# CTS vs PreHeat

The clearest difference is in-app purchases: CTS at none against PreHeat's 1. PreHeat's advantage is update cadence (fortnightly vs every 8 months). On price, ads, device support and iOS requirement there is nothing between them.

Both are free to download. PreHeat sells 1 one-off in-app purchase. CTS asks for nothing beyond the download.

CTS ships an update every 8 months, PreHeat fortnightly. The most recent releases landed on September 17, 2026 and September 15, 2026 respectively.

## The numbers

| Metric | CTS | PreHeat |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (4 ratings)](https://appshunter.io/ios/app/cts-cincinnati-test-systems/id1033877646/reviews)** | — |
| Number of ratings | **4** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 8 months | **Fortnightly** |
| Monetization | Free | — |
| Size | 2 MB | 4 MB |
| Requires iOS | 13.0 | 13.0 |
| Devices | iPhone, iPad, iPod | **iPhone, iPad, iPod, Mac** |
| Age rating | 4+ | 4+ |
| Developer | [Cincinnati Test Systems](https://appshunter.io/developer/1033877645) | [Shabbir Ahmed](https://appshunter.io/developer/1083166021) |

## What reviewers say

### CTS

[App page](https://appshunter.io/ios/app/cts-cincinnati-test-systems/id1033877646)

Calculate leak test cycle times using leak rate, