First Solar Series 7 545W vs Yingli Solar YLM 144 Cell 550W
The Yingli Solar YLM 144 Cell 550W wins this comparison by a clear margin. It leads in efficiency (21.3% vs 19.8%) and matches or exceeds on warranty (12 vs 10 years). For most residential installations, the Yingli Solar YLM 144 Cell 550W is the stronger choice.
Key Differences
- • First Solar Series 7 545W is rated at 545W while Yingli Solar YLM 144 Cell 550W is rated at 550W, a 5W difference.
- • Yingli Solar YLM 144 Cell 550W achieves 21.3% efficiency vs 19.8% for the other, a 1.5 percentage point gap.
- • Yingli Solar YLM 144 Cell 550W comes with a 12-year product warranty vs 10 years for the other.
- • First Solar Series 7 545W has a superior temperature coefficient of -0.28%/°C vs -0.34%/°C, retaining more power in hot climates.
- • First Solar Series 7 545W uses CdTe (Cadmium Telluride) cells while Yingli Solar YLM 144 Cell 550W uses PERC Mono cells, representing different technology generations.
Specifications Breakdown
Module Efficiency
The Yingli Solar YLM 144 Cell 550W achieves 21.3% module efficiency compared to First Solar Series 7 545W's 19.8%, meaning Yingli Solar YLM 144 Cell 550W converts 1.5 percentage points more sunlight into electricity per square meter. In practical terms, the First Solar Series 7 545W produces 173.9 watts per square meter of panel area while the Yingli Solar YLM 144 Cell 550W produces 212.9 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 Yingli Solar YLM 144 Cell 550W delivers 550W per panel versus 545W for the First Solar Series 7 545W, a 5W difference per module. To build an 8 kW residential system, you would need 15 First Solar Series 7 545W panels or 15 Yingli Solar YLM 144 Cell 550W 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
The First Solar Series 7 545W has a temperature coefficient of -0.28%/°C versus -0.34%/°C for the Yingli Solar YLM 144 Cell 550W. On a hot summer day when cell temperature reaches 65°C (40°C above the 25°C STC baseline), the First Solar Series 7 545W retains 94.4% of its rated power while the other retains 93.2%. This difference is particularly significant in hot climates such as the American Southwest, the Middle East, and Southeast Asia, where panels routinely operate 30-40°C above STC for several hours each day. Over the system lifetime, the cumulative energy advantage from a better temperature coefficient can amount to 2-4% of total production.
Warranty Coverage
The First Solar Series 7 545W is backed by a 10-year product warranty and 30-year performance guarantee, while the Yingli Solar YLM 144 Cell 550W offers 12-year product and 25-year performance coverage. The Yingli Solar YLM 144 Cell 550W provides 2 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 First Solar Series 7 545W; 1.5% first year then 0.5%/year for Yingli Solar YLM 144 Cell 550W), after 25 years the First Solar Series 7 545W should retain approximately 86.5% of original output versus 86.5% for the Yingli Solar YLM 144 Cell 550W. The end-of-life output levels are closely matched.
Physical Dimensions & Weight
The First Solar Series 7 545W measures 2520×1244×49mm and weighs 38 kg, while the Yingli Solar YLM 144 Cell 550W measures 2278×1134×35mm at 28.5 kg. 3.13 m² of panel area for the First Solar Series 7 545W versus 2.58 m² for the Yingli Solar YLM 144 Cell 550W. The Yingli Solar YLM 144 Cell 550W is 9.5 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 190 kg. The more compact Yingli Solar YLM 144 Cell 550W may be easier to fit on irregularly shaped or space-limited rooftops.
Specification Comparison
| Specification | First Solar Series 7 545W | Yingli Solar YLM 144 Cell 550W |
|---|---|---|
| Power | 545W | 550W |
| Efficiency | 19.8% | 21.3% |
| Power Density | 16.2 W/sq ft | 19.8 W/sq ft |
| Cell Type | CdTe (Cadmium Telluride) | PERC Mono |
| Bifacial | No | No |
| Weight | 38 kg | 28.5 kg |
| Temp Coefficient | -0.28%/°C | -0.34%/°C |
| Snow Load | 5400 Pa | 5400 Pa |
| Wind Load | 4000 Pa | 2400 Pa |
| Product Warranty | 10 years | 12 years |
| Performance Warranty | 30 years | 25 years |
| Degradation (Year 1) | 1.5% | 1.5% |
| Annual Degradation | 0.5% | 0.5% |
| Country | United States | China |
5-Dimension Head-to-Head Analysis
1. Efficiency & Power Density
Winner: Yingli Solar YLM 144 Cell 550WThe Yingli Solar YLM 144 Cell 550W achieves 21.3% efficiency versus 19.8% — a 1.5 percentage point advantage. On a typical 30-panel residential roof, this translates to approximately 0.1 kW more total system capacity, or 1 kWh more annual production in an average US location.
