# HVAC Duct Sizer vs Digiduct

The clearest difference is price: Digiduct at Free against HVAC Duct Sizer's $4.99. Digiduct also leads on rating (4.6 vs 3.1) and in-app purchases (none vs 1). HVAC Duct Sizer's advantage is chart position (#191 vs unranked) and iOS requirement (17.0 vs 26.2). On ratings volume, ads and device support there is nothing between them.

Digiduct is free to download; HVAC Duct Sizer costs $4.99 up front. HVAC Duct Sizer sells 1 one-off in-app purchase. Digiduct asks for nothing beyond the download.

Digiduct holds the better App Store score, 4.6 against 3.1. Both are backed by a comparable volume of ratings — 9 and 11 respectively.

HVAC Duct Sizer ships an update every 6 months, Digiduct every 2 months. The most recent releases landed on September 17, 2026 and September 12, 2026 respectively.

## The numbers

| Metric | HVAC Duct Sizer | Digiduct |
| --- | --- | --- |
| Price | $4.99 | **Free** |
| Rating | [3.1 (9 ratings)](https://appshunter.io/ios/app/hvac-duct-sizer/id317970395/reviews) | **[4.6 (11 ratings)](https://appshunter.io/ios/app/digiduct/id6738926359/reviews)** |
| Number of ratings | 9 | **11** |
| Positive reviews | 64.1% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 6 months | **Every 2 months** |
| Monetization | Free with in-app purchases | **Ad-supported** |
| Best chart rank | **#191** | — |
| Size | 1 MB | 4 MB |
| Requires iOS | **17.0** | 26.2 |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Carmel Software Corporation](https://appshunter.io/developer/317970398) | [Syska Hennessy Group](https://appshunter.io/developer/1782943081) |

## What reviewers say

### HVAC Duct Sizer

[App page](https://appshunter.io/ios/app/hvac-duct-sizer/id317970395)

**Currently charting:** #191 Top Paid · Utilities (US App Store)

This app provides quick and simple HVAC duct sizing analysis. It allows users to calculate duct dimensions based on airflow or existing dimensions, and can also determine a range of duct sizes. Results can be emailed for further analysis.

**Highlights:** Duct sizing by airflow, Duct sizing by dimensions, Range of duct sizes calculation, Rectangular, round, and oval duct shapes, English and Metric unit options, Email results with CSV attachment, HVAC Equipment Locator

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| HVAC Equipment Locator | $9.99 | one-time |


### 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


## Frequently asked questions

### Is HVAC Duct Sizer free?

HVAC Duct Sizer costs $4.99, and also offers in-app purchases.

### Is Digiduct free?

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

### Which has better reviews, HVAC Duct Sizer or Digiduct?

Digiduct is rated higher. HVAC Duct Sizer averages 3.1 out of 5 from 9 ratings, while Digiduct averages 4.6 from 11 ratings.

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

Neither HVAC Duct Sizer nor Digiduct shows ads.

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

HVAC Duct Sizer ships an update every 6 months, and Digiduct every 2 months. Most recently, HVAC Duct Sizer was updated on September 17, 2026 and Digiduct on September 12, 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.*