Fronius Primo 5.0-1 vs Sungrow SG10RT
The Sungrow SG10RT edges ahead in this string-vs-string matchup. It delivers higher efficiency (97.5% vs 96.5% CEC). For most installations in this power range, the Sungrow SG10RT is the stronger choice.
Key Differences
- • Fronius Primo 5.0-1 delivers 5.0 kW AC output while Sungrow SG10RT delivers 10.0 kW, a 5000W difference.
- • Sungrow SG10RT achieves 97.5% CEC efficiency vs 96.5%.
- • Both carry 10-year warranties.
Specifications Breakdown
Power Output & Efficiency
The Fronius Primo 5.0-1 delivers 5.0 kW AC output at 96.5% CEC efficiency (97% peak), while the Sungrow SG10RT delivers 10.0 kW at 97.5% CEC (98.5% peak). The 5000W power difference is substantial and determines the maximum solar array each inverter can handle. The Sungrow SG10RT's higher CEC efficiency means it converts 1.0 percentage points more DC solar energy into usable AC electricity. On an average 8 kW system producing 12,000 kWh annually, this efficiency gap translates to approximately 120 kWh more usable energy per year, worth roughly $18 at $0.15/kWh.
MPPT Trackers & Panel Configuration
The Fronius Primo 5.0-1 features 2 MPPT inputs while the Sungrow SG10RT has 2. Matched MPPT counts provide equal flexibility for panel string configuration. Both can independently optimize 2 separate panel groups. The Fronius Primo 5.0-1 accepts up to 600V DC input with a 80-600V operating range, versus 1000V DC and 160-1000V for the Sungrow SG10RT.
Monitoring & Communication
The Fronius Primo 5.0-1 includes Fronius Solar.web (WiFi/Ethernet) monitoring with WiFi / Ethernet / USB / Fronius Solar API communication, while the Sungrow SG10RT offers iSolarCloud App (WiFi/Ethernet) via WiFi, RS485, Ethernet. Different monitoring ecosystems mean different mobile app experiences, data granularity, and integration options with third-party energy management systems. Reliable monitoring is essential for detecting production drops, identifying panel-level issues, and maximizing system uptime over the inverter's lifetime. Both carry IP65 protection ratings for equivalent environmental durability.
Warranty & Reliability
The Fronius Primo 5.0-1 comes with a 10-year warranty while the Sungrow SG10RT offers 10 years. Matched warranty durations mean equal long-term manufacturer protection. Consider budgeting for a potential inverter replacement during the 25-30 year lifespan of your solar panels.
Specification Comparison
| Specification | Fronius Primo 5.0-1 | Sungrow SG10RT |
|---|---|---|
| Type | string | string |
| AC Power | 5000W | 10000W |
| Peak Efficiency | 97% | 98.5% |
| CEC Efficiency | 96.5% | 97.5% |
| MPPT Trackers | 2 | 2 |
| Monitoring | Fronius Solar.web (WiFi/Ethernet) | iSolarCloud App (WiFi/Ethernet) |
| Weight | 21.5 kg | 18 kg |
| Warranty | 10 years | 10 years |
5-Dimension Head-to-Head Analysis
1. Power Capacity
Winner: Sungrow SG10RTThe Sungrow SG10RT delivers 10.0 kW versus 5.0 kW. This is a significant capacity difference that determines the maximum solar array size each can support.
2. Conversion Efficiency
Winner: Sungrow SG10RTThe Sungrow SG10RT achieves 97.5% CEC efficiency versus 96.5%. Every percentage point of efficiency translates to approximately $100-200 in additional energy production over a 25-year system life on an average 8 kW system. The difference is noticeable but not dramatic in total lifetime energy value.
3. Features & Architecture
Winner: TieBoth are strings with 2 MPPT trackers. Matched MPPT counts mean equal roof configuration flexibility.
4. Warranty & Reliability
Winner: TieBoth carry 10-year warranties — equal long-term protection.
