Q CELLS Q.PEAK DUO 370W vs Panasonic EVPV400H
The Panasonic EVPV400H wins this comparison by a decisive margin. It leads in efficiency (21.2% vs 20.4%) and matches or exceeds on warranty (25 vs 12 years). For most residential installations, the Panasonic EVPV400H is the stronger choice.
Key Differences
- • Q CELLS Q.PEAK DUO 370W is rated at 370W while Panasonic EVPV400H is rated at 400W, a 30W difference.
- • Panasonic EVPV400H achieves 21.2% efficiency vs 20.4% for the other, a 0.8 percentage point gap.
- • Panasonic EVPV400H comes with a 25-year product warranty vs 12 years for the other.
- • Panasonic EVPV400H has a superior temperature coefficient of -0.26%/°C vs -0.35%/°C, retaining more power in hot climates.
- • Q CELLS Q.PEAK DUO 370W uses PERC Mono cells while Panasonic EVPV400H uses HJT (Heterojunction) cells, representing different technology generations.
Specifications Breakdown
Module Efficiency
The Panasonic EVPV400H achieves 21.2% module efficiency compared to Q CELLS Q.PEAK DUO 370W's 20.4%, meaning Panasonic EVPV400H converts 0.8 percentage points more sunlight into electricity per square meter. In practical terms, the Q CELLS Q.PEAK DUO 370W produces 189.5 watts per square meter of panel area while the Panasonic EVPV400H produces 204.8 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 Panasonic EVPV400H delivers 400W per panel versus 370W for the Q CELLS Q.PEAK DUO 370W, a 30W difference per module. To build an 8 kW residential system, you would need 22 Q CELLS Q.PEAK DUO 370W panels or 20 Panasonic EVPV400H panels. Choosing the higher-wattage option saves 2 panels, 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 Panasonic EVPV400H has a temperature coefficient of -0.26%/°C versus -0.35%/°C for the Q CELLS Q.PEAK DUO 370W. On a hot summer day when cell temperature reaches 65°C (40°C above the 25°C STC baseline), the Panasonic EVPV400H retains 94.8% of its rated power while the other retains 93.0%. 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 Q CELLS Q.PEAK DUO 370W is backed by a 12-year product warranty and 25-year performance guarantee, while the Panasonic EVPV400H offers 25-year product and 25-year performance coverage. The Panasonic EVPV400H provides 13 additional years of defect protection, covering manufacturing issues, material failures, and premature performance loss. Based on their published degradation rates (1% first year then 0.4%/year for Q CELLS Q.PEAK DUO 370W; 0.5% first year then 0.35%/year for Panasonic EVPV400H), after 25 years the Q CELLS Q.PEAK DUO 370W should retain approximately 89.4% of original output versus 91.1% for the Panasonic EVPV400H. This 1.7 percentage point gap in end-of-life output meaningfully impacts lifetime energy economics.
Physical Dimensions & Weight
The Q CELLS Q.PEAK DUO 370W measures 1722×1134×30mm and weighs 19.5 kg, while the Panasonic EVPV400H measures 1722×1134×30mm at 21 kg. 1.95 m² of panel area for the Q CELLS Q.PEAK DUO 370W versus 1.95 m² for the Panasonic EVPV400H. Their weights are closely matched, so neither panel imposes a significantly different structural load on the mounting system. Similar footprints mean both panels fit comparably on standard residential rooftop configurations.
Specification Comparison
| Specification | Q CELLS Q.PEAK DUO 370W | Panasonic EVPV400H |
|---|---|---|
| Power | 370W | 400W |
| Efficiency | 20.4% | 21.2% |
| Power Density | 17.6 W/sq ft | 19.0 W/sq ft |
| Cell Type | PERC Mono | HJT (Heterojunction) |
| Bifacial | No | Yes |
| Weight | 19.5 kg | 21 kg |
| Temp Coefficient | -0.35%/°C | -0.26%/°C |
| Snow Load | 5400 Pa | 5400 Pa |
| Wind Load | 3600 Pa | 2400 Pa |
| Product Warranty | 12 years | 25 years |
| Performance Warranty | 25 years | 25 years |
| Degradation (Year 1) | 1% | 0.5% |
| Annual Degradation | 0.4% | 0.35% |
| Country | Malaysia | Japan |
5-Dimension Head-to-Head Analysis
1. Efficiency & Power Density
Winner: Panasonic EVPV400HThe Panasonic EVPV400H achieves 21.2% efficiency versus 20.4% — a 0.8 percentage point advantage. On a typical 30-panel residential roof, this translates to approximately 0.9 kW more total system capacity, or 5 kWh more annual production in an average US location.
