# ISO vs Duct Construction

The clearest difference is chart position: Duct Construction at #67 against ISO's unranked. ISO's advantage is iOS requirement (15.6 vs 17.6). On price, update cadence, ads and in-app purchases there is nothing between them.

ISO costs $0.99 and Duct Construction $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ISO ships an update every 18 months, Duct Construction every 10 months. The most recent releases landed on July 4, 2026 and September 25, 2026 respectively.

## The numbers

| Metric | ISO | Duct Construction |
| --- | --- | --- |
| Price | $0.99 | $0.99 |
| Rating | — | **[1.0 (1 ratings)](https://appshunter.io/ios/app/duct-construction/id6443518338/reviews)** |
| Number of ratings | — | **1** |
| Positive reviews | — | 0.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 18 months | **Every 10 months** |
| Monetization | — | Paid |
| Best chart rank | — | **#67** |
| Size | 1 MB | 1 MB |
| Requires iOS | **15.6** | 17.6 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 17+ | 4+ |
| Developer | [Bjarne Berge](https://appshunter.io/developer/1209858941) | [Wassim Murr](https://appshunter.io/developer/1474939474) |

## What reviewers say

### ISO

[App page](https://appshunter.io/ios/app/iso-5167/id1356345079)

**Features:** macOS Compatibility

**In-app purchases:** none


### Duct Construction

[App page](https://appshunter.io/ios/app/duct-construction/id6443518338)

**Currently charting:** #67 Top Paid · Productivity (US App Store)

This app helps determine duct construction and reinforcement options based on duct size and system pressure class. It provides condensed lists of suitable options, saving time spent on manual calculations and table lookups. Results are based on industry standards for galvanized steel duct sheets.

**Highlights:** Duct size range from 2" to 120", Pressure classes up to 4 in.wg, Calculates duct weights per linear foot, Determines required duct gauge and reinforcement spacing, Clear illustrations for reinforcement types, Simple and effective UI design

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

**In-app purchases:** none


## Frequently asked questions

### Is ISO free?

ISO costs $0.99, with no in-app purchases.

### Is Duct Construction free?

Duct Construction costs $0.99, with no in-app purchases.

### Do ISO or Duct Construction have ads?

Neither ISO nor Duct Construction shows ads.

### Which is updated more often, ISO or Duct Construction?

ISO ships an update every 18 months, and Duct Construction every 10 months. Most recently, ISO was updated on July 4, 2026 and Duct Construction on September 25, 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.*