5. Overall Value
Winner: Sungrow SG10RTWeighing efficiency, warranty, and power capacity together, the Sungrow SG10RT delivers the better overall package. Get installer quotes for both to compare actual installed costs in your area.
Fronius Primo 5.0-1
The Fronius Primo 5.0-1 is a 5 kW single-phase SnapINverter with dual MPPT and SuperFlex design, one of the most widely installed residential string inverters in the US market from 2015-2022.
Pros
- + Proven reliability with millions of units deployed globally
- + Dual MPPT with wide 80-600V range for maximum design flexibility
- + Fronius Solar.web provides excellent free monitoring with open API
- + SnapINverter quick-disconnect simplifies service and replacement
- + IP65 and -40°C rating for all US climates
Cons
- - No battery or hybrid capability
- - 96.5% CEC efficiency trails newer inverter platforms
- - Discontinued — succeeded by Primo GEN24 5.0 Plus
- - 10-year warranty without extension options on discontinued models
Sungrow SG10RT
The Sungrow SG10RT is a 10kW three-phase string inverter featuring dual MPPT trackers and 98.5% peak efficiency. As part of Sungrow's RT series for residential applications, it combines a compact form factor with high performance. The lightweight 18kg design is among the lightest in its class.
Pros
- + Ultra-light 18kg design — lightest in the 10kW three-phase class
- + 98.5% peak efficiency for maximum energy harvest
- + Built-in WiFi and Ethernet for flexible monitoring connectivity
- + IP65 rated for outdoor installation
Cons
- - Three-phase only — not suitable for US split-phase residential
- - No battery integration capability
- - 10-year standard warranty — extensions available at cost
Choose Fronius Primo 5.0-1 If...
- ✓ Standard 4-6 kW residential systems prioritizing Fronius reliability and dual MPPT flexibility.
Choose Sungrow SG10RT If...
- ✓ You want maximum energy conversion efficiency to minimize power losses
- ✓ Your system size requires 10 kW+ of inverter capacity
- ✓ International residential or small commercial three-phase installations seeking lightweight, efficient conversion
Our Recommendation
The Sungrow SG10RT is the decisive winner in this inverter comparison, outperforming the Fronius Primo 5.0-1 in 3 of 5 dimensions. Unless you have a specific requirement that the Fronius Primo 5.0-1 uniquely addresses, the Sungrow SG10RT is the stronger choice for virtually every installation scenario.
Frequently Asked Questions
Which is better, Fronius Primo 5.0-1 or Sungrow SG10RT?
The Sungrow SG10RT edges ahead in this string-vs-string matchup. It delivers higher efficiency (97.5% vs 96.5% CEC). For most installations in this power range, the Sungrow SG10RT is the stronger choice.
Which inverter is more efficient?
The Fronius Primo 5.0-1 achieves 96.5% CEC efficiency (97% peak) versus the Sungrow SG10RT at 97.5% CEC (98.5% peak). Sungrow SG10RT converts more DC solar power to usable AC electricity. CEC efficiency is the more realistic measure, accounting for varying power levels throughout the day.
Can Fronius Primo 5.0-1 or Sungrow SG10RT work with battery storage?
The Fronius Primo 5.0-1 is a string without built-in battery management. The Sungrow SG10RT is a string without built-in battery management. Both require an AC-coupled battery system (like Tesla Powerwall) for storage, or replacement with a hybrid inverter.
Which has a better warranty?
The Fronius Primo 5.0-1 offers 10 years versus 10 years for the Sungrow SG10RT. Both offer identical warranty terms. Paid warranty extensions are typically available from both manufacturers.
Which inverter type is better: string or string?
Both are strings, so the comparison comes down to specifications, brand ecosystem, and pricing rather than architecture. Compare efficiency, warranty, monitoring quality, and installer support when choosing between these two strings.
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Last updated: February 2026