# AirDiffuser vs DuctChecker

The clearest difference is update cadence: DuctChecker at every 4 months against AirDiffuser's every 60 months. AirDiffuser's advantage is price ($2.99 vs $6.99) and iOS requirement (9.0 vs 15.0). On ads, in-app purchases, monetization model and device support there is nothing between them.

AirDiffuser costs $2.99 and DuctChecker $6.99 up front. Neither carries in-app purchases, so what you see is what you pay.

AirDiffuser ships an update every 60 months, DuctChecker every 4 months. The most recent releases landed on September 28, 2026 and October 8, 2026 respectively.

## The numbers

| Metric | AirDiffuser | DuctChecker |
| --- | --- | --- |
| Price | **$2.99** | $6.99 |
| Rating | **[1.0 (1 ratings)](https://appshunter.io/ios/app/airdiffuser/id441746795/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | — | 0.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 60 months | **Every 4 months** |
| Monetization | Paid | Paid |
| Size | 4 MB | 23 MB |
| Requires iOS | **9.0** | 15.0 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Technical Data Service Co.,Ltd.](https://appshunter.io/developer/441746798) | [AIR DESIGN, INC.](https://appshunter.io/developer/923430781) |

## What reviewers say

### AirDiffuser

[App page](https://appshunter.io/ios/app/airdiffuser/id441746795)

Quickly select air ceiling diffusers for HVAC systems. Input wind amount to calculate apparatus size and wind velocity. Supports various diffuser types and customizable settings for site and meeting use.

**Highlights:** Easy apparatus size selection by wind amount input, Supports various diffuser types (Round, Square, BL, CL, etc.), Adjustable aperture rate and wind velocity, Reverse calculation of wind amount, Metric system calculations, Calculations for BL and CL round length

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

**In-app purchases:** none


### DuctChecker

[App page](https://appshunter.io/ios/app/ductchecker/id933593987)

Easily calculate duct dimensions using various engineering methods like constant pressure, static pressure regain, total pressure, and velocity. This tool simplifies complex duct design calculations, typically found in flow diagrams or slide rules.

**Highlights:** Constant pressure method calculation, Static pressure regain method, Total pressure method, Velocity method, Duct dimension determination, Simplified duct design

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

**In-app purchases:** none


## Frequently asked questions

### Is AirDiffuser free?

AirDiffuser costs $2.99, with no in-app purchases.

### Is DuctChecker free?

DuctChecker costs $6.99, with no in-app purchases.

### Do AirDiffuser or DuctChecker have ads?

Neither AirDiffuser nor DuctChecker shows ads.

### Which is updated more often, AirDiffuser or DuctChecker?

AirDiffuser ships an update every 60 months, and DuctChecker every 4 months. Most recently, AirDiffuser was updated on September 28, 2026 and DuctChecker on October 8, 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.*