Solaria PowerXT 400R Pure Black vs Waaree WS-440
The Solaria PowerXT 400R Pure Black wins this comparison by a clear margin. It offers better long-term durability with 25-year warranty. For most residential installations, the Solaria PowerXT 400R Pure Black is the stronger choice.
Key Differences
- • Solaria PowerXT 400R Pure Black is rated at 400W while Waaree WS-440 is rated at 440W, a 40W difference.
- • Waaree WS-440 achieves 21.8% efficiency vs 20.5% for the other, a 1.3 percentage point gap.
- • Solaria PowerXT 400R Pure Black comes with a 25-year product warranty vs 12 years for the other.
- • Waaree WS-440 has a superior temperature coefficient of -0.3%/°C vs -0.34%/°C, retaining more power in hot climates.
- • Solaria PowerXT 400R Pure Black uses Shingled Mono PERC cells while Waaree WS-440 uses TOPCon N-type cells, representing different technology generations.
Specifications Breakdown
Module Efficiency
The Waaree WS-440 achieves 21.8% module efficiency compared to Solaria PowerXT 400R Pure Black's 20.5%, meaning Waaree WS-440 converts 1.3 percentage points more sunlight into electricity per square meter. In practical terms, the Solaria PowerXT 400R Pure Black produces 205.3 watts per square meter of panel area while the Waaree WS-440 produces 225.3 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 Waaree WS-440 delivers 440W per panel versus 400W for the Solaria PowerXT 400R Pure Black, a 40W difference per module. To build an 8 kW residential system, you would need 20 Solaria PowerXT 400R Pure Black panels or 19 Waaree WS-440 panels. Choosing the higher-wattage option saves 1 panel, 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 Waaree WS-440 has a temperature coefficient of -0.3%/°C versus -0.34%/°C for the Solaria PowerXT 400R Pure Black. On a hot summer day when cell temperature reaches 65°C (40°C above the 25°C STC baseline), the Waaree WS-440 retains 94.0% of its rated power while the other retains 93.2%. 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 Solaria PowerXT 400R Pure Black is backed by a 25-year product warranty and 25-year performance guarantee, while the Waaree WS-440 offers 12-year product and 25-year performance coverage. The Solaria PowerXT 400R Pure Black 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 0.4%/year for Solaria PowerXT 400R Pure Black; 1% first year then 0.4%/year for Waaree WS-440), after 25 years the Solaria PowerXT 400R Pure Black should retain approximately 88.9% of original output versus 89.4% for the Waaree WS-440. The end-of-life output levels are closely matched.
Physical Dimensions & Weight
The Solaria PowerXT 400R Pure Black measures 1812×1075×40mm and weighs 21.5 kg, while the Waaree WS-440 measures 1722×1134×30mm at 21.5 kg. 1.95 m² of panel area for the Solaria PowerXT 400R Pure Black versus 1.95 m² for the Waaree WS-440. Their weights are closely matched, so neither panel imposes a significantly different structural load on the mounting system. Similar footprints mean both panels fit comparably on standard residential rooftop configurations.
Specification Comparison
| Specification | Solaria PowerXT 400R Pure Black | Waaree WS-440 |
|---|---|---|
| Power | 400W | 440W |
| Efficiency | 20.5% | 21.8% |
| Power Density | 19.1 W/sq ft | 20.9 W/sq ft |
| Cell Type | Shingled Mono PERC | TOPCon N-type |
| Bifacial | No | No |
| Weight | 21.5 kg | 21.5 kg |
| Temp Coefficient | -0.34%/°C | -0.3%/°C |
| Snow Load | 5400 Pa | 5400 Pa |
| Wind Load | 2400 Pa | 2400 Pa |
| Product Warranty | 25 years | 12 years |
| Performance Warranty | 25 years | 25 years |
| Degradation (Year 1) | 1.5% | 1% |
| Annual Degradation | 0.4% | 0.4% |
| Country | USA | India |
5-Dimension Head-to-Head Analysis
1. Efficiency & Power Density
Winner: Waaree WS-440The Waaree WS-440 achieves 21.8% efficiency versus 20.5% — a 1.3 percentage point advantage. On a typical 30-panel residential roof, this translates to approximately 1.2 kW more total system capacity, or 6 kWh more annual production in an average US location.
2. Hot Climate Performance
Winner: Waaree WS-440The Waaree WS-440 has a better temperature coefficient of -0.3%/°C versus -0.34%/°C. On a 45°C summer day (20°C above STC), the winner retains 94.0% of rated power versus 93.2%. The difference is modest but accumulates over 25 years of summer production.
