Canadian Solar CS6R 420W Specifications & Review
The CS6R is Canadian Solar's residential PERC workhorse delivering 420W in a compact, roof-friendly form factor.
What Makes the Canadian Solar CS6R 420W Different
The Canadian Solar CS6R 420W is the quintessential budget-friendly residential solar panel from one of the world's most bankable Tier 1 manufacturers. While many competitors have shifted to newer TOPCon or HJT cell technologies, the CS6R uses proven PERC monocrystalline cells in a 108-cell half-cut configuration, prioritizing manufacturing maturity and cost efficiency over bleeding-edge performance. At 21.0% efficiency, it sits in the middle of the pack — but what sets it apart is the combination of its compact 1722×1134mm form factor (easily fitting standard residential roof sections), a strong 5400 Pa snow load rating, and Canadian Solar's extensive global distribution network that keeps prices among the lowest of any Tier 1 brand. With over 70 GW shipped worldwide, Canadian Solar's supply chain reliability is a genuine differentiator for installers who need consistent availability and proven bankability for project financing.
Key Specifications
| Brand | Canadian Solar |
| Model | Canadian Solar CS6R 420W |
| Power Output | 420W |
| Efficiency | 21% |
| Power Density | 20.0 W/sq ft |
| Cell Type | PERC Mono |
| Cell Count | 108 cells |
| Dimensions | 1722 x 1134 x 30 mm |
| Weight | 21 kg |
| Open Circuit Voltage (Voc) | 40.5V |
| Max Power Voltage (Vmp) | 33.8V |
| Short Circuit Current (Isc) | 13.42A |
| Max Power Current (Imp) | 12.43A |
| Temp Coefficient (Pmax) | -0.34%/°C |
| Product Warranty | 12 years |
| Performance Warranty | 25 years |
| First Year Degradation | 1.5% |
| Annual Degradation | 0.5% |
| Country of Manufacture | China |
| Certifications | IEC 61215, IEC 61730, UL 1703 |
| Snow Load | 5400 Pa (112.8 psf) — Heavy Snow Rated |
| Wind Load | 2400 Pa (50.1 psf) |
Pros & Cons
Pros
- ✓ Compact residential size
- ✓ Affordable pricing
- ✓ Proven track record
- ✓ Easy installation
Cons
- ✗ Older PERC technology
- ✗ Standard performance
- ✗ Higher degradation
Best For
Budget residential installations from a bankable Tier 1 brand.
Is the Canadian Solar CS6R 420W Worth It?
The Canadian Solar CS6R 420W delivers 420W of power at 21% module efficiency, which is near the current industry average of approximately 21%. While not the highest-efficiency option on the market, it may offer compelling value depending on price and your available roof space.
From a warranty perspective, the CS6R 420W comes with a standard 12-year product warranty and a 25-year performance guarantee. The industry standard for product warranties ranges from 12 to 25 years, so you may want to weigh this shorter warranty against the overall system cost. At the end of 25 years, the panel is guaranteed to still produce approximately 86.5% of its rated output, with first-year degradation of 1.5% and just 0.5% per year after that.
Pricing varies by region and installer, but the CS6R 420W's combination of 21% efficiency and 12-year warranty should be weighed against per-watt quotes from your installer. Request at least three quotes to ensure you are getting competitive pricing for this tier of panel.
For hot climates, the temperature coefficient of -0.34%/°C is good. This falls within the typical range, so you can expect reasonable performance in most climates, though premium panels with coefficients closer to -0.25%/°C will edge ahead in extreme heat. Overall, the Canadian Solar CS6R 420W can be a reasonable choice depending on your budget and performance requirements.
Real-World Performance
In real-world conditions, the CS6R 420W performs predictably but not exceptionally. Its -0.34%/°C temperature coefficient means it loses about 13.6-15.3% of rated output on hot summer days when cell temperatures reach 65-70°C — roughly 2-4% more loss than TOPCon panels in the same conditions. The 1.5% first-year degradation and 0.5% annual degradation are standard for PERC technology but notably higher than newer N-type panels that typically offer 1.0% and 0.4% respectively. After 25 years, expect the CS6R to produce approximately 86.5% of its rated 420W. The 108-cell design provides a favorable voltage-to-current ratio for most residential string inverters, and the 21 kg weight makes it manageable for two-person roof installations.
Who Should Buy the Canadian Solar CS6R 420W?
System Design Tips
String between 8-12 panels per MPPT input on most residential inverters to stay within the optimal voltage window. The 40.5V Voc means cold-climate installers should verify string Voc stays below inverter maximum at local record low temperatures. Pair with a SolarEdge or Enphase system if partial shading is present, as panel-level optimization compensates for the CS6R's lack of built-in shade tolerance features.
Price Estimate
The CS6R 420W typically prices between $0.28-$0.38 per watt at distributor level, making it one of the most affordable Tier 1 panels available. For a 20-panel (8.4 kW) residential system, panel cost runs approximately $2,350-$3,190 before installation. Canadian Solar frequently offers volume pricing that brings per-watt costs even lower for larger orders.
