LONGi Hi-MO 7 590W vs Waaree WS-545 Bifacial
The LONGi Hi-MO 7 590W wins this comparison by a clear margin. It leads in efficiency (22.8% vs 21.2%) and matches or exceeds on warranty (12 vs 12 years). For most residential installations, the LONGi Hi-MO 7 590W is the stronger choice.
Key Differences
- • LONGi Hi-MO 7 590W is rated at 590W while Waaree WS-545 Bifacial is rated at 545W, a 45W difference.
- • LONGi Hi-MO 7 590W achieves 22.8% efficiency vs 21.2% for the other, a 1.6 percentage point gap.
- • Both carry matching 12-year product warranties.
- • LONGi Hi-MO 7 590W has a superior temperature coefficient of -0.28%/°C vs -0.3%/°C, retaining more power in hot climates.
- • LONGi Hi-MO 7 590W uses HPBC (Back Contact N-type) cells while Waaree WS-545 Bifacial uses TOPCon N-type Bifacial cells, representing different technology generations.
Specifications Breakdown
Module Efficiency
The LONGi Hi-MO 7 590W achieves 22.8% module efficiency compared to Waaree WS-545 Bifacial's 21.2%, meaning LONGi Hi-MO 7 590W converts 1.6 percentage points more sunlight into electricity per square meter. In practical terms, the LONGi Hi-MO 7 590W produces 228.4 watts per square meter of panel area while the Waaree WS-545 Bifacial produces 211.0 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 LONGi Hi-MO 7 590W delivers 590W per panel versus 545W for the Waaree WS-545 Bifacial, a 45W difference per module. To build an 8 kW residential system, you would need 14 LONGi Hi-MO 7 590W panels or 15 Waaree WS-545 Bifacial 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 LONGi Hi-MO 7 590W has a temperature coefficient of -0.28%/°C versus -0.3%/°C for the Waaree WS-545 Bifacial. On a hot summer day when cell temperature reaches 65°C (40°C above the 25°C STC baseline), the LONGi Hi-MO 7 590W retains 94.4% of its rated power while the other retains 94.0%. 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 LONGi Hi-MO 7 590W is backed by a 12-year product warranty and 30-year performance guarantee, while the Waaree WS-545 Bifacial offers 12-year product and 30-year performance coverage. Both offer identical product warranty duration. Based on their published degradation rates (1% first year then 0.4%/year for LONGi Hi-MO 7 590W; 1% first year then 0.4%/year for Waaree WS-545 Bifacial), after 25 years the LONGi Hi-MO 7 590W should retain approximately 89.4% of original output versus 89.4% for the Waaree WS-545 Bifacial. The end-of-life output levels are closely matched.
Physical Dimensions & Weight
The LONGi Hi-MO 7 590W measures 2278×1134×35mm and weighs 28.8 kg, while the Waaree WS-545 Bifacial measures 2278×1134×35mm at 28 kg. 2.58 m² of panel area for the LONGi Hi-MO 7 590W versus 2.58 m² for the Waaree WS-545 Bifacial. 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 | LONGi Hi-MO 7 590W | Waaree WS-545 Bifacial |
|---|---|---|
| Power | 590W | 545W |
| Efficiency | 22.8% | 21.2% |
| Power Density | 21.2 W/sq ft | 19.6 W/sq ft |
| Cell Type | HPBC (Back Contact N-type) | TOPCon N-type Bifacial |
| Bifacial | Yes | Yes |
| Weight | 28.8 kg | 28 kg |
| Temp Coefficient | -0.28%/°C | -0.3%/°C |
| Snow Load | 5400 Pa | 5400 Pa |
| Wind Load | 2400 Pa | 2400 Pa |
| Product Warranty | 12 years | 12 years |
| Performance Warranty | 30 years | 30 years |
| Degradation (Year 1) | 1% | 1% |
| Annual Degradation | 0.4% | 0.4% |
| Country | China | India |
5-Dimension Head-to-Head Analysis
1. Efficiency & Power Density
Winner: LONGi Hi-MO 7 590WThe LONGi Hi-MO 7 590W achieves 22.8% efficiency versus 21.2% — a 1.6 percentage point advantage. On a typical 30-panel residential roof, this translates to approximately 1.4 kW more total system capacity, or 7 kWh more annual production in an average US location.
2. Hot Climate Performance
Winner: LONGi Hi-MO 7 590WThe LONGi Hi-MO 7 590W has a better temperature coefficient of -0.28%/°C versus -0.3%/°C. On a 45°C summer day (20°C above STC), the winner retains 94.4% of rated power versus 94.0%. The difference is modest but accumulates over 25 years of summer production.
3. Durability & Warranty
Winner: TieBoth panels offer identical 12-year product warranties and 0.4% annual degradation. Neither has a durability advantage.
4. Power Output
Winner: LONGi Hi-MO 7 590WThe LONGi Hi-MO 7 590W delivers 590W versus 545W per panel — 45W more. For an 8 kW system, you need 14 panels with the higher-wattage option versus 15 panels, saving 1 panels and the associated racking and labor costs.
