First Solar — US
Series 4 420W C Pro
The First Solar Series 4 420W C Pro is a 420W CdTe solar panel with 18.7% efficiency. Made in US. Backed by a 25-year warranty.
Premium Tier🇺🇸 Domestic Content Bonus Eligible
420W
Wattage
18.7%
Efficiency
CdTe
Cell Type
25 years
Warranty
Full Specifications
- Brand
- First Solar
- Model
- Series 4 420W C Pro
- Series
- Series 4
- Wattage
- 420W
- Module Efficiency
- 18.7%
- Cell Type
- CdTe
- Dimensions
- 66-80" x 39-41"
- Weight
- 48 lbs
- Warranty
- 25 years
- Est. Price Per Watt
- $2.85
- Est. 7kW System Cost
- $19,950
- Est. 10kW System Cost
- $28,500
- Temperature Coefficient
- -0.25%/°C
- Bifacial
- No
- Origin
- US
- FEOC Status
- pass
Other First Solar Panels
| Model | Wattage | Efficiency | Cell | $/W |
|---|---|---|---|---|
| Series 6 475W E Pro | 475W | 20.5% | CdTe | $3.75 |
| Series 7 475W E Pro | 475W | 20.5% | CdTe | $3.75 |
| Series 4 475W E Pro | 475W | 20.5% | CdTe | $3.75 |
| Series 5 475W E Pro | 475W | 20.5% | CdTe | $3.75 |
| Series 6 465W D Plus | 465W | 20.2% | CdTe | $3.60 |
Similar Wattage Panels (Competitors)
| Panel | Wattage | Efficiency | $/W |
|---|---|---|---|
| Maxeon Maxeon 3 450W D Plus | 450W | 23.3% | $4.61 |
| Maxeon Maxeon 6 450W D Plus | 450W | 23.3% | $4.61 |
| Maxeon Maxeon 7 450W D Plus | 450W | 23.3% | $4.61 |
| Maxeon Maxeon Air 450W D Plus | 450W | 23.3% | $4.61 |
Frequently Asked Questions
How much does a 420W First Solar Series 4 420W C Pro cost?
The First Solar Series 4 420W C Pro costs approximately $1197 per panel ($$2.85/W). A typical 7kW system using this panel would cost around $19,950 before incentives.
⚠ The 30% Federal Solar Tax Credit (48E/ITC) expired July 4, 2026.
Selecting 30% ITC assumes you began construction before this deadline. Most new purchases no longer qualify.Learn about your options after the deadline →
Is the First Solar Series 4 420W C Pro a good solar panel?
The First Solar Series 4 420W C Pro has 18.7% efficiency and a 25 years warranty, placing it in the premium tier. This is a solid mid-range panel suitable for most residential installations. It also qualifies for the domestic content bonus under the Inflation Reduction Act.
How many First Solar Series 4 420W C Pro panels do I need?
For a typical 7kW residential system, you'd need approximately 17 panels. For a 10kW system, plan for about 24 panels. The exact number depends on your roof space, energy usage, and local sun hours.