Updated: June 2026 | ← Back to Blog
The 25-Year Warranty — What It Actually Means
Every Tier 1 solar panel comes with two warranties: a 10–12 year product warranty (covers manufacturing defects) and a 25-year performance warranty (guarantees minimum output levels). The performance warranty does not mean panels die at year 26 — it means they are guaranteed to still produce at least 80–82% of original capacity at year 25. In practice, most modern panels degrade slower than warranted.
Degradation by Panel Type
| Panel Type | Year 1 Loss | Annual Degradation | Year 25 Output |
|---|---|---|---|
| Polycrystalline | 2.5% | 0.7%/yr | ~80% |
| Mono PERC | 2.0% | 0.55%/yr | ~85% |
| TOPCon (2024+) | 1.0% | 0.40%/yr | ~90% |
What Accelerates Degradation in India
- Potential Induced Degradation (PID): High humidity + high temperature causes voltage leakage. Anti-PID panels and proper earthing mitigate this.
- UV degradation: India's high UV index bleaches EVA encapsulant over years, causing yellowing.
- Thermal cycling: Daily swings between 15°C nights and 45°C afternoons stress solder joints and cell interconnects over decades.
- Soiling and etching: Bird droppings left uncleaned for weeks can permanently etch the glass surface.
Inverter Lifespan — The Weakest Link
Panels last 25–30+ years. The inverter typically needs replacement once during that period:
- String inverter: 10–15 year typical lifespan. Replacement: ₹15,000–40,000.
- Hybrid inverter: 10–12 years. Replacement: ₹35,000–80,000.
- Microinverter (Enphase): 25-year warranty — designed to match panel lifespan.
Factor in one inverter replacement at year 12–15 when calculating lifetime system economics.
What Happens After 25 Years?
Panels do not die at year 25 — they simply produce slightly less. A panel at 80% capacity is still generating free electricity. Options at year 25: continue using the system, add newer panels alongside old ones, or sell old panels to the second-hand agricultural market. MNRE has announced EPR (Extended Producer Responsibility) guidelines requiring manufacturers to set up panel recycling infrastructure.
Do hailstorms damage solar panels?
Tier 1 panels are tested to IEC 61215 standards — 25mm hailstones at 23 m/s — and pass without damage. Unusually large hailstorms can crack panels, but this is covered under home insurance. Always check your policy covers rooftop solar.
How do I know if my panel is underperforming?
Compare your inverter's daily generation to expected output for your system size and location. A consistent 10–15% underperformance after cleaning is worth investigating — could be a shading issue, faulty panel, or loose connection. Most inverter apps (Growatt, Solis, Goodwe) show daily generation data clearly.