SunPower — US
X-Series 420W B Silver
The SunPower X-Series 420W B Silver is a 420W IBC solar panel with 22.2% efficiency. Made in US. Backed by a 25-year warranty.
Premium Tier🇺🇸 Domestic Content Bonus Eligible
420W
Wattage
22.2%
Efficiency
IBC
Cell Type
25 years
Warranty
Full Specifications
- Brand
- SunPower
- Model
- X-Series 420W B Silver
- Series
- X-Series
- Wattage
- 420W
- Module Efficiency
- 22.2%
- Cell Type
- IBC
- Dimensions
- 66-80" x 39-41"
- Weight
- 48 lbs
- Warranty
- 25 years
- Est. Price Per Watt
- $4.21
- Est. 7kW System Cost
- $29,470
- Est. 10kW System Cost
- $42,100
- Temperature Coefficient
- -0.25%/°C
- Bifacial
- No
- Origin
- US
- FEOC Status
- pass
Other SunPower Panels
| Model | Wattage | Efficiency | Cell | $/W |
|---|---|---|---|---|
| Maxeon 455W E Pro | 455W | 23.4% | IBC | $4.71 |
| Performance 455W E Pro | 455W | 23.4% | IBC | $4.71 |
| X-Series 455W E Pro | 455W | 23.4% | IBC | $4.71 |
| E-Series 455W E Pro | 455W | 23.4% | IBC | $4.71 |
| P-Series 455W E Pro | 455W | 23.4% | IBC | $4.71 |
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 SunPower X-Series 420W B Silver cost?
The SunPower X-Series 420W B Silver costs approximately $1768 per panel ($$4.21/W). A typical 7kW system using this panel would cost around $29,470 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 SunPower X-Series 420W B Silver a good solar panel?
The SunPower X-Series 420W B Silver has 22.2% efficiency and a 25 years warranty, placing it in the premium tier. This is above-average efficiency, making it a strong choice. It also qualifies for the domestic content bonus under the Inflation Reduction Act.
How many SunPower X-Series 420W B Silver 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.