Canadian Solar CS6R 420W vs Solaria PowerXT 400R Pure Black
The Solaria PowerXT 400R Pure Black wins this comparison by a decisive 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
- • Canadian Solar CS6R 420W is rated at 420W while Solaria PowerXT 400R Pure Black is rated at 400W, a 20W difference.
- • Canadian Solar CS6R 420W achieves 21% efficiency vs 20.5% for the other, a 0.5 percentage point gap.
- • Solaria PowerXT 400R Pure Black comes with a 25-year product warranty vs 12 years for the other.
- • Canadian Solar CS6R 420W uses PERC Mono cells while Solaria PowerXT 400R Pure Black uses Shingled Mono PERC cells, representing different technology generations.
Specifications Breakdown
Module Efficiency
The Canadian Solar CS6R 420W achieves 21% module efficiency compared to Solaria PowerXT 400R Pure Black's 20.5%, meaning Canadian Solar CS6R 420W converts 0.5 percentage points more sunlight into electricity per square meter. In practical terms, the Canadian Solar CS6R 420W produces 215.1 watts per square meter of panel area while the Solaria PowerXT 400R Pure Black produces 205.3 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 Canadian Solar CS6R 420W delivers 420W per panel versus 400W for the Solaria PowerXT 400R Pure Black, a 20W difference per module. To build an 8 kW residential system, you would need 20 Canadian Solar CS6R 420W panels or 20 Solaria PowerXT 400R Pure Black panels. Despite the per-panel wattage difference, both require the same number of panels for this system size due to rounding. Higher wattage per panel is particularly valuable for commercial-scale installations where panel count directly impacts balance-of-system costs.
Temperature Coefficient
Both panels share an identical temperature coefficient of -0.34%/°C, meaning they lose power at the same rate as cell temperature rises above the 25°C standard test baseline. At 65°C cell temperature, both retain 93.2% of rated power. Neither panel has a thermal performance advantage, which makes this specification a non-factor in the comparison.
Warranty Coverage
The Canadian Solar CS6R 420W is backed by a 12-year product warranty and 25-year performance guarantee, while the Solaria PowerXT 400R Pure Black offers 25-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 0.5%/year for Canadian Solar CS6R 420W; 1.5% first year then 0.4%/year for Solaria PowerXT 400R Pure Black), after 25 years the Canadian Solar CS6R 420W should retain approximately 86.5% of original output versus 88.9% for the Solaria PowerXT 400R Pure Black. This 2.4 percentage point gap in end-of-life output meaningfully impacts lifetime energy economics.
Physical Dimensions & Weight
The Canadian Solar CS6R 420W measures 1722×1134×30mm and weighs 21 kg, while the Solaria PowerXT 400R Pure Black measures 1812×1075×40mm at 21.5 kg. 1.95 m² of panel area for the Canadian Solar CS6R 420W versus 1.95 m² for the Solaria PowerXT 400R Pure Black. 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 | Canadian Solar CS6R 420W | Solaria PowerXT 400R Pure Black |
|---|---|---|
| Power | 420W | 400W |
| Efficiency | 21% | 20.5% |
| Power Density | 20.0 W/sq ft | 19.1 W/sq ft |
| Cell Type | PERC Mono | Shingled Mono PERC |
| Bifacial | No | No |
| Weight | 21 kg | 21.5 kg |
| Temp Coefficient | -0.34%/°C | -0.34%/°C |
| Snow Load | 5400 Pa | 5400 Pa |
| Wind Load | 2400 Pa | 2400 Pa |
| Product Warranty | 12 years | 25 years |
| Performance Warranty | 25 years | 25 years |
| Degradation (Year 1) | 1.5% | 1.5% |
| Annual Degradation | 0.5% | 0.4% |
| Country | China | USA |
5-Dimension Head-to-Head Analysis
1. Efficiency & Power Density
Winner: Canadian Solar CS6R 420WThe Canadian Solar CS6R 420W achieves 21% efficiency versus 20.5% — a 0.5 percentage point advantage. On a typical 30-panel residential roof, this translates to approximately 0.6 kW more total system capacity, or 3 kWh more annual production in an average US location.
2. Hot Climate Performance
Winner: TieBoth panels share a temperature coefficient of -0.34%/°C — identical heat tolerance.
3. Durability & Warranty
Winner: Solaria PowerXT 400R Pure BlackSolaria PowerXT 400R Pure Black leads with a 25-year product warranty versus 12 years. Solaria PowerXT 400R Pure Black degrades more slowly at 0.4% per year versus 0.5%. After 25 years, expect 86.5% vs 88.9% of original output for Canadian Solar CS6R 420W and Solaria PowerXT 400R Pure Black respectively.
4. Power Output
Winner: Canadian Solar CS6R 420WThe Canadian Solar CS6R 420W delivers 420W versus 400W per panel — 20W more. For an 8 kW system, you need 20 panels with the higher-wattage option versus 20 panels, saving 0 panels and the associated racking and labor costs.
5. Cell Technology
Winner: TieThe Canadian Solar CS6R 420W uses PERC Mono: PERC (Passivated Emitter Rear Cell) is the current mainstream technology, offering good efficiency at the lowest manufacturing cost. The 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. Both are equivalent-generation technologies.
Canadian Solar CS6R 420W
The CS6R is Canadian Solar's residential PERC workhorse delivering 420W in a compact, roof-friendly form factor.
Pros
- + Compact residential size
- + Affordable pricing
- + Proven track record
- + Easy installation
Cons
- - Older PERC technology
- - Standard performance
- - Higher degradation
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
Choose Canadian Solar CS6R 420W 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
- ✓ Budget residential installations from a bankable Tier 1 brand.
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
- ✓ You want maximum output retention over the system's 25-30 year lifespan
- ✓ Homeowners with visible roof installations who demand the best-looking all-black panel with American manufacturing and domestic content tax benefits.
Our Recommendation
The Solaria PowerXT 400R Pure Black is the decisive winner in this solar panel comparison, outperforming the Canadian Solar CS6R 420W in 1 of 5 dimensions. Unless you have a specific requirement that the Canadian Solar CS6R 420W uniquely addresses, the Solaria PowerXT 400R Pure Black is the stronger choice for virtually every installation scenario.
Frequently Asked Questions
Which is better, Canadian Solar CS6R 420W or Solaria PowerXT 400R Pure Black?
The Solaria PowerXT 400R Pure Black wins this comparison by a decisive 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, Canadian Solar CS6R 420W or Solaria PowerXT 400R Pure Black?
The Canadian Solar CS6R 420W at 21% module efficiency. Higher efficiency means more watts per square foot of roof space, which is critical for space-constrained installations. The difference of 0.5 percentage points translates to approximately 20W per panel under standard test conditions.
Which has a better warranty, Canadian Solar CS6R 420W or Solaria PowerXT 400R Pure Black?
The Canadian Solar CS6R 420W comes with a 12-year product warranty and 25-year performance guarantee. The Solaria PowerXT 400R Pure Black offers 25-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 Canadian Solar CS6R 420W has a temperature coefficient of -0.34%/°C and the Solaria PowerXT 400R Pure Black is -0.34%/°C. Both handle heat equally. A lower (less negative) temperature coefficient is better.
How many Canadian Solar CS6R 420W vs Solaria PowerXT 400R Pure Black panels do I need for an 8 kW system?
For an 8 kW system: you need 20 Canadian Solar CS6R 420W panels (420W each) or 20 Solaria PowerXT 400R Pure Black panels (400W each). The Canadian Solar CS6R 420W requires fewer panels, saving on racking hardware and installation labor.
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Last updated: February 2026