# Viessmann Access vs Gastite Sizing App

The clearest difference is update cadence: Gastite Sizing App at every 3 weeks against Viessmann Access's every 4 months. On price, ads, in-app purchases and device support there is nothing between them.

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

Viessmann Access ships an update every 4 months, Gastite Sizing App every 3 weeks. The most recent releases landed on August 12, 2026 and June 5, 2026 respectively.

## The numbers

| Metric | Viessmann Access | Gastite Sizing App |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 4 months | **Every 3 weeks** |
| Monetization | — | Free |
| Size | 52 MB | 15 MB |
| Requires iOS | **12** | 13.0 |
| Devices | iPhone, iPod | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Viessmann IT Service GmbH](https://appshunter.io/developer/1801739683) | [Gastite Systems Limited](https://appshunter.io/developer/1537998855) |

## What reviewers say

### Viessmann Access

[App page](https://appshunter.io/ios/app/viessmann-access/id1533222623)

**In-app purchases:** none


### Gastite Sizing App

[App page](https://appshunter.io/ios/app/gastite-sizing-app/id1537998852)

This app simplifies calculating the required size of Gastite® CSST for gas installations. Input gas type, CSST length, and appliance power to instantly determine the correct size. It offers easy navigation, user-friendly design, and access to FAQs and installation guides.

**Highlights:** CSST sizing calculation, Natural gas or LPG selection, Access to FAQs, Downloadable installation guide, User-friendly design, Contact support

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Viessmann Access free?

Viessmann Access is free to download, with no in-app purchases.

### Is Gastite Sizing App free?

Gastite Sizing App is free to download, with no in-app purchases.

### Do Viessmann Access or Gastite Sizing App have ads?

Neither Viessmann Access nor Gastite Sizing App shows ads.

### Which is updated more often, Viessmann Access or Gastite Sizing App?

Viessmann Access ships an update every 4 months, and Gastite Sizing App every 3 weeks. Most recently, Viessmann Access was updated on August 12, 2026 and Gastite Sizing App on June 5, 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.*