# Calc pH vs Heat Exchanger Area

The clearest difference is price: Calc pH at Free against Heat Exchanger Area's $1.99. Calc pH also leads on iOS requirement (9.0 vs 16.1). Heat Exchanger Area's advantage is update cadence (every 28 months vs every 59 months). On ads, in-app purchases and device support there is nothing between them.

Calc pH is free to download; Heat Exchanger Area costs $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Calc pH ships an update every 59 months, Heat Exchanger Area every 28 months. The most recent releases landed on November 1, 2026 and October 1, 2026 respectively.

## The numbers

| Metric | Calc pH | Heat Exchanger Area |
| --- | --- | --- |
| Price | **Free** | $1.99 |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 59 months | **Every 28 months** |
| Size | 0 MB | 1 MB |
| Requires iOS | **9.0** | 16.1 |
| Devices | iPhone, iPod | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [ZOFTERM](https://appshunter.io/developer/557950548) | [Imran Pinjara](https://appshunter.io/developer/1484488781) |

## What reviewers say

### Calc pH

[App page](https://appshunter.io/ios/app/calc-ph/id566354963)

**Features:** macOS Compatibility

**In-app purchases:** none


### Heat Exchanger Area

[App page](https://appshunter.io/ios/app/heat-exchanger-area/id1490690839)

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

**In-app purchases:** none


## Frequently asked questions

### Is Calc pH free?

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

### Is Heat Exchanger Area free?

Heat Exchanger Area costs $1.99, with no in-app purchases.

### Do Calc pH or Heat Exchanger Area have ads?

Neither Calc pH nor Heat Exchanger Area shows ads.

### Which is updated more often, Calc pH or Heat Exchanger Area?

Calc pH ships an update every 59 months, and Heat Exchanger Area every 28 months. Most recently, Calc pH was updated on November 1, 2026 and Heat Exchanger Area on October 1, 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.*