2. Hot Climate Performance
Winner: First Solar Series 7 545WThe First Solar Series 7 545W has a better temperature coefficient of -0.28%/°C versus -0.34%/°C. On a 45°C summer day (20°C above STC), the winner retains 94.4% of rated power versus 93.2%. This is a meaningful difference in hot states like Arizona, Texas, and Florida.
3. Durability & Warranty
Winner: Yingli Solar YLM 144 Cell 550WYingli Solar YLM 144 Cell 550W leads with a 12-year product warranty versus 10 years. After 25 years, expect 86.5% vs 86.5% of original output for First Solar Series 7 545W and Yingli Solar YLM 144 Cell 550W respectively.
4. Power Output
Winner: Yingli Solar YLM 144 Cell 550WThe Yingli Solar YLM 144 Cell 550W delivers 550W versus 545W per panel — 5W more. For an 8 kW system, you need 15 panels with the higher-wattage option versus 15 panels, saving 0 panels and the associated racking and labor costs.
5. Cell Technology
Winner: First Solar Series 7 545WThe First Solar Series 7 545W uses CdTe (Cadmium Telluride): CdTe (Cadmium Telluride). The Yingli Solar YLM 144 Cell 550W uses PERC Mono: PERC (Passivated Emitter Rear Cell) is the current mainstream technology, offering good efficiency at the lowest manufacturing cost. CdTe (Cadmium Telluride) represents a newer generation technology with a longer performance runway as manufacturing matures.
First Solar Series 7 545W
First Solar Series 7 is a US-made thin-film CdTe module delivering 545W with superior temperature performance and sustainable manufacturing.
Pros
- + US manufactured thin-film
- + Excellent hot weather performance
- + Lower carbon footprint
- + No supply chain issues
Cons
- - Lower efficiency than crystalline silicon
- - Very large and heavy
- - Not for residential roofs
Yingli Solar YLM 144 Cell 550W
Yingli Solar YLM 144 Cell is a high-output PERC module for commercial installations at a competitive price point.
Pros
- + High 550W output
- + Competitive commercial pricing
- + Proven track record
- + Large format
Cons
- - Older PERC technology
- - Heavy panel
- - Brand perception concerns
Choose First Solar Series 7 545W If...
- ✓ You live in a hot climate (Arizona, Texas, Florida) where heat performance matters
- ✓ Utility-scale projects valuing US manufacturing and hot-climate performance.
Choose Yingli Solar YLM 144 Cell 550W 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
- ✓ Long-term warranty protection is a top priority and you plan to stay in your home for 12+ years
- ✓ Commercial projects seeking affordable high-output PERC modules.
Our Recommendation
We recommend the Yingli Solar YLM 144 Cell 550W for most buyers in this comparison. It wins 3 of 5 key dimensions and offers a clear advantage in the metrics that matter most for a solar panel purchase. The First Solar Series 7 545W remains a good product, but the Yingli Solar YLM 144 Cell 550W delivers better overall value for the majority of installations.
Frequently Asked Questions
Which is better, First Solar Series 7 545W or Yingli Solar YLM 144 Cell 550W?
The Yingli Solar YLM 144 Cell 550W wins this comparison by a clear margin. It leads in efficiency (21.3% vs 19.8%) and matches or exceeds on warranty (12 vs 10 years). For most residential installations, the Yingli Solar YLM 144 Cell 550W is the stronger choice.
Which panel is more efficient, First Solar Series 7 545W or Yingli Solar YLM 144 Cell 550W?
The Yingli Solar YLM 144 Cell 550W at 21.3% module efficiency. Higher efficiency means more watts per square foot of roof space, which is critical for space-constrained installations. The difference of 1.5 percentage points translates to approximately 5W per panel under standard test conditions.
Which has a better warranty, First Solar Series 7 545W or Yingli Solar YLM 144 Cell 550W?
The First Solar Series 7 545W comes with a 10-year product warranty and 30-year performance guarantee. The Yingli Solar YLM 144 Cell 550W offers 12-year product and 25-year performance warranties. Yingli Solar YLM 144 Cell 550W provides 2 additional years of product coverage.
Which panel performs better in hot weather?
The First Solar Series 7 545W has a temperature coefficient of -0.28%/°C and the Yingli Solar YLM 144 Cell 550W is -0.34%/°C. First Solar Series 7 545W retains more power in heat — important in states like Arizona, Texas, and Florida. A lower (less negative) temperature coefficient is better.
How many First Solar Series 7 545W vs Yingli Solar YLM 144 Cell 550W panels do I need for an 8 kW system?
For an 8 kW system: you need 15 First Solar Series 7 545W panels (545W each) or 15 Yingli Solar YLM 144 Cell 550W panels (550W each). The Yingli Solar YLM 144 Cell 550W requires fewer panels, saving on racking hardware and installation labor.
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Last updated: February 2026