# Convert Rai vs Engineering Calculator HVAC

The clearest difference is price: Engineering Calculator HVAC at Free against Convert Rai's $0.99. Convert Rai's advantage is update cadence (every 4 weeks vs every 6 months) and iOS requirement (13.0 vs 15.0). On ads, in-app purchases and device support there is nothing between them.

Engineering Calculator HVAC is free to download; Convert Rai costs $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Convert Rai ships an update every 4 weeks, Engineering Calculator HVAC every 6 months. The most recent releases landed on October 19, 2026 and October 8, 2026 respectively.

## The numbers

| Metric | Convert Rai | Engineering Calculator HVAC |
| --- | --- | --- |
| Price | $0.99 | **Free** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 4 weeks** | Every 6 months |
| Size | 17 MB | 19 MB |
| Requires iOS | **13.0** | 15.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Khanin Chomphusri](https://appshunter.io/developer/1657583243) | [aleksandr bronnikov](https://appshunter.io/developer/1885003900) |

## What reviewers say

### Convert Rai

[App page](https://appshunter.io/ios/app/convert-rai/id6444877065)

**Features:** macOS Compatibility

**In-app purchases:** none


### Engineering Calculator HVAC

[App page](https://appshunter.io/ios/app/engineering-calculator-hvac/id6760564633)

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

**In-app purchases:** none


## Frequently asked questions

### Is Convert Rai free?

Convert Rai costs $0.99, with no in-app purchases.

### Is Engineering Calculator HVAC free?

Engineering Calculator HVAC is free to download, with no in-app purchases.

### Do Convert Rai or Engineering Calculator HVAC have ads?

Neither Convert Rai nor Engineering Calculator HVAC shows ads.

### Which is updated more often, Convert Rai or Engineering Calculator HVAC?

Convert Rai ships an update every 4 weeks, and Engineering Calculator HVAC every 6 months. Most recently, Convert Rai was updated on October 19, 2026 and Engineering Calculator HVAC 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.*