing less is not a warranty claim; it is a maintenance issue.
How to actually claim. Warranty claims run through the manufacturer, usually via your installer. This is one practical reason to prefer an established installer likely to still exist in ten years, and an established panel manufacturer likely to still honour claims. A twenty-five year warranty from a company that closes in year four is worth nothing.
What to check before signing. Get the panel make and model in writing, along with both the performance and product warranty terms. Get the inverter make, model and warranty. Get the installer's workmanship warranty in writing. And confirm the panels are DCR-compliant, since that decides your subsidy entirely.
A realistic expectation of system life. Panels commonly outlast their warranty and continue producing at reduced output well beyond twenty-five years. One inverter replacement in that period is normal. Occasional cleaning is required, more often in NCR than elsewhere. Beyond that, a well-installed rooftop system is a genuinely low-maintenance asset, which is a large part of why the economics work.
The summary. Twenty-five years refers to performance degradation, not to the whole system running untouched. Plan for an inverter replacement, budget for cleaning, and choose an installer and manufacturer who will plausibly still be around to honour what they have written.
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Last updated 27 July 2026 · Reviewed by the RenSetu team