The Big Picture: How Panel Tech Has Evolved by 2025
Polycrystalline panels—once common in earlier years—are now nearly obsolete. They had efficiencies capped around 18–21%, and today nearly all manufacturers focus on monocrystalline-based cell types for much higher performance
Today’s mainstream panel types—Mono‑PERC, TOPCon, and HJT—are all variations within monocrystalline silicon technology, offering sharply improved efficiencies and reliability.
Panel Types Compared
Polycrystalline
- Efficiency: ~18–21%
- Strengths: Lower cost, simpler manufacturing
- Weaknesses: Lower power density, now rarely produced
Mono‑PERC (Passivated Emitter Rear Cell)
Efficiency: ~20–23%
Strengths: Proven tech, widely available, affordable, good power output
Weaknesses: Modest degradation in hot conditions, limited performance in low light
TOPCon (Tunnel Oxide Passivated Contact)
Efficiency: ~24–28% in mass production by mid‑2025
Strengths: Excellent low-light and temperature tolerance, enhanced bifaciality (~85%), lower degradation (~1.5% first-year loss), scalable via existing PERC lines
Weaknesses: Slightly higher cost than PERC, though falling rapidly; requires upgrade lines
HJT (Heterojunction Technology)
Efficiency: Up to ~26–26.7%; bifacial output can exceed 30% in optimal installations Clean Energy Reviews+4Sunhub+4Sunhub+4
Strengths: Superior performance in high heat, ultra-low degradation, exceptional bifaciality (>90%), longer lifespan, low temperature coefficients
Weaknesses: Most expensive to manufacture, requires entirely new lines, sensitive to humidity, limited large-scale Indian production
How They Stack Up: Efficiency, Durability & Cost
| Panel Type | Efficiency | Degradation Rate | Bifacial Yield | Durability | Relative Cost | Best For |
|---|---|---|---|---|---|---|
| Polycrystalline | 18–21% | Moderate | None | Moderate | Lowest | Budget or older installations |
| Mono‑PERC | 20–23% | ~2% first year | ~70% | High | Low–mid | Standard residential or commercial |
| TOPCon | 24–28% | ~1.5% → ~89% clarity after 25 years | ~85% | Very High | Mid–high (dropping quickly) | High-efficiency and value balance |
| HJT | 26–27% (mono), >30% bifacial | ~1% → best retention | >90% | Exceptional (30+ year life) | Highest | Ultra-efficiency, heat, and long lifespan |
Choosing the Right Panel in 2025
For Most Homes and Businesses:
Mono‑PERC remains a reliable and cost-effective option, delivering solid performance at a low price point. But if you want more yield…
For Higher Performance and Future‑Proofing:
TOPCon strikes the best balance—higher efficiency, strong durability, good low-light behaviour, and improved bifacial yields—while leveraging scalable production methods at a reasonable price.
For Ultra-Premium Applications:
HJT reigns supreme if your focus is maximum lifetime yield, minimal temperature losses, and industry-leading durability. However, expect higher upfront cost and limited availability.
Key Takeaways for Buyers in 2025
Skip polycrystalline—modern installations almost always use monocrystalline variants.
Mono‑PERC is a safe, budget‑smart choice for solid performance today.
TOPCon is ideal if you want premium efficiency and scalability without breaking the bank.
HJT is the top-tier option—for users who prioritize the highest yield and longest lifetime and are willing to invest upfront.
Make sure the panel brand provides solid warranty coverage, framed construction, and service support.
FAQ’s
1: Are polycrystalline panels still available today?
Very few. Production has mostly shifted to monocrystalline types due to efficiency limitations of polycrystalline panels
2: How much better are TOPCon panels than mono‑PERC?
TOPCon panels offer about 1–3% higher efficiency, better resistance to temperature and low-light degradation, and stronger long-term performance/tariff yield
3: Is HJT worth the extra cost?
If you want the absolute best efficiency, lowest degradation, and optimal performance in hot or humid climates, yes—HJT panels justify the premium. But they cost more to manufacture and may not be widely available locally
4: Can I upgrade from PERC to TOPCon easily in India?
Yes—TOPCon production lines can often be built by retrofitting PERC lines, helping it scale faster and more cheaply across Indian manufacturing plants
5: Which is most reliable in hot climates?
Both TOPCon and HJT outperform PERC in high temperatures, but HJT has a slightly superior temperature coefficient and lower long-term degradation—though at a higher price