2. Hot Climate Performance
Winner: Panasonic EVPV400HThe Panasonic EVPV400H has a better temperature coefficient of -0.26%/°C versus -0.35%/°C. On a 45°C summer day (20°C above STC), the winner retains 94.8% of rated power versus 93.0%. This is a meaningful difference in hot states like Arizona, Texas, and Florida.
3. Durability & Warranty
Winner: Panasonic EVPV400HPanasonic EVPV400H leads with a 25-year product warranty versus 12 years. Panasonic EVPV400H degrades more slowly at 0.35% per year versus 0.4%. After 25 years, expect 89.4% vs 91.1% of original output for Q CELLS Q.PEAK DUO 370W and Panasonic EVPV400H respectively.
4. Power Output
Winner: Panasonic EVPV400HThe Panasonic EVPV400H delivers 400W versus 370W per panel — 30W more. For an 8 kW system, you need 20 panels with the higher-wattage option versus 22 panels, saving 2 panels and the associated racking and labor costs.
5. Cell Technology
Winner: Panasonic EVPV400HThe Q CELLS Q.PEAK DUO 370W uses PERC Mono: PERC (Passivated Emitter Rear Cell) is the current mainstream technology, offering good efficiency at the lowest manufacturing cost. The Panasonic EVPV400H uses HJT (Heterojunction): HJT (Heterojunction) combines crystalline silicon with amorphous silicon layers, delivering the best temperature coefficient and bifacial gains, but at higher manufacturing cost. HJT (Heterojunction) represents a newer generation technology with a longer performance runway as manufacturing matures.
Q CELLS Q.PEAK DUO 370W
The Q.PEAK DUO is an entry-level PERC panel from Q CELLS offering 370W with solid quality at a more accessible price point.
Pros
- + Q CELLS quality at lower cost
- + Lightweight design
- + Proven half-cut cell design
- + Available worldwide
Cons
- - Lower wattage
- - Standard PERC efficiency
- - Shorter product warranty
Panasonic EVPV400H
DISCONTINUED: Panasonic exited solar manufacturing in 2023. The EVPV400H was Panasonic's standard HJT residential panel, delivering 400W with the brand's signature quality and longevity.
Pros
- + Panasonic reliability
- + HJT advantages
- + Solid 25-year warranty
- + Good all-round performer
Cons
- - DISCONTINUED - no longer manufactured
- - No new units available
- - No ongoing product support
Choose Q CELLS Q.PEAK DUO 370W If...
- ✓ Budget installations wanting Q CELLS quality at an entry-level price.
Choose Panasonic EVPV400H 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 25+ 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
Our Recommendation
The Panasonic EVPV400H is the decisive winner in this solar panel comparison, outperforming the Q CELLS Q.PEAK DUO 370W in 5 of 5 dimensions. Unless you have a specific requirement that the Q CELLS Q.PEAK DUO 370W uniquely addresses, the Panasonic EVPV400H is the stronger choice for virtually every installation scenario.
Frequently Asked Questions
Which is better, Q CELLS Q.PEAK DUO 370W or Panasonic EVPV400H?
The Panasonic EVPV400H wins this comparison by a decisive margin. It leads in efficiency (21.2% vs 20.4%) and matches or exceeds on warranty (25 vs 12 years). For most residential installations, the Panasonic EVPV400H is the stronger choice.
Which panel is more efficient, Q CELLS Q.PEAK DUO 370W or Panasonic EVPV400H?
The Panasonic EVPV400H at 21.2% module efficiency. Higher efficiency means more watts per square foot of roof space, which is critical for space-constrained installations. The difference of 0.8 percentage points translates to approximately 30W per panel under standard test conditions.
Which has a better warranty, Q CELLS Q.PEAK DUO 370W or Panasonic EVPV400H?
The Q CELLS Q.PEAK DUO 370W comes with a 12-year product warranty and 25-year performance guarantee. The Panasonic EVPV400H offers 25-year product and 25-year performance warranties. Panasonic EVPV400H provides 13 additional years of product coverage.
Which panel performs better in hot weather?
The Q CELLS Q.PEAK DUO 370W has a temperature coefficient of -0.35%/°C and the Panasonic EVPV400H is -0.26%/°C. Panasonic EVPV400H retains more power in heat — important in states like Arizona, Texas, and Florida. A lower (less negative) temperature coefficient is better.
How many Q CELLS Q.PEAK DUO 370W vs Panasonic EVPV400H panels do I need for an 8 kW system?
For an 8 kW system: you need 22 Q CELLS Q.PEAK DUO 370W panels (370W each) or 20 Panasonic EVPV400H panels (400W each). The Panasonic EVPV400H requires fewer panels, saving on racking hardware and installation labor.
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Last updated: February 2026