Maxeon Maxeon 6 425W vs First Solar Series 6 Plus 465W
The Maxeon Maxeon 6 425W wins this comparison by a decisive margin. It leads in efficiency (22.2% vs 19.2%) and matches or exceeds on warranty (40 vs 10 years). For most residential installations, the Maxeon Maxeon 6 425W is the stronger choice.
Key Differences
- • Maxeon Maxeon 6 425W is rated at 425W while First Solar Series 6 Plus 465W is rated at 465W, a 40W difference.
- • Maxeon Maxeon 6 425W achieves 22.2% efficiency vs 19.2% for the other, a 3.0 percentage point gap.
- • Maxeon Maxeon 6 425W comes with a 40-year product warranty vs 10 years for the other.
- • Maxeon Maxeon 6 425W has a superior temperature coefficient of -0.27%/°C vs -0.28%/°C, retaining more power in hot climates.
- • Maxeon Maxeon 6 425W uses IBC (Interdigitated Back Contact) cells while First Solar Series 6 Plus 465W uses CdTe (Cadmium Telluride) cells, representing different technology generations.
Specifications Breakdown
Module Efficiency
The Maxeon Maxeon 6 425W achieves 22.2% module efficiency compared to First Solar Series 6 Plus 465W's 19.2%, meaning Maxeon Maxeon 6 425W converts 3.0 percentage points more sunlight into electricity per square meter. In practical terms, the Maxeon Maxeon 6 425W produces 220.0 watts per square meter of panel area while the First Solar Series 6 Plus 465W produces 187.9 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 First Solar Series 6 Plus 465W delivers 465W per panel versus 425W for the Maxeon Maxeon 6 425W, a 40W difference per module. To build an 8 kW residential system, you would need 19 Maxeon Maxeon 6 425W panels or 18 First Solar Series 6 Plus 465W 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 Maxeon Maxeon 6 425W has a temperature coefficient of -0.27%/°C versus -0.28%/°C for the First Solar Series 6 Plus 465W. On a hot summer day when cell temperature reaches 65°C (40°C above the 25°C STC baseline), the Maxeon Maxeon 6 425W retains 94.6% of its rated power while the other retains 94.4%. 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 Maxeon Maxeon 6 425W is backed by a 40-year product warranty and 40-year performance guarantee, while the First Solar Series 6 Plus 465W offers 10-year product and 30-year performance coverage. The Maxeon Maxeon 6 425W provides 30 additional years of defect protection, covering manufacturing issues, material failures, and premature performance loss. Based on their published degradation rates (0.25% first year then 0.25%/year for Maxeon Maxeon 6 425W; 1.5% first year then 0.5%/year for First Solar Series 6 Plus 465W), after 25 years the Maxeon Maxeon 6 425W should retain approximately 93.8% of original output versus 86.5% for the First Solar Series 6 Plus 465W. This 7.3 percentage point gap in end-of-life output meaningfully impacts lifetime energy economics.
Physical Dimensions & Weight
The Maxeon Maxeon 6 425W measures 1872×1032×30mm and weighs 20.5 kg, while the First Solar Series 6 Plus 465W measures 2009×1232×49mm at 34.5 kg. 1.93 m² of panel area for the Maxeon Maxeon 6 425W versus 2.48 m² for the First Solar Series 6 Plus 465W. The Maxeon Maxeon 6 425W is 14.0 kg lighter per panel, which reduces structural load requirements on the roof and makes handling easier during installation. For a 20-panel system, that is a total weight difference of 280 kg. The more compact Maxeon Maxeon 6 425W may be easier to fit on irregularly shaped or space-limited rooftops.
Specification Comparison
| Specification | Maxeon Maxeon 6 425W | First Solar Series 6 Plus 465W |
|---|---|---|
| Power | 425W | 465W |
| Efficiency | 22.2% | 19.2% |
| Power Density | 20.4 W/sq ft | 17.5 W/sq ft |
| Cell Type | IBC (Interdigitated Back Contact) | CdTe (Cadmium Telluride) |
| Bifacial | Yes | No |
| Weight | 20.5 kg | 34.5 kg |
| Temp Coefficient | -0.27%/°C | -0.28%/°C |
| Snow Load | 5400 Pa | 5400 Pa |
| Wind Load | 3600 Pa | 4000 Pa |
| Product Warranty | 40 years | 10 years |
| Performance Warranty | 40 years | 30 years |
| Degradation (Year 1) | 0.25% | 1.5% |
| Annual Degradation | 0.25% | 0.5% |
| Country | Malaysia | United States |
5-Dimension Head-to-Head Analysis
1. Efficiency & Power Density
Winner: Maxeon Maxeon 6 425WThe Maxeon Maxeon 6 425W achieves 22.2% efficiency versus 19.2% — a 3.0 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: Maxeon Maxeon 6 425WThe Maxeon Maxeon 6 425W has a better temperature coefficient of -0.27%/°C versus -0.28%/°C. On a 45°C summer day (20°C above STC), the winner retains 94.6% of rated power versus 94.4%. The difference is modest but accumulates over 25 years of summer production.
