# Digiduct vs Duct Sizer Calc HVAC

The clearest difference is price: Digiduct at Free against Duct Sizer Calc HVAC's $0.99. Digiduct also leads on in-app purchases (none vs 1). Duct Sizer Calc HVAC's advantage is update cadence (every 3 weeks vs every 2 months) and iOS requirement (13.0 vs 26.2). On ads and device support there is nothing between them.

Digiduct is free to download; Duct Sizer Calc HVAC costs $0.99 up front. Duct Sizer Calc HVAC sells 1 one-off in-app purchase. Digiduct asks for nothing beyond the download.

Digiduct ships an update every 2 months, Duct Sizer Calc HVAC every 3 weeks. The most recent releases landed on October 1, 2026 and September 23, 2026 respectively.

## The numbers

| Metric | Digiduct | Duct Sizer Calc HVAC |
| --- | --- | --- |
| Price | **Free** | $0.99 |
| Rating | **[4.6 (11 ratings)](https://appshunter.io/ios/app/digiduct/id6738926359/reviews)** | — |
| Number of ratings | **11** | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 2 months | **Every 3 weeks** |
| Monetization | Ad-supported | — |
| Size | 4 MB | 34 MB |
| Requires iOS | 26.2 | **13.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 17+ |
| Developer | [Syska Hennessy Group](https://appshunter.io/developer/1782943081) | [Rizvan Adzhoian](https://appshunter.io/developer/1891746079) |

## What reviewers say

### Digiduct

[App page](https://appshunter.io/ios/app/digiduct/id6738926359)

This HVAC tool assists professionals with duct sizing calculations based on ASHRAE standards. It supports multiple duct shapes and offers intelligent features to ensure accurate and reliable designs for real-world scenarios.

**Highlights:** Duct sizing for rectangular, round, and flat oval ducts, Customizable dimensions with locked values, Duct location intelligence for context-aware sizing, Calculations based on CFM, pressure drop, or velocity, Alerts for exceeding pressure drop or velocity limits

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

**In-app purchases:** none


### Duct Sizer Calc HVAC

[App page](https://appshunter.io/ios/app/duct-sizer-calc-hvac/id6764646921)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Pro Unlock | $2.99 | one-time |


## Frequently asked questions

### Is Digiduct free?

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

### Is Duct Sizer Calc HVAC free?

Duct Sizer Calc HVAC costs $0.99, and also offers in-app purchases.

### Do Digiduct or Duct Sizer Calc HVAC have ads?

Neither Digiduct nor Duct Sizer Calc HVAC shows ads.

### Which is updated more often, Digiduct or Duct Sizer Calc HVAC?

Digiduct ships an update every 2 months, and Duct Sizer Calc HVAC every 3 weeks. Most recently, Digiduct was updated on October 1, 2026 and Duct Sizer Calc HVAC on September 23, 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.*