# KOSTAL InverterApp vs Fronius Solar.start

The clearest difference is review sentiment: KOSTAL InverterApp at 50% against Fronius Solar.start's 22%. KOSTAL InverterApp also leads on iOS requirement (13.0 vs 16.0). On price, update cadence, ads and in-app purchases there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Both ship on a similar rhythm, roughly every 2 months. The most recent releases landed on October 11, 2026 and October 24, 2026 respectively.

## The numbers

| Metric | KOSTAL InverterApp | Fronius Solar.start |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[3.0 (5 ratings)](https://appshunter.io/ios/app/fronius-solarstart/id1509399310/reviews)** |
| Number of ratings | — | **5** |
| Positive reviews | **50.0% of reviews** | 21.8% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 2 months | Every 2 months |
| Monetization | Free | Free |
| Size | 78 MB | 202 MB |
| Requires iOS | **13.0** | 16.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 17+ |
| Developer | [KOSTAL Industrie Elektrik GmbH](https://appshunter.io/developer/1436479665) | [Fronius International GmbH](https://appshunter.io/developer/431601279) |

## What reviewers say

### KOSTAL InverterApp

[App page](https://appshunter.io/ios/app/kostal-inverterapp/id1436479666)

Access and manage KOSTAL drive controllers with Bluetooth via your smartphone or tablet. Perform diagnostics, commissioning, and parameter settings remotely. Data records are compatible with PC software for seamless workflow.

**Highlights:** Bluetooth connectivity, Wizard-guided commissioning, Save and copy device settings, Send data records via email, Parameter settings in plain text, Control drive controller, Access process variables, Error analysis and history

**Features:** macOS Compatibility

**In-app purchases:** none


### Fronius Solar.start

[App page](https://appshunter.io/ios/app/fronius-solarstart/id1509399310)

This app simplifies the setup of Fronius inverters and related devices through a guided, step-by-step process. It allows for quick commissioning, firmware updates, and integration with the Fronius Solar.web monitoring platform directly from a mobile device.

**Highlights:** QR-code scanning for device setup, Step-by-step commissioning guide, Inverter firmware updates, Network and product configuration, Integration with Fronius Solar.web, Quick access to web interface, How-to videos

**In-app purchases:** none


## Frequently asked questions

### Is KOSTAL InverterApp free?

KOSTAL InverterApp is free to download, with no in-app purchases.

### Is Fronius Solar.start free?

Fronius Solar.start is free to download, with no in-app purchases.

### Do KOSTAL InverterApp or Fronius Solar.start have ads?

Neither KOSTAL InverterApp nor Fronius Solar.start shows ads.

### Which is updated more often, KOSTAL InverterApp or Fronius Solar.start?

KOSTAL InverterApp ships an update every 2 months, and Fronius Solar.start every 2 months. Most recently, KOSTAL InverterApp was updated on October 11, 2026 and Fronius Solar.start on October 24, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*