# Lüftungstool vs HydroCalc

The clearest difference is price: HydroCalc at Free against Lüftungstool's $2.99. Lüftungstool's advantage is in-app purchases (none vs 1) and iOS requirement (15.2 vs 17.0). On update cadence, ads and device support there is nothing between them.

HydroCalc is free to download; Lüftungstool costs $2.99 up front. HydroCalc sells 1 one-off in-app purchase. Lüftungstool asks for nothing beyond the download.

Lüftungstool ships an update every 3 weeks, HydroCalc every 5 weeks. The most recent releases landed on October 25, 2026 and October 31, 2026 respectively.

## The numbers

| Metric | Lüftungstool | HydroCalc |
| --- | --- | --- |
| Price | $2.99 | **Free** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Every 3 weeks** | Every 5 weeks |
| Size | 6 MB | 2 MB |
| Requires iOS | **15.2** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Burak Doelek](https://appshunter.io/developer/1602361104) | [Piotr Kaminski](https://appshunter.io/developer/6799375980) |

## What reviewers say

### Lüftungstool

[App page](https://appshunter.io/ios/app/luftungstool/id1603666086)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### HydroCalc

[App page](https://appshunter.io/ios/app/hydrocalc-heating-and-flow/id6801788464)

**Features:** macOS Compatibility, Vision Pro support, iPhone Duo support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| HydroCalc Pro | $3.99 | one-time |


## Frequently asked questions

### Is Lüftungstool free?

Lüftungstool costs $2.99, with no in-app purchases.

### Is HydroCalc free?

HydroCalc is free to download, with in-app purchases available.

### Do Lüftungstool or HydroCalc have ads?

Neither Lüftungstool nor HydroCalc shows ads.

### Which is updated more often, Lüftungstool or HydroCalc?

Lüftungstool ships an update every 3 weeks, and HydroCalc every 5 weeks. Most recently, Lüftungstool was updated on October 25, 2026 and HydroCalc on October 31, 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.*