Silfab SIL-500-NX 500W vs Waaree WS-440
The Silfab SIL-500-NX 500W wins this comparison by a decisive margin. It delivers more power (500W vs 440W). For most residential installations, the Silfab SIL-500-NX 500W is the stronger choice.
Key Differences
- • Silfab SIL-500-NX 500W is rated at 500W while Waaree WS-440 is rated at 440W, a 60W difference.
- • Both achieve identical 21.8% module efficiency.
- • Silfab SIL-500-NX 500W comes with a 25-year product warranty vs 12 years for the other.
- • Silfab SIL-500-NX 500W has a superior temperature coefficient of -0.29%/°C vs -0.3%/°C, retaining more power in hot climates.
Specifications Breakdown
Module Efficiency
Both the Silfab SIL-500-NX 500W and Waaree WS-440 share identical 21.8% module efficiency, producing comparable power per unit area. The Silfab SIL-500-NX 500W generates 210.6 W/m² while the Waaree WS-440 generates 225.3 W/m² based on their respective panel dimensions. With matched efficiency, neither panel holds a density advantage for space-constrained rooftop installations, so other factors like warranty coverage and temperature performance become the deciding metrics.
Power Output
The Silfab SIL-500-NX 500W delivers 500W per panel versus 440W for the Waaree WS-440, a 60W difference per module. To build an 8 kW residential system, you would need 16 Silfab SIL-500-NX 500W panels or 19 Waaree WS-440 panels. Choosing the higher-wattage option saves 3 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 Silfab SIL-500-NX 500W has a temperature coefficient of -0.29%/°C versus -0.3%/°C for the Waaree WS-440. On a hot summer day when cell temperature reaches 65°C (40°C above the 25°C STC baseline), the Silfab SIL-500-NX 500W retains 94.2% of its rated power while the other retains 94.0%. 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 Silfab SIL-500-NX 500W is backed by a 25-year product warranty and 30-year performance guarantee, while the Waaree WS-440 offers 12-year product and 25-year performance coverage. The Silfab SIL-500-NX 500W provides 13 additional years of defect protection, covering manufacturing issues, material failures, and premature performance loss. Based on their published degradation rates (1% first year then 0.4%/year for Silfab SIL-500-NX 500W; 1% first year then 0.4%/year for Waaree WS-440), after 25 years the Silfab SIL-500-NX 500W should retain approximately 89.4% of original output versus 89.4% for the Waaree WS-440. The end-of-life output levels are closely matched.
Physical Dimensions & Weight
The Silfab SIL-500-NX 500W measures 2094×1134×30mm and weighs 25.5 kg, while the Waaree WS-440 measures 1722×1134×30mm at 21.5 kg. 2.37 m² of panel area for the Silfab SIL-500-NX 500W versus 1.95 m² for the Waaree WS-440. The Waaree WS-440 is 4.0 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 80 kg. The more compact Waaree WS-440 may be easier to fit on irregularly shaped or space-limited rooftops.
Specification Comparison
| Specification | Silfab SIL-500-NX 500W | Waaree WS-440 |
|---|---|---|
| Power | 500W | 440W |
| Efficiency | 21.8% | 21.8% |
| Power Density | 19.6 W/sq ft | 20.9 W/sq ft |
| Cell Type | TOPCon N-type | TOPCon N-type |
| Bifacial | No | No |
| Weight | 25.5 kg | 21.5 kg |
| Temp Coefficient | -0.29%/°C | -0.3%/°C |
| Snow Load | 5400 Pa | 5400 Pa |
| Wind Load | 2400 Pa | 2400 Pa |
| Product Warranty | 25 years | 12 years |
| Performance Warranty | 30 years | 25 years |
| Degradation (Year 1) | 1% | 1% |
| Annual Degradation | 0.4% | 0.4% |
| Country | United States | India |
5-Dimension Head-to-Head Analysis
1. Efficiency & Power Density
Winner: TieBoth panels achieve 21.8% module efficiency, producing identical power per square meter. Neither has an advantage in space-constrained installations.
2. Hot Climate Performance
Winner: Silfab SIL-500-NX 500WThe Silfab SIL-500-NX 500W has a better temperature coefficient of -0.29%/°C versus -0.3%/°C. On a 45°C summer day (20°C above STC), the winner retains 94.2% of rated power versus 94.0%. The difference is modest but accumulates over 25 years of summer production.
3. Durability & Warranty
Winner: Silfab SIL-500-NX 500WSilfab SIL-500-NX 500W leads with a 25-year product warranty versus 12 years. After 25 years, expect 89.4% vs 89.4% of original output for Silfab SIL-500-NX 500W and Waaree WS-440 respectively.
