JA Solar JAM54S31 415W vs Silfab SIL-370-BK 370W
The Silfab SIL-370-BK 370W wins this comparison by a decisive margin. It offers better long-term durability with 25-year warranty. For most residential installations, the Silfab SIL-370-BK 370W is the stronger choice.
Key Differences
- • JA Solar JAM54S31 415W is rated at 415W while Silfab SIL-370-BK 370W is rated at 370W, a 45W difference.
- • JA Solar JAM54S31 415W achieves 21.5% efficiency vs 20.4% for the other, a 1.1 percentage point gap.
- • Silfab SIL-370-BK 370W comes with a 25-year product warranty vs 12 years for the other.
- • JA Solar JAM54S31 415W has a superior temperature coefficient of -0.34%/°C vs -0.35%/°C, retaining more power in hot climates.
Specifications Breakdown
Module Efficiency
The JA Solar JAM54S31 415W achieves 21.5% module efficiency compared to Silfab SIL-370-BK 370W's 20.4%, meaning JA Solar JAM54S31 415W converts 1.1 percentage points more sunlight into electricity per square meter. In practical terms, the JA Solar JAM54S31 415W produces 212.5 watts per square meter of panel area while the Silfab SIL-370-BK 370W produces 189.5 W/m². For rooftop installations where space is limited, this efficiency gap determines how many kilowatts you can fit on your available roof area. Over a 25-year system life, even a small efficiency advantage compounds into meaningful additional energy production.
Power Output
The JA Solar JAM54S31 415W delivers 415W per panel versus 370W for the Silfab SIL-370-BK 370W, a 45W difference per module. To build an 8 kW residential system, you would need 20 JA Solar JAM54S31 415W panels or 22 Silfab SIL-370-BK 370W panels. Choosing the higher-wattage option saves 2 panels, reducing total racking hardware, wiring, and installation labor costs. Higher wattage per panel is particularly valuable for commercial-scale installations where panel count directly impacts balance-of-system costs.
Temperature Coefficient
The JA Solar JAM54S31 415W has a temperature coefficient of -0.34%/°C versus -0.35%/°C for the Silfab SIL-370-BK 370W. On a hot summer day when cell temperature reaches 65°C (40°C above the 25°C STC baseline), the JA Solar JAM54S31 415W retains 93.2% of its rated power while the other retains 93.0%. While the numerical gap is modest, it still accumulates over decades of summer production, especially in southern latitudes with prolonged peak heat hours.
Warranty Coverage
The JA Solar JAM54S31 415W is backed by a 12-year product warranty and 25-year performance guarantee, while the Silfab SIL-370-BK 370W offers 25-year product and 25-year performance coverage. The Silfab SIL-370-BK 370W provides 13 additional years of defect protection, covering manufacturing issues, material failures, and premature performance loss. Based on their published degradation rates (1.5% first year then 0.5%/year for JA Solar JAM54S31 415W; 1% first year then 0.4%/year for Silfab SIL-370-BK 370W), after 25 years the JA Solar JAM54S31 415W should retain approximately 86.5% of original output versus 89.4% for the Silfab SIL-370-BK 370W. This 2.9 percentage point gap in end-of-life output meaningfully impacts lifetime energy economics.
Physical Dimensions & Weight
The JA Solar JAM54S31 415W measures 1722×1134×30mm and weighs 21.5 kg, while the Silfab SIL-370-BK 370W measures 1722×1134×30mm at 19.5 kg. 1.95 m² of panel area for the JA Solar JAM54S31 415W versus 1.95 m² for the Silfab SIL-370-BK 370W. The Silfab SIL-370-BK 370W is 2.0 kg lighter per panel, which reduces structural load requirements on the roof and makes handling easier during installation. For a 20-panel system, that is a total weight difference of 40 kg. Similar footprints mean both panels fit comparably on standard residential rooftop configurations.
Specification Comparison
| Specification | JA Solar JAM54S31 415W | Silfab SIL-370-BK 370W |
|---|---|---|
| Power | 415W | 370W |
| Efficiency | 21.5% | 20.4% |
| Power Density | 19.7 W/sq ft | 17.6 W/sq ft |
| Cell Type | PERC Mono | PERC Mono |
| Bifacial | No | No |
| Weight | 21.5 kg | 19.5 kg |
| Temp Coefficient | -0.34%/°C | -0.35%/°C |
| Snow Load | 5400 Pa | 2400 Pa |
| Wind Load | 2400 Pa | 2400 Pa |
| Product Warranty | 12 years | 25 years |
| Performance Warranty | 25 years | 25 years |
| Degradation (Year 1) | 1.5% | 1% |
| Annual Degradation | 0.5% | 0.4% |
| Country | China | United States |
5-Dimension Head-to-Head Analysis
1. Efficiency & Power Density
Winner: JA Solar JAM54S31 415WThe JA Solar JAM54S31 415W achieves 21.5% efficiency versus 20.4% — a 1.1 percentage point advantage. On a typical 30-panel residential roof, this translates to approximately 1.4 kW more total system capacity, or 7 kWh more annual production in an average US location.
