Fronius Inverter Review
Fronius Inverter Review

Fronius Inverter Review

Fronius inverters occupy the premium shelf regarding product quality, customer support, and price. While other brands are better than Fronius in some respects, it’s hard to find a safer and more popular choice. The extensive support of installers and the established brand ensure that the equipment will work well — and if it doesn’t, it will be repaired quickly.

What is Fronius?

Fronius is an Austrian company founded in 1945 by Mr. Günter Fronius. They have been producing inverters since 1992. They have been competing with SMA for prestige in the industry for many years, and it can be said that they have been going head-to-head for the last few years.


Reliability means resistance to both the passage of time and difficult operating conditions.

Factory warranty: If you buy in Australia and other English-speaking countries, you will receive a 5-year warranty. Unfortunately, in Europe, you only get an initial 2-year Fronius Plus warranty, which you can extend free of charge to 5 years under the same conditions (Fronius Plus Warranty) or up to 7 years under slightly worse conditions (Fronius Guarantee).

The Fronius Plus warranty means that in the event of a fault, Fronius provides you with spare parts or a replacement device and covers the service costs (assembly, disassembly, labor). On the other hand, the Fronius warranty does not cover any services and must be paid for by the user. None of these guarantees cover shipping costs. These guarantees are, honestly, not the best.

Extended warranty: Fronius offers paid warranty extensions of up to 10, 15, or 20 years as part of the two packages mentioned above.

The fact that the inverter warranty can be extended up to 20 years shows that Fronius believes in the high quality of the devices it produces. This also shows that Fronius inverters are not worth replacing but simply repairing.

The active cooling system performs well at high temperatures, but the rotor may fail after several years. If I had to bet, this is the most likely wear part. However, the rest of the inverter should work well for years, so replacing the fan is a good solution.

Reliability acc. PVEL: Fronius won the TOP PERFORMER award in the PVEL 2019 reliability tests for its inverter immunity in the grounding and arc fault tests. This means that their inverters perfectly identify and respond to grounding problems. For example, they can distinguish between the positive pole and ground from an arc between the 3rd and 4th module in the string, react quickly, and correctly describe the problem.

IP degree of protection: all Fronius inverters have IP65 protection, and some even IP66. In short, this means that they are not afraid of storms, and to flood them with water, you would have to throw them into the river.

To sum up, there is a good chance that Fronius inverters will work for up to 20 years, provided they are properly serviced. To obtain them, it is best to purchase an appropriate warranty package.


Inverters’ efficiency is converting direct current produced by the panels into alternating current that powers the equipment in our home/plant. The yield also significantly impacts how often the inverter hangs, turns off, shows errors, etc. Nothing works when the inverter doesn’t work, so even short downtimes are expensive.

Reliable performance acc. PVEL: Fronius won the TOP PERFORMER award in the PVEL 2019 reliability tests for their inverter’s performance in the high-temperature performance test and the full-range performance test examining the transient response. This inverter gives excellent high-temperature results and copes perfectly with anomalies, reacting quickly to changes.

Temperature resistance: Inverters of this brand work efficiently in an extensive temperature range.

Optimization: Fronius inverters are compatible with TIGO, so it is possible to optimize the modules selectively — you do not have to install the optimizers on all modules, just those with a problem with shadow.


A reliable manufacturer will honor its warranty obligations if its products stop working for any reason. Fronius guarantees the operation of its products for 2 to 20 years. We need to ensure that the company will survive this period and be willing to fulfill its warranty obligations.

Company size: Fronius is one of the largest manufacturers of solar inverters in the world. Additionally, the financial stability of a company is not based only on one industry. Fronius also produces welding equipment and battery chargers.

Fronius is a large, stable, reliable company that should survive for 20 years.


Fronius inverters are expensive but still cheaper than systems with optimizers or microinverters.

High price for high quality. Investing in a better inverter is worth it because each inverter failure interrupts the entire installation’s operation.


A photovoltaic installation may pose a fire hazard in two ways: it may cause ignition, and if the cause of ignition is something else, it may intensify the fire and make firefighting more difficult.

How Fronius protects your installation from ignition — Fronius inverters have an earth fault detection function, an insulation state monitoring function, and a DC disconnector.

How Fronius protects against the spread of fire and facilitates firefighting — To obtain such protection, it is necessary to purchase additional devices. Fronius works with TIGO optimizers, so installing TIGO modules with the Rapid Shutdown function is the safest solution.

Fronius inverter — individual series

Let’s look at this brand’s most critical inverter series.

1. Fronius Symo

Perfect your phase inverter. It is available in power versions from 3 to 20 kW. Using Wi-Fi or Ethernet, it communicates with the Solarweb website, enabling remote monitoring of the installation’s operation. You can also download the latest software using this platform.

IP66 protects against water, dust, etc. (IP65 in some versions). It can operate in the temperature range from -40 to +60°C (some versions from -25°C). The only apparent drawback is the noise emitted by the fan cooling system. Install outdoors or in the basement/boiler room!

It is a good option if you need your phase inverter with low power. In 2019, the reliability of the Symo series inverter was the subject of research by the PVEL Institute. It won distinctions in 3 categories:

1. Performance test against complete temperature cycles: Top Performer
2. Performance test over the full range of operating characteristics — transient response: Top Performer
3. Ground and Arc Fault Field Test: Top Performer

These distinctions mean that Fronius Symo can perfectly adapt to rapidly changing conditions. Maintains high efficiency despite temperature changes and changes in operating characteristics. It is also excellent at detecting grounding problems and short circuits, which can protect the installation against fire.

2. Fronius Primo

A suitable single-phase inverter. Armored and fan-cooled, i.e., efficient and reliable, but also large, heavy, and noisy. It allows you to monitor the operation of the installation via the solar.web website; It can operate at very high and very low temperatures. Fronius Primo received the +x Product of the Year (Plus X Award) in 2019. This is proof that this design is constantly being improved.

3. Fronius Galvo

Small inverters with power from 1.5 to 3.1 kW. It’s a transformer inverter. This is a slightly old design, and its efficiency is lower than newer transformerless ones. However, such inverters are required for some photovoltaic modules. They also provide galvanic isolation between the DC and AC sides.

4. Fronius Primo / Symo Hybrid

A hybrid inverter, i.e., capable of operating an energy storage facility and working in a situation where the power grid has failed. Primo Hybrid inverters are single-phase, and Symo Hybrid are three-phase.

5. Fronius Primo / Symo GEN24

A unique hybrid inverter. Like the Hybrid series, it can provide complete backup power using the energy stored in the battery. However, it offers limited backup power without energy storage thanks to the PV Point function. Primo GEN24 inverters are single-phase, and Symo GEN24 — three-phase.

The Fronius GEN24 has one built-in socket, which is normally de-energized. However, if the network goes down, it will be restarted after 30 seconds without energy storage! You can connect your most crucial devices to it, such as chargers or a refrigerator.

This circuit operates at low power and only when the sun shines, but it’s better than no electricity! You can purchase a DC energy storage unit anytime for an emergency power supply.

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