February 19, 2026 / Solar Panel Understanding Solar Panel Warranty, Degradation & Long-Term Output
As rooftop solar adoption accelerates across India, more homeowners and businesses are evaluating not just the price of solar panels, but also their long-term performance and reliability.
While solar panels are marketed with 25-year warranties, many buyers do not fully understand:
A. What does the warranty actually cover?
B. How do solar panels degrade over time?
C. What happens to solar panel output after 10 or 20 years?
D. Does degradation affect ROI?
For Indian consumers investing in rooftop solar systems, understanding solar panel warranty in India is essential for making a future-ready decision.
What is a Solar Panel Warranty?
A solar panel warranty is the manufacturer’s assurance regarding: Product quality and Performance over time.
There are typically two types of warranties:
1. Product Warranty (Physical Warranty)
This covers:
A. Manufacturing defects
B. Material failures
C. Workmanship issues
Most manufacturers offer a 10- to 15-year product warranty, ensuring protection against early panel failure.
2. Performance Warranty (Power Output Warranty)
This guarantees:
A. Minimum power output over time
B. Performance stability across 25 years
Most panels guarantee:
a. Around 90% output after 10–12 years
b. Around 80–85% output after 25 years
This is known as the solar panel performance warranty.
What is Solar Panel Degradation?
All solar panels gradually lose efficiency over time. This process is called the solar panel degradation rate.
Degradation occurs due to:
1. UV exposure
2. Thermal cycling
3. Environmental stress
4. Micro-cracks
5. Moisture exposure
A typical annual degradation rate for high-quality solar panels is: 0.4% to 0.7% per year
A lower degradation rate means better long-term output.
How does Solar Panel Output change over 25 Years?
Let’s consider a simple example. If you install a 5kWrooftop solar system:
A. Year 1 output = 100%
B. After 10 years (0.5% annual degradation) = ~95%
C. After 25 years = ~87–88%
This means your solar panel output over 25 years remains largely stable if high-quality panels are used.
Panels with higher degradation rates may drop below 80% before 20 years, affecting long-term savings.
Solar Panel Lifespan in India: What to Expect
In Indian conditions, panels are exposed to:
1. High heat (45°C+)
2. Dust and pollution
3. Humidity in coastal areas
4. Heavy rainfall
High-quality panels designed for the Indian climate typically offer:
1. 25+ years lifespan
2. Strong encapsulation
3. Anti-PID protection
4. Robust frame construction
When evaluating solar panel reliability in India, climate compatibility is crucial.
Linear Warranty vs Step Warranty
Modern solar panels usually offer a linear performance warranty instead of a step warranty.
Step Warranty
Performance drops sharply after a fixed period.
Linear Warranty
Performance decreases gradually year by year at a defined degradation rate.
For example:
A. Maximum 2% drop in the first year
B. 0.45% annual degradation thereafter
A linear warranty provides more predictable long-term output.
Why Degradation Matters for Solar ROI in India?
Many buyers focus only on:
1. Initial system cost
2. Subsidy
3. Payback period
However, degradation affects:
1. Total lifetime energy generation
2. Long-term savings
3. Return on investment
A panel with 0.5% annual degradation will generate significantly more electricity over 25 years compared to one degrading at 0.8%. This directly impacts your solar ROI in India.
How to evaluate Solar Panel Warranty before Buying
Before selecting a rooftop solar system, check:
1. Product warranty duration
2. Performance warranty period (usually 25 years)
3. Guaranteed power output percentage
4. Annual degradation rate
5. Brand credibility
6. Service support network
Choosing the best solar panels with a long warranty in India ensures financial stability over the long term.
Common Misconceptions about Solar Panel Warranty
“A 25-year warranty means free replacement anytime.”
Not necessarily. Warranty terms apply to defined performance thresholds and manufacturing defects.
“Panels stop working after 25 years.”
No. Panels may continue generating electricity beyond 25 years, but at reduced output.
“All panels degrade at the same rate.”
No. High-quality panels degrade more slowly, ensuring better long-term solar panel efficiency.
Eastman Solar Panels: Designed for Long-Term Reliability
Eastman focuses on delivering reliable solar solutions aligned with Indian operating conditions. Eastman solar panels are designed with:
1. Advanced cell technology
2. Solar Panels ranging from 50W to 590W
3. In house manufacturing facility of 800 MW
4. Low degradation rate
5. Up to 27-year performance warranty
6. ALMM-approved models
7. Deliver dependable performance under harsh climates
8. Proudly made in India, designed for Indian climatic conditions
9. Backed by nationwide service and support
10. Smart monitoring via Eastman One App
By emphasizing durability and long-term output stability, Eastman supports customers seeking predictable solar performance and reliable investment returns.
Conclusion
Understanding solar panel warranty in India is essential before investing in a rooftop solar system.
Key takeaways:
1. Product warranty protects against manufacturing defects.
2. Performance warranty guarantees long-term output.
3. Degradation rate determines how much power your panels will produce after 10–25 years.
4. Lower degradation equals higher long-term ROI.
By choosing solar panels with transparent warranty terms, low degradation rates, and strong service support, homeowners and businesses can ensure reliable solar generation for decades.
As India’s solar market matures, long-term performance and warranty credibility will continue to define trusted brands in the industry.
Contact Eastman for more information.
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FAQ’s
Q1. What is the typical solar panel warranty in India?
Most solar panels offer a 10–15-year product warranty and a 25-year performance warranty.
Q2. What is the solar panel degradation rate?
It is the percentage of efficiency loss a solar panel experiences each year. High-quality panels typically degrade at 0.4%–0.7% annually.
Q3. How much output will solar panels produce after 25 years?
Most panels guarantee 80–85% of their original output under a linear performance warranty after 25 years.
Q4. What is the difference between a product warranty and a performance warranty?
The product warranty covers manufacturing defects, while the performance warranty guarantees minimum power output over time.
Q5. Do solar panels stop working after 25 years?
No. Panels continue generating electricity beyond 25 years, but at slightly reduced efficiency.
Q6. Does lower degradation improve solar ROI?
Yes. Lower degradation ensures higher electricity generation over time, improving overall return on investment.
Q7. Are Eastman solar panels designed for Indian conditions?
Yes. Eastman solar panels are developed with a focus on long-term performance and reliability under Indian climatic conditions.
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