3. Durability & Warranty
Winner: Maxeon Maxeon 6 425WMaxeon Maxeon 6 425W leads with a 40-year product warranty versus 10 years. Maxeon Maxeon 6 425W degrades more slowly at 0.25% per year versus 0.5%. After 25 years, expect 93.8% vs 86.5% of original output for Maxeon Maxeon 6 425W and First Solar Series 6 Plus 465W respectively.
4. Power Output
Winner: First Solar Series 6 Plus 465WThe First Solar Series 6 Plus 465W delivers 465W versus 425W per panel — 40W more. For an 8 kW system, you need 18 panels with the higher-wattage option versus 19 panels, saving 1 panels and the associated racking and labor costs.
5. Cell Technology
Winner: Maxeon Maxeon 6 425WThe Maxeon Maxeon 6 425W uses IBC (Interdigitated Back Contact): IBC (Interdigitated Back Contact) moves all electrical contacts to the rear of the cell, maximizing front-side light capture for the highest possible efficiency. The First Solar Series 6 Plus 465W uses CdTe (Cadmium Telluride): CdTe (Cadmium Telluride). IBC (Interdigitated Back Contact) represents a newer generation technology with a longer performance runway as manufacturing matures.
Maxeon Maxeon 6 425W
The Maxeon 6 delivers 425W with 22.2% efficiency and the same industry-leading 40-year warranty as the Maxeon 7 series.
Pros
- + 40-year complete warranty
- + 22.2% IBC efficiency
- + Excellent aesthetics
- + Ultra-low degradation
Cons
- - Very high cost per watt
- - Limited installer network
- - Fewer wattage options
First Solar Series 6 Plus 465W
The Series 6 Plus delivers 465W using First Solar's proven CdTe thin-film technology, manufactured in the United States.
Pros
- + Proven US thin-film technology
- + Excellent temperature coefficient
- + Environmentally responsible
- + Strong bankability
Cons
- - Lower efficiency
- - Very heavy panel
- - Not suitable for residential
Choose Maxeon Maxeon 6 425W If...
- ✓ Your roof space is limited and you need maximum power per panel
- ✓ Long-term warranty protection is a top priority and you plan to stay in your home for 40+ years
- ✓ You live in a hot climate (Arizona, Texas, Florida) where heat performance matters
- ✓ You want maximum output retention over the system's 25-30 year lifespan
- ✓ Homeowners seeking a premium panel with the longest warranty available.
Choose First Solar Series 6 Plus 465W If...
- ✓ You want fewer panels to reach your target system size, reducing racking and labor costs
- ✓ Large commercial and utility projects wanting proven US thin-film technology.
Our Recommendation
The Maxeon Maxeon 6 425W is the decisive winner in this solar panel comparison, outperforming the First Solar Series 6 Plus 465W in 4 of 5 dimensions. Unless you have a specific requirement that the First Solar Series 6 Plus 465W uniquely addresses, the Maxeon Maxeon 6 425W is the stronger choice for virtually every installation scenario.
Frequently Asked Questions
Which is better, Maxeon Maxeon 6 425W or First Solar Series 6 Plus 465W?
The Maxeon Maxeon 6 425W wins this comparison by a decisive margin. It leads in efficiency (22.2% vs 19.2%) and matches or exceeds on warranty (40 vs 10 years). For most residential installations, the Maxeon Maxeon 6 425W is the stronger choice.
Which panel is more efficient, Maxeon Maxeon 6 425W or First Solar Series 6 Plus 465W?
The Maxeon Maxeon 6 425W at 22.2% module efficiency. Higher efficiency means more watts per square foot of roof space, which is critical for space-constrained installations. The difference of 3.0 percentage points translates to approximately 40W per panel under standard test conditions.
Which has a better warranty, Maxeon Maxeon 6 425W or First Solar Series 6 Plus 465W?
The Maxeon Maxeon 6 425W comes with a 40-year product warranty and 40-year performance guarantee. The First Solar Series 6 Plus 465W offers 10-year product and 30-year performance warranties. Maxeon Maxeon 6 425W provides 30 additional years of product coverage.
Which panel performs better in hot weather?
The Maxeon Maxeon 6 425W has a temperature coefficient of -0.27%/°C and the First Solar Series 6 Plus 465W is -0.28%/°C. Maxeon Maxeon 6 425W retains more power in heat — important in states like Arizona, Texas, and Florida. A lower (less negative) temperature coefficient is better.
How many Maxeon Maxeon 6 425W vs First Solar Series 6 Plus 465W panels do I need for an 8 kW system?
For an 8 kW system: you need 19 Maxeon Maxeon 6 425W panels (425W each) or 18 First Solar Series 6 Plus 465W panels (465W each). The First Solar Series 6 Plus 465W requires fewer panels, saving on racking hardware and installation labor.
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Last updated: February 2026