5. Cell Technology
Winner: LONGi Hi-MO 7 590WThe LONGi Hi-MO 7 590W uses HPBC (Back Contact N-type): HPBC (Hybrid Passivated Back Contact) is a proprietary LONGi architecture combining back-contact design with advanced passivation for both high efficiency and aesthetic uniformity. The Waaree WS-545 Bifacial uses TOPCon N-type Bifacial: TOPCon (Tunnel Oxide Passivated Contact) adds a thin tunnel oxide layer to reduce recombination losses, achieving higher efficiency than PERC while being manufacturable on existing production lines. HPBC (Back Contact N-type) represents a newer generation technology with a longer performance runway as manufacturing matures.
LONGi Hi-MO 7 590W
The Hi-MO 7 is LONGi's flagship residential panel using proprietary HPBC (Hybrid Passivated Back Contact) cell technology for exceptional 22.8% efficiency and 590W output.
Pros
- + Industry-leading HPBC back-contact technology
- + 22.8% efficiency
- + Excellent temperature coefficient
- + Lower degradation rate
Cons
- - Premium pricing
- - Heavy at 28.8 kg
- - New technology with limited track record
Waaree WS-545 Bifacial
The Waaree WS-545 Bifacial is a 545W TOPCon N-type bifacial panel from India's largest solar module manufacturer. Waaree Energies has rapidly scaled to become a top-10 global solar manufacturer, and the WS-545 represents their flagship utility and commercial product. The bifacial design captures reflected light from the rear side for 5-25% additional energy gain depending on ground albedo. The N-type TOPCon cells deliver -0.30%/°C temperature coefficient and lower degradation than PERC. Waaree's Indian manufacturing provides an alternative supply chain to Chinese panels, particularly relevant for markets implementing anti-dumping duties.
Pros
- + Indian manufacturing — alternative to Chinese supply chain
- + Bifacial design adds 5-25% energy gain from rear side
- + TOPCon N-type with -0.30%/°C temp coefficient
- + Competitive pricing — among the most affordable TOPCon bifacial panels
- + 30-year performance warranty with low 0.4% annual degradation
- + Waaree is India's largest module manufacturer with 12+ GW capacity
Cons
- - Limited US brand recognition and distribution
- - 12-year product warranty shorter than premium brands' 25 years
- - 545W is mid-range — Chinese competitors offer 580W+ in same size
- - Bifacial gain requires appropriate mounting (ground or elevated rack)
Choose LONGi Hi-MO 7 590W 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
- ✓ You live in a hot climate (Arizona, Texas, Florida) where heat performance matters
- ✓ Premium residential installations seeking maximum efficiency.
Choose Waaree WS-545 Bifacial If...
- ✓ You prefer newer cell technology with a longer performance improvement runway
- ✓ Commercial and utility-scale projects seeking cost-effective TOPCon bifacial panels from a non-Chinese supply chain, and ground-mount residential systems where bifacial gain is maximized.
Our Recommendation
We recommend the LONGi Hi-MO 7 590W for most buyers in this comparison. It wins 4 of 5 key dimensions and offers a clear advantage in the metrics that matter most for a solar panel purchase. The Waaree WS-545 Bifacial remains a good product, but the LONGi Hi-MO 7 590W delivers better overall value for the majority of installations.
Frequently Asked Questions
Which is better, LONGi Hi-MO 7 590W or Waaree WS-545 Bifacial?
The LONGi Hi-MO 7 590W wins this comparison by a clear margin. It leads in efficiency (22.8% vs 21.2%) and matches or exceeds on warranty (12 vs 12 years). For most residential installations, the LONGi Hi-MO 7 590W is the stronger choice.
Which panel is more efficient, LONGi Hi-MO 7 590W or Waaree WS-545 Bifacial?
The LONGi Hi-MO 7 590W at 22.8% module efficiency. Higher efficiency means more watts per square foot of roof space, which is critical for space-constrained installations. The difference of 1.6 percentage points translates to approximately 45W per panel under standard test conditions.
Which has a better warranty, LONGi Hi-MO 7 590W or Waaree WS-545 Bifacial?
The LONGi Hi-MO 7 590W comes with a 12-year product warranty and 30-year performance guarantee. The Waaree WS-545 Bifacial offers 12-year product and 30-year performance warranties. Both offer identical warranty terms.
Which panel performs better in hot weather?
The LONGi Hi-MO 7 590W has a temperature coefficient of -0.28%/°C and the Waaree WS-545 Bifacial is -0.3%/°C. LONGi Hi-MO 7 590W retains more power in heat — important in states like Arizona, Texas, and Florida. A lower (less negative) temperature coefficient is better.
How many LONGi Hi-MO 7 590W vs Waaree WS-545 Bifacial panels do I need for an 8 kW system?
For an 8 kW system: you need 14 LONGi Hi-MO 7 590W panels (590W each) or 15 Waaree WS-545 Bifacial panels (545W each). The LONGi Hi-MO 7 590W requires fewer panels, saving on racking hardware and installation labor.
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Last updated: February 2026