# GB Gas Ventilation Calculator vs SI Tech

The clearest difference is price: SI Tech at Free against GB Gas Ventilation Calculator's $3.99. SI Tech also leads on review sentiment (33% vs 0%) and update cadence (every 3 months vs every 14 months). On ads, in-app purchases and device support there is nothing between them.

SI Tech is free to download; GB Gas Ventilation Calculator costs $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.

GB Gas Ventilation Calculator ships an update every 14 months, SI Tech every 3 months. The most recent releases landed on November 6, 2026 and November 3, 2026 respectively.

## The numbers

| Metric | GB Gas Ventilation Calculator | SI Tech |
| --- | --- | --- |
| Price | $3.99 | **Free** |
| Rating | — | **[1.5 (8 ratings)](https://appshunter.io/ios/app/si-tech/id1510009992/reviews)** |
| Number of ratings | — | **8** |
| Positive reviews | 0.0% of reviews | **33.3% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 14 months | **Every 3 months** |
| Monetization | Paid | **Free** |
| Size | 3 MB | 23 MB |
| Requires iOS | 26.0 | **13.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [GB-GAS.CO.UK](https://appshunter.io/developer/425897007) | [CBRE, Inc.](https://appshunter.io/developer/359185439) |

## What reviewers say

### GB Gas Ventilation Calculator

[App page](https://appshunter.io/ios/app/gb-gas-ventilation-calculator/id426220160)

Calculate ventilation requirements for gas appliances, including open flued, room sealed, and flueless types. Determine free air area for existing and new vents to ensure suitability for appliances. Simplifies complex calculations by reading appliance data directly.

**Highlights:** Ventilation calculations for gas appliances, Supports open flued, room sealed, and flueless types, Calculates for multiple appliances in one room, Determines free air area of vents, Reads appliance data directly

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

**In-app purchases:** none


### SI Tech

[App page](https://appshunter.io/ios/app/si-tech/id1510009992)

This app helps facility maintenance and engineering teams manage service requests and work orders. It allows for searching supplier information, reviewing job plans, and completing workplace risk assessments to ensure safety and productivity.

**Highlights:** Manage service requests and work orders, Search supplier contact information, Review job plans, Complete workplace risk assessments, Update asset inspection tasks, Facilitate capital planning

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

**In-app purchases:** none


## Frequently asked questions

### Is GB Gas Ventilation Calculator free?

GB Gas Ventilation Calculator costs $3.99, with no in-app purchases.

### Is SI Tech free?

SI Tech is free to download, with no in-app purchases.

### Do GB Gas Ventilation Calculator or SI Tech have ads?

Neither GB Gas Ventilation Calculator nor SI Tech shows ads.

### Which is updated more often, GB Gas Ventilation Calculator or SI Tech?

GB Gas Ventilation Calculator ships an update every 14 months, and SI Tech every 3 months. Most recently, GB Gas Ventilation Calculator was updated on November 6, 2026 and SI Tech on November 3, 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.*