3. Durability & Warranty
Winner: Solaria PowerXT 400R Pure BlackSolaria PowerXT 400R Pure Black leads with a 25-year product warranty versus 12 years. After 25 years, expect 88.9% vs 89.4% of original output for Solaria PowerXT 400R Pure Black and Waaree WS-440 respectively.
4. Power Output
Winner: Waaree WS-440The Waaree WS-440 delivers 440W versus 400W per panel — 40W more. For an 8 kW system, you need 19 panels with the higher-wattage option versus 20 panels, saving 1 panels and the associated racking and labor costs.
5. Cell Technology
Winner: Waaree WS-440The Solaria PowerXT 400R Pure Black uses Shingled Mono PERC: PERC (Passivated Emitter Rear Cell) is the current mainstream technology, offering good efficiency at the lowest manufacturing cost. The Waaree WS-440 uses TOPCon N-type: TOPCon (Tunnel Oxide Passivated Contact) adds a thin tunnel oxide layer to reduce recombination losses, achieving higher efficiency than PERC while being manufacturable on existing production lines. TOPCon N-type represents a newer generation technology with a longer performance runway as manufacturing matures.
Solaria PowerXT 400R Pure Black
The Solaria PowerXT 400R Pure Black is the compact residential variant of Solaria's shingled-cell panel line, delivering 400W in a smaller form factor optimized for constrained rooftops. The shingled cell architecture produces a completely uniform black surface — no visible busbars, cell gaps, or gridlines — making it one of the most aesthetically appealing panels on the market. Manufactured in Fremont, California, it qualifies for domestic content bonus ITC credits. The 400W output in a compact footprint makes it suitable for smaller residential roofs where every square foot counts.
Pros
- + Industry-leading all-black aesthetics — completely uniform surface
- + Compact size fits constrained residential rooftops
- + US-manufactured — domestic content ITC bonus eligible
- + Shingled cells improve shade tolerance and eliminate hot spots
- + 25-year dual warranty (product + performance)
- + No busbar visibility for premium curb appeal
Cons
- - 400W output lower than larger-format competitors
- - Higher per-watt cost for the aesthetic and US-made premium
- - Smaller installer network than mainstream brands
- - 20.5% efficiency is good but not class-leading
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 Solaria PowerXT 400R Pure Black If...
- ✓ Long-term warranty protection is a top priority and you plan to stay in your home for 25+ years
- ✓ Homeowners with visible roof installations who demand the best-looking all-black panel with American manufacturing and domestic content tax benefits.
Choose Waaree WS-440 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
- ✓ 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
We recommend the Solaria PowerXT 400R Pure Black for most buyers in this comparison. It wins 1 of 5 key dimensions and offers a clear advantage in the metrics that matter most for a solar panel purchase. The Waaree WS-440 remains a good product, but the Solaria PowerXT 400R Pure Black delivers better overall value for the majority of installations.
Frequently Asked Questions
Which is better, Solaria PowerXT 400R Pure Black or Waaree WS-440?
The Solaria PowerXT 400R Pure Black wins this comparison by a clear margin. It offers better long-term durability with 25-year warranty. For most residential installations, the Solaria PowerXT 400R Pure Black is the stronger choice.
Which panel is more efficient, Solaria PowerXT 400R Pure Black or Waaree WS-440?
The Waaree WS-440 at 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 1.3 percentage points translates to approximately 40W per panel under standard test conditions.
Which has a better warranty, Solaria PowerXT 400R Pure Black or Waaree WS-440?
The Solaria PowerXT 400R Pure Black comes with a 25-year product warranty and 25-year performance guarantee. The Waaree WS-440 offers 12-year product and 25-year performance warranties. Solaria PowerXT 400R Pure Black provides 13 additional years of product coverage.
Which panel performs better in hot weather?
The Solaria PowerXT 400R Pure Black has a temperature coefficient of -0.34%/°C and the Waaree WS-440 is -0.3%/°C. Waaree WS-440 retains more power in heat — important in states like Arizona, Texas, and Florida. A lower (less negative) temperature coefficient is better.
How many Solaria PowerXT 400R Pure Black vs Waaree WS-440 panels do I need for an 8 kW system?
For an 8 kW system: you need 20 Solaria PowerXT 400R Pure Black panels (400W each) or 19 Waaree WS-440 panels (440W each). The Waaree WS-440 requires fewer panels, saving on racking hardware and installation labor.
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Last updated: February 2026