# DuctChecker vs Lupin meter

The clearest difference is price: Lupin meter at Free against DuctChecker's $6.99. Lupin meter also leads on iOS requirement (8.0 vs 15.0). On update cadence, ads, in-app purchases and device support there is nothing between them.

Lupin meter is free to download; DuctChecker costs $6.99 up front. Neither carries in-app purchases, so what you see is what you pay.

DuctChecker ships an update every 4 months, Lupin meter every 3 months. The most recent releases landed on October 24, 2026 and October 11, 2026 respectively.

## The numbers

| Metric | DuctChecker | Lupin meter |
| --- | --- | --- |
| Price | $6.99 | **Free** |
| Positive reviews | 0.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 4 months | **Every 3 months** |
| Monetization | Paid | — |
| Size | 23 MB | 6 MB |
| Requires iOS | 15.0 | **8.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [AIR DESIGN, INC.](https://appshunter.io/developer/923430781) | [Endo Lighting Corp.](https://appshunter.io/developer/1066146118) |

## What reviewers say

### 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


### Lupin meter

[App page](https://appshunter.io/ios/app/lupin-meter/id1256856500)

**In-app purchases:** none


## Frequently asked questions

### Is DuctChecker free?

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

### Is Lupin meter free?

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

### Do DuctChecker or Lupin meter have ads?

Neither DuctChecker nor Lupin meter shows ads.

### Which is updated more often, DuctChecker or Lupin meter?

DuctChecker ships an update every 4 months, and Lupin meter every 3 months. Most recently, DuctChecker was updated on October 24, 2026 and Lupin meter on October 11, 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.*