Boasting many admirers due to good track record in the field, this doesn’t mean the Fronius Primo is the right inverter for you. Fact is, there are specific characteristics which would make the ageing Fronius Primo a very poor single-phase inverter solution. Make an informed decision as to whether the Fronius Primo is the right solar inverter for you.

.Make and model:  Fronius Primo.

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

Reliability, Fronius Solar.Web.

Noise, Outdated Design.

Why the admirers? In a nutshell, quality hardware built by a company with a decent track-record in manufacturing DC appliances for over 80-years. Proving a successful design, many of the key elements which make the Fronius Primo solar inverter are now almost a decade old. A nice sentiment to proven technology, however, a lot has changed over the last decade, and perhaps the Fronius Primo is now showing its age in more ways than one. 


As the end of a decade draws to a close, the once inspiring design of the Fronius Primo range has amassed many admirers from a successful inverter design. This design though is now old by today’s standard and a fraction of the innovation in which alternative single-phase transformerless inverters can offer in the same category.

Overall the size is larger than most. Double that of many others. Internal cooling is still regulated by a fan which noisy in operation and considered a likely point of failure. The Fronius Primo remains a worthier candidate than most for reliable outdoor installation even if the IP65 rating is less than alternatives. Battery compatibility is available only via an AC coupled, or a compatible DC coupled battery such as the SolarWatt Matrix.

Download the Fronius Primo datasheet here:

Fronius Symo Solar Inverter Logo - Solar Review


Primo - Design
  • AC and DC Coupled battery compatibility with selected battery
  • No change for the last 5-years.
  • Fan Cooled.
  • Major internationally recognised award.
  • TÜV Reihnland certified.
  • Standard
  • IP 65.


Features for greater installation flexibility include; WiFi and Ethernet communication, inbuilt DC isolator, Fronius supplied rapid shut down capabilities with the Fronius Rapid Shutdown Box (if required) and in-depth monitoring insight with additional Fronius devices such as the Fronius Smart Meter. Shadow management is enhanced by more than just dual MPPT array inputs with Fronius’s Dynamic Peak Manager onboard. Additional product support is available from installers to end-users with remote firmware updates possible, plus advanced monitoring data access.

A less than desirable feature in a modern sense is the LCD and basic LED interface. With the technology evolution of inverter information access from almost anywhere, a multifunction LED interface is the new standard to interpret basic operation locally. Local App without internet connection is a bonus if available from manufacturers. LCD graphic interfaces are a common point of failure in any inverter design and often expensive to repair. Finally, for those seeking module-level monitoring or optimisation capabilities, the Fronius Primo range has no manufacturer supplied option. To support such a feature a 3rd party device is required. 

Fronius Primo Inverter


Primo - Features.
  • 2+ MPPTS.
  • 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.
  • Installer remote access support is rated at - firmware updates.


Fronius Primo inverters are built to perform better in colder climates. The operating temperature range is outstanding for below-freezing conditions up to -40°C. For areas subject to constant heat the Fronius Primo’s upward temperature range is less than ideal, limited to only 55°C (131°F), derating after 40°C (104°F). Weight is a little on the excessive side by today’s standard. 21.5kg is almost 10kg heavier than alternative solar inverter offerings in the same class.

Perhaps the least desirable performance aspect for many given specific mounting locations is noise. The maximum noise emission from the Fronius Primo range is 65 dB(A).  Very noisy in comparison to alternatives at 25 dB(A) or less. Even though essential performance traits are outdated within this class of inverter, they are not entirely out of touch yet. European efficiency is of the higher order at 97% (avg).

Fronius Primo Inverter


Primo - Performance
  • 97% European efficiency.
  • Temperature range of -40°C (-40°F).
  • Temperature range of +60°C (140°F).
  • Temperature derating of 45°C (113°F).
  • Weighs 21.5 kg (47.3lbs).
  • Noise emission of 65 dB (A).


The base Fronius Primo inverter guarantee is a 5-year parts and labour warranty. Expandable warranty options are available for purchase through Fronius. However, cost and availability vary depending on the country of which the installation occurs. The most common warranty upgrade is the additional 5-year parts only warranty. Specific regions around the world such as Australia have enjoyed a complimentary offering of this upgrade (via redemption) for the last 2 to 3-years . 

Where warranty increases beyond base are available, a more end-user friendly approach is for the extension to be valid only through the use of a Fronius trained installation partner. Greater assurance that the product is installed to manufacturer specifications and the warranty has worth. Fronius, unfortunately, does not offer this.

Fronius Primo Inverter


Primo - Guarantee
  • 5-year parts warranty.
  • 5-year service warranty.
  • Authorised installer network with no 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).


Primo - Software
  • Fronius Solar.web
  • iOS & Android app.
  • Alerts & fault diagnosis.


For the technology inside, the Fronius Primo presents as a more expensive basic solar inverter option which does not necessarily mean it is better for any given task. Rather, the price is more of a reflection of the assembly location.

As a gauge, Fronius Primo 5.0-1 solar inverters are available online from: 

USD 1700  |  AUD 2400  |  EURO 1500 

Excludes taxes, shipping and installation.

Source – Google.

Fronius Primo Inverter


Primo - Affordability
  • Very good technology score.
  • 5kW approx for $1700 USD ex.


The Fronius Primo inverter is a proven single-phase solar inverter solution. The design hasn’t wavered much within the last decade, and as technology has evolved, the once high-spec Fronius Primo is now only somewhere near the top of its class with much of the competition learning from design flaws and evolving or better yet innovating. The question mark though, what will Fronius do next in the single-phase category? Solar inverters are the new brain of the modern energy smart home, and an innovative improvement here would be welcomed by many. 


Primo - Overall
  • Design 3.7
  • Features 4.1
  • Performance 3.7
  • Guarantee 2.8
  • Software 4.0
  • Technology 3.7
  • Affordability 4.1

Got questions? Or have an alternative perspective? Have your say in the comments.


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


  1. I got the fronius symo invertor with the 6kw solar system in October last year, however few days later, I kept getting emails from the solar web advising that there is an error: AC voltage too high
    Please advise


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