4. Power Output
Winner: Silfab SIL-500-NX 500WThe Silfab SIL-500-NX 500W delivers 500W versus 440W per panel — 60W more. For an 8 kW system, you need 16 panels with the higher-wattage option versus 19 panels, saving 3 panels and the associated racking and labor costs.
5. Cell Technology
Winner: TieBoth panels use TOPCon N-type cell technology. No technology advantage for either product.
Silfab SIL-500-NX 500W
Silfab SIL-500-NX is a US-manufactured N-type TOPCon panel delivering 500W with domestic production benefits and a 25-year warranty.
Pros
- + Made in USA
- + 25-year product warranty
- + N-type TOPCon technology
- + Strong domestic support
Cons
- - Higher cost than imports
- - Moderate efficiency
- - Limited brand awareness
Waaree WS-440
The Waaree WS-440 is a 440W residential-format TOPCon N-type panel in the standard 108-cell configuration, manufactured at Waaree's state-of-the-art facilities in Gujarat, India. At 21.8% efficiency, it competes directly with Chinese TOPCon panels while offering Indian supply chain diversification. The standard 1722 x 1134mm form factor ensures compatibility with all major racking systems. Waaree's rapidly expanding US distribution makes this one of the most accessible Indian-made panels in the North American market.
Pros
- + Indian-manufactured — non-Chinese supply chain alternative
- + 21.8% efficiency competitive with Chinese TOPCon leaders
- + Standard 108-cell residential format — universal racking compatibility
- + -0.30%/°C temp coefficient for hot climate performance
- + Highly competitive pricing — among the lowest-cost TOPCon panels
- + Waaree's expanding US distribution improves availability
Cons
- - 12-year product warranty shorter than 25-year leaders
- - Indian manufacturing quality perception still developing vs established brands
- - US installer familiarity and support network still growing
- - No bifacial option in this residential format
Choose Silfab SIL-500-NX 500W If...
- ✓ You want fewer panels to reach your target system size, reducing racking and labor costs
- ✓ Long-term warranty protection is a top priority and you plan to stay in your home for 25+ years
- ✓ You live in a hot climate (Arizona, Texas, Florida) where heat performance matters
- ✓ You prefer newer cell technology with a longer performance improvement runway
- ✓ Homeowners prioritizing US-made solar panels with strong domestic warranty.
Choose Waaree WS-440 If...
- ✓ You prefer newer cell technology with a longer performance improvement runway
- ✓ Cost-conscious residential installers seeking high-efficiency TOPCon panels from a non-Chinese manufacturer at a competitive price point.
Our Recommendation
The Silfab SIL-500-NX 500W is the decisive winner in this solar panel comparison, outperforming the Waaree WS-440 in 3 of 5 dimensions. Unless you have a specific requirement that the Waaree WS-440 uniquely addresses, the Silfab SIL-500-NX 500W is the stronger choice for virtually every installation scenario.
Frequently Asked Questions
Which is better, Silfab SIL-500-NX 500W or Waaree WS-440?
The Silfab SIL-500-NX 500W wins this comparison by a decisive margin. It delivers more power (500W vs 440W). For most residential installations, the Silfab SIL-500-NX 500W is the stronger choice.
Which panel is more efficient, Silfab SIL-500-NX 500W or Waaree WS-440?
The both panels share 21.8% module efficiency. Higher efficiency means more watts per square foot of roof space, which is critical for space-constrained installations. The difference of 0.0 percentage points translates to approximately 60W per panel under standard test conditions.
Which has a better warranty, Silfab SIL-500-NX 500W or Waaree WS-440?
The Silfab SIL-500-NX 500W comes with a 25-year product warranty and 30-year performance guarantee. The Waaree WS-440 offers 12-year product and 25-year performance warranties. Silfab SIL-500-NX 500W provides 13 additional years of product coverage.
Which panel performs better in hot weather?
The Silfab SIL-500-NX 500W has a temperature coefficient of -0.29%/°C and the Waaree WS-440 is -0.3%/°C. Silfab SIL-500-NX 500W retains more power in heat — important in states like Arizona, Texas, and Florida. A lower (less negative) temperature coefficient is better.
How many Silfab SIL-500-NX 500W vs Waaree WS-440 panels do I need for an 8 kW system?
For an 8 kW system: you need 16 Silfab SIL-500-NX 500W panels (500W each) or 19 Waaree WS-440 panels (440W each). The Silfab SIL-500-NX 500W requires fewer panels, saving on racking hardware and installation labor.
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Last updated: February 2026