How the Canadian Solar CS6R 420W Compares
| Model | Wattage | Efficiency | W/sq ft | Warranty | Snow Load | Cell Type |
|---|---|---|---|---|---|---|
| Canadian Solar CS6R 420W (this panel) | 420W | 21% | 20.0 | 12 yrs | 5400 Pa | PERC Mono |
| Trina Solar Vertex S 420W | 420W | 21.3% | 19.5 | 15 yrs | 5400 Pa | PERC Mono |
| REC TwinPeak 5 420W | 420W | 21.4% | 20.0 | 20 yrs | 5400 Pa | PERC Mono |
| Q CELLS Q.TRON BLK M-G11+ 420W | 420W | 21.6% | 20.0 | 25 yrs | 5400 Pa | TOPCon N-type |
Compare This Panel
Installation & Compatibility
System Voltage & String Sizing
- Open Circuit Voltage (Voc)
- 40.5V
- Max Power Voltage (Vmp)
- 33.8V
- Short Circuit Current (Isc)
- 13.42A
- Max Power Current (Imp)
- 12.43A
- Max Panels per String (600V)
- 14 panels
Based on NEC 600V residential limit. Actual string sizing should account for cold-temperature Voc rise. Consult your installer or use a string sizing tool for your specific location.
Mounting Requirements
- Dimensions
- 1722 x 1134 x 30 mm
- Weight
- 21 kg (46.3 lbs)
- Area per Panel
- 21.0 sq ft
- Weight per sq ft
- 2.2 lbs/sq ft
Recommended Inverter Types
- - Microinverters: Ideal for shaded roofs or complex layouts. Match to panels rated 420W+.
- - String Inverters: Cost-effective for unshaded arrays. Ensure MPPT range covers 33.8V.
- - Hybrid Inverters: Best if adding battery storage. Check DC input specs match panel Voc of 40.5V.
Frequently Asked Questions
How does the CS6R 420W compare to Canadian Solar's newer TOPCon panels?
The CS6R uses older PERC technology with 21.0% efficiency versus 22-23% for Canadian Solar's TOPCon HiKu7 series. The CS6R has higher degradation (1.5% first year vs 1.0%) and a worse temperature coefficient (-0.34% vs -0.29%), but costs significantly less per watt. For budget-focused installations where roof space is not constrained, the CS6R delivers better value per dollar.
Is the CS6R 420W suitable for areas with heavy snow?
Yes. With a 5400 Pa front-side snow load rating, the CS6R can handle substantial snow accumulation — equivalent to approximately 1.5-2 feet of packed snow. This exceeds the requirements for most North American residential installations, including regions in the northern US and Canada.
What inverters pair best with the CS6R 420W?
The CS6R works well with virtually any residential inverter. For cost-optimized systems, pair with string inverters like the SMA Sunny Boy or Fronius Primo. For shaded roofs, Enphase IQ8+ or IQ8M microinverters or SolarEdge optimizers are recommended. The 33.8V Vmp and 12.43A Imp are compatible with all major residential inverter brands.
What is the efficiency of the Canadian Solar CS6R 420W?
The Canadian Solar CS6R 420W achieves 21% module efficiency using PERC Mono cell technology. This is around the industry average for residential solar panels in 2026.
What warranty does the Canadian Solar CS6R 420W include?
It comes with a 12-year product warranty and a 25-year performance warranty guaranteeing output at approximately 86.5% of rated power at the end of the warranty period.
How does the Canadian Solar CS6R 420W perform in hot weather?
With a temperature coefficient of -0.34%/°C, the CS6R 420W experiences moderate power reduction in high temperatures. Every degree above 25°C reduces output by 0.34%.
What size system can I build with the Canadian Solar CS6R 420W?
At 420W per panel, you would need approximately 20 panels for an 8 kW system or 24 panels for a 10 kW system. Each panel measures 1722 x 1134 mm (21.0 sq ft).
What inverter is best with the Canadian Solar CS6R 420W?
The Canadian Solar CS6R 420W works well with both string inverters and microinverters. For string inverters, choose one with a maximum input voltage above 40.5V and an MPPT voltage range that covers 33.8V. Microinverters rated for 420W+ panels are also an excellent choice, offering panel-level monitoring and shade tolerance. Popular options include Enphase IQ8 series microinverters and SolarEdge string inverters with power optimizers.
How long will the Canadian Solar CS6R 420W last?
The Canadian Solar CS6R 420W is built to last well beyond its 25-year performance warranty. With first-year degradation of 1.5% and annual degradation of 0.5% thereafter, the panel will still produce approximately 86.5% of its rated power after 25 years. Most modern solar panels continue generating useful power for 30-40 years, though output gradually decreases over time.
Is the Canadian Solar CS6R 420W good for Arizona and other sunny states?
The Canadian Solar CS6R 420W can work in hot states like Arizona, Nevada, and Texas, though its temperature coefficient of -0.34%/°C means it will lose some output on the hottest days. Consider panels with a lower (closer to 0) temperature coefficient if you live in an area with extreme heat. Higher sun exposure in these states means more total energy production throughout the year, often offsetting any heat-related losses.
Is the Canadian Solar CS6R 420W worth the money?
The Canadian Solar CS6R 420W delivers 21% efficiency, which is near the industry average of ~21%. Combined with a standard 12-year product warranty and 25-year performance guarantee, it offers strong value for homeowners seeking reliable solar generation.
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Last updated: February 2026