# HVAC Duct Sizer vs Air Flow Conversion Calculator

The clearest difference is review sentiment: HVAC Duct Sizer at 63% against Air Flow Conversion Calculator's 0%. HVAC Duct Sizer also leads on update cadence (every 3 months vs every 47 months). Air Flow Conversion Calculator's advantage is in-app purchases (none vs 1) and rating (3.5 vs 3.1). On ratings volume, ads and device support there is nothing between them.

HVAC Duct Sizer costs $4.99 and Air Flow Conversion Calculator $2.99 up front. HVAC Duct Sizer sells 1 one-off in-app purchase. Air Flow Conversion Calculator asks for nothing beyond the download.

Air Flow Conversion Calculator holds the better App Store score, 3.5 against 3.1. Both are backed by a comparable volume of ratings — 9 and 11 respectively. Written reviews complicate that: 63% of HVAC Duct Sizer's written reviews are positive against 0% of Air Flow Conversion Calculator's, so the app with the better star average is not the one people write more warmly about.

HVAC Duct Sizer ships an update every 3 months, Air Flow Conversion Calculator every 47 months. The most recent releases landed on October 29, 2026 and October 22, 2026 respectively.

## The numbers

| Metric | HVAC Duct Sizer | Air Flow Conversion Calculator |
| --- | --- | --- |
| Price | $4.99 | **$2.99** |
| Rating | [3.1 (9 ratings)](https://appshunter.io/ios/app/hvac-duct-sizer/id317970395/reviews) | **[3.5 (11 ratings)](https://appshunter.io/ios/app/air-flow-conversion-calculator/id1375810553/reviews)** |
| Number of ratings | 9 | **11** |
| Positive reviews | **62.5% of reviews** | 0.0% of reviews |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Every 3 months** | Every 47 months |
| Monetization | **Free with in-app purchases** | Paid |
| Size | 1 MB | 8 MB |
| Requires iOS | 17.0 | **12.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | +4 | 4+ |
| Developer | [Carmel Software Corporation](https://appshunter.io/developer/317970398) | [Nitrio](https://appshunter.io/developer/321121189) |

## What reviewers say

### HVAC Duct Sizer

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

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 |


### Air Flow Conversion Calculator

[App page](https://appshunter.io/ios/app/air-flow-conversion-calculator/id1375810553)

Easily calculate air velocity and airflow volume for various duct types. Input dimensions and units, and get instant results for HVAC and ventilation applications.

**Highlights:** Calculate air velocity and airflow volume, Support for circular and rectangular ducts, Multiple unit options for velocity, volume, and dimensions, Instant result display, Useful for HVAC and ventilation

**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 Air Flow Conversion Calculator free?

Air Flow Conversion Calculator costs $2.99, with no in-app purchases.

### Which has better reviews, HVAC Duct Sizer or Air Flow Conversion Calculator?

Air Flow Conversion Calculator is rated higher. HVAC Duct Sizer averages 3.1 out of 5 from 9 ratings, while Air Flow Conversion Calculator averages 3.5 from 11 ratings.

### Do HVAC Duct Sizer or Air Flow Conversion Calculator have ads?

Neither HVAC Duct Sizer nor Air Flow Conversion Calculator shows ads.

### Which is updated more often, HVAC Duct Sizer or Air Flow Conversion Calculator?

HVAC Duct Sizer ships an update every 3 months, and Air Flow Conversion Calculator every 47 months. Most recently, HVAC Duct Sizer was updated on October 29, 2026 and Air Flow Conversion Calculator on October 22, 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.*