Small-scale and three-phase solar energy systems don’t necessarily go hand in hand. When three-phase energy supply exists in a residential scenario, solar and battery options tend to become quite limited. With such limitations at play, is the Fronius Symo inverter range going to be a suitable solution for your three-phase power supply requirements? 

.Make and model:  Fronius Symo.

Variants: 3.0 | 4.0 | 5.0 | 6.0 | 7.0 | 8.2 kW.


  Noise emission.

Fronius inverters, in general, have a good reputation, but this doesn’t automatically define the Fronius Symo as the best solar inverter for your three-phase power supply.

Assessing the essential criteria of Design, Features, Performance, Guarantee and Software, explore the Fronius Symo inverter against the industries best-known specifications. With the critical information at hand, gauge whether the Fronius Symo is the right fit for what you expect from a three-phase solar inverter technology.

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The Fronius Symo overall design is very similar to that of its single-phase counterpart, the Fronius Primo. A highly efficient transformerless design built to accommodate a wide variety of solar array formations. Supported by an IP65 weather rating, the Fronius Symo can be mounted both indoors and out, ideally with protection from direct sunlight.

With no change for over 5-years the controlled air cooling by an internal fan provides excessive noise as opposed to convection cooling. Battery compatibility can be distributed across three-phases through a DC coupled solar battery such as the SolarWatt matrix. A solution which does not provide an emergency power supply function in the event of a grid failure. Alternatively, AC coupled battery compatibility is the only solution.

Download the Fronius Symo datasheet here:
Fronius Solar Inverter - Solar Review


Symo Design; VERY GOOD
  • AC Coupled battery compatibility.
  • No change for the last 5-years.
  • Fan Cooled.
  • Major internationally recognised award.
  • TÜV Reihnland certified.
  • Standard
  • IP 65.


The Fronius Symo excels within the features department. An inbuilt DC isolator reduces the need for additional isolation points. WiFi or Ethernet communication capabilities facilitate access to the feature-rich Fronius Solar.web monitoring portal. Additionally, an advanced shadow management protocol in the form of Dynamic Peak Manager heightens the production of the dual MPPT DC input.

Lacking a Fronius supplied module-level optimisation option, such can be achieved through the Tigo range if requirements exist. Although, Fronius do have module-level rapid shutdown add-ons available if required (as in the US). For advanced consumption monitoring insight, the Fronius Smart Meter is an essential feature add-on.

Fronius Symo Solar Inverter Display - Solar Review


Symo Features; SUPERIOR
  • 2 MPPT.
  • LCD graphic interface.
  • WiFi & Ethernet inbuilt.
  • No manufacturer supplied module-level optimisation options.
  • Manufacturer supplied module-level rapid shutdown options.
  • Manufacturer supplied expanded monitoring options.
  • Nominated shadow management protocol onboard.
  • Remote access firmware updates.


An admirable performer, the Fronius Symo has an above-average European weighted efficiency of up to 97.5% which derates beyond 40oC (140oF). With such, Fronius Symo’s can endure environmental conditions ranging between -25oC to +60oC (-13oF to +140oF) with a 100% permitted humidity.

Weight ranges from 19.9kG (43.8 lbs) to 21.9kG (46.3 lbs) in larger models. While caution should be exercised in noise-sensitive mounting locations as noise emission criteria rank as “not listed” earning the lowest possible mark in this area. Possibly a gauge, the Fronius Primo max noise emission level is 65 dB(A).


Symo Performance; SUPERIOR
  • 97.5% European weighted efficiency.
  • Min temp range -40°C (-40°F).
  • Max temp range +60°C (140°F).
  • Temp derating 40°C (104°F).
  • Weight 19.9 kg (43.8lbs).
  • Noise emission (not listed) dB (A).


A 10-year warranty activated upon installation via a Fronius trained installer network ensures an OUTSTANDING warranty for the end-user. For non-Fronius partners, the base Fronius Symo inverter guarantee is an industry average 5-year parts and labour warranty with expandable warranty options available for purchase through Fronius. However, cost and availability vary depending on the country of which the installation occurs.

Fronius Symo - Solar Review


Symo Guarantee; OUTSTANDING
  • 10-year parts warranty.*
  • 10-year service warranty.*
  • *Authorised installer network with additional end-user benefits.


A cut above most other manufacturer supplied monitoring options. See the full Fronius Solar.web monitoring software review for more insight > (Coming Soon).


Symo Software; SUPERIOR
  • Fronius Solar.web
  • iOS & Android app.
  • Alerts & fault diagnosis.


An inspiring three-phase residential solar inverter of the previous decade, the Fronius Symo has won consistent favour among both industry professionals and end-users. As we now progress into the new decade, a refreshed design remains eagerly anticipated.

However, with such a well built three-phase solar inverter, Fronius can continue to leverage off the success a little longer with limited competition in the small-scale three-phase division. The Fronius Symo is a SUPERIOR three-phase inverter which has proven the test of time.


Symo Overall; SUPERIOR
  • Design 3.7
  • Features 4.1
  • Performance 3.9
  • Guarantee 5.0
  • Software 4.0
[ 4.8 - 5 ] The pinnacle of certified specification.
[ 4.3 - 4.7 ] A rare calibre of technology produced by the industry elite.
[ 3.8 - 4.2 ] Specifications which are exceedingly superior to that of the industry average.
Very Good
[ 3.3 - 3.7 ] Advanced technology against the industry average.
[ 2.8 - 3.2 ] Better than the industry average is that of which strives a portion better.
[ 2.3 - 2.7 ] A score within this bracket is considered the industry average specification.
[ 1.8 - 2.2 ] Considered below the industry mainstream average.
[ 1.3 - 1.7 ] There's better, there's also worse.
[ 0.8 - 1.2 ] Far below the modern industry average.
[ 0.3 - 0.7 ] Possesses specifications which are absent or unverified by a certified testing institute.
[ 0 - 0.2 ] Unlikely for technology manufactured in the modern era.


How was the score for the Fronius Symo calculated? By utilising the Solar Review Inverter Assessment Criteria V2.3 >


  1. I am using the Fronius Symo inverter for my 10 kw solar on grid system. I am getting only 80% efficiency. Can you please send someone to inspect the installation? Pradeep Vishnupriya.

    • Hey Pradeep, thanks for reaching out! Great to hear from friends all over this sunny planet. Getting to India is a bit of a stretch for our techies but let’s see if we can support you remotely as we are well versed with the Fronius Symo. Plus it costs nothing to ask! Let’s establish first what exactly you have. When you say running at 80% efficiency do you mean you have 10kW of solar panels on a 10kW Fronius Symo inverter only producing a total of 8kW on average?

  2. I got the fronious symo with 6kw solar system in October last year. However after few days from installation I kept getting emails from the solar web advising there is an error: AC voltage too high. Worried that this will have bad effect on my converter. Also the inverter stopped for one day last month then began to work. Can you please advise

    • The inverter is basically operating within the settings it has been programmed to in order to meet the parameters required by your local grid. This will not harm the inverter, truth be told it can actually be programmed to accommodate higher grid voltage requirements (that’s one solution). In the event of a high AC voltage, it is normal for the inverter to stop until operational parameters are met again. The issue in such case should be addressed with the local supply authority to address increased grid voltages. Goodluck!


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