2. Hot Climate Performance
Winner: JA Solar JAM54S31 415WThe JA Solar JAM54S31 415W has a better temperature coefficient of -0.34%/°C versus -0.35%/°C. On a 45°C summer day (20°C above STC), the winner retains 93.2% of rated power versus 93.0%. The difference is modest but accumulates over 25 years of summer production.
3. Durability & Warranty
Winner: Silfab SIL-370-BK 370WSilfab SIL-370-BK 370W leads with a 25-year product warranty versus 12 years. Silfab SIL-370-BK 370W degrades more slowly at 0.4% per year versus 0.5%. After 25 years, expect 86.5% vs 89.4% of original output for JA Solar JAM54S31 415W and Silfab SIL-370-BK 370W respectively.
4. Power Output
Winner: JA Solar JAM54S31 415WThe JA Solar JAM54S31 415W delivers 415W versus 370W per panel — 45W more. For an 8 kW system, you need 20 panels with the higher-wattage option versus 22 panels, saving 2 panels and the associated racking and labor costs.
5. Cell Technology
Winner: TieBoth panels use PERC Mono cell technology. No technology advantage for either product.
JA Solar JAM54S31 415W
The JAM54S31 is a compact residential PERC panel delivering 415W with a solid balance of performance and affordability.
Pros
- + Compact residential form factor
- + Good price-performance ratio
- + Widely available
- + Proven reliability
Cons
- - Lower efficiency vs N-type
- - Higher degradation rate
- - Standard warranty
Silfab SIL-370-BK 370W
The SIL-370-BK is Silfab's entry-level US-made all-black panel delivering 370W for budget-conscious domestic installations.
Pros
- + Made in USA
- + All-black design
- + 25-year warranty
- + ARRA compliant
Cons
- - Lower wattage
- - Basic PERC technology
- - Less competitive efficiency
Choose JA Solar JAM54S31 415W If...
- ✓ Your roof space is limited and you need maximum power per panel
- ✓ You want fewer panels to reach your target system size, reducing racking and labor costs
- ✓ You live in a hot climate (Arizona, Texas, Florida) where heat performance matters
- ✓ Budget residential installations seeking reliable PERC performance.
Choose Silfab SIL-370-BK 370W If...
- ✓ Long-term warranty protection is a top priority and you plan to stay in your home for 25+ years
- ✓ You want maximum output retention over the system's 25-30 year lifespan
- ✓ Government or institutional projects requiring ARRA/Buy America compliance.
Our Recommendation
The Silfab SIL-370-BK 370W is the decisive winner in this solar panel comparison, outperforming the JA Solar JAM54S31 415W in 1 of 5 dimensions. Unless you have a specific requirement that the JA Solar JAM54S31 415W uniquely addresses, the Silfab SIL-370-BK 370W is the stronger choice for virtually every installation scenario.
Frequently Asked Questions
Which is better, JA Solar JAM54S31 415W or Silfab SIL-370-BK 370W?
The Silfab SIL-370-BK 370W wins this comparison by a decisive margin. It offers better long-term durability with 25-year warranty. For most residential installations, the Silfab SIL-370-BK 370W is the stronger choice.
Which panel is more efficient, JA Solar JAM54S31 415W or Silfab SIL-370-BK 370W?
The JA Solar JAM54S31 415W at 21.5% module efficiency. Higher efficiency means more watts per square foot of roof space, which is critical for space-constrained installations. The difference of 1.1 percentage points translates to approximately 45W per panel under standard test conditions.
Which has a better warranty, JA Solar JAM54S31 415W or Silfab SIL-370-BK 370W?
The JA Solar JAM54S31 415W comes with a 12-year product warranty and 25-year performance guarantee. The Silfab SIL-370-BK 370W offers 25-year product and 25-year performance warranties. Silfab SIL-370-BK 370W provides 13 additional years of product coverage.
Which panel performs better in hot weather?
The JA Solar JAM54S31 415W has a temperature coefficient of -0.34%/°C and the Silfab SIL-370-BK 370W is -0.35%/°C. JA Solar JAM54S31 415W retains more power in heat — important in states like Arizona, Texas, and Florida. A lower (less negative) temperature coefficient is better.
How many JA Solar JAM54S31 415W vs Silfab SIL-370-BK 370W panels do I need for an 8 kW system?
For an 8 kW system: you need 20 JA Solar JAM54S31 415W panels (415W each) or 22 Silfab SIL-370-BK 370W panels (370W each). The JA Solar JAM54S31 415W requires fewer panels, saving on racking hardware and installation labor.
Related Resources
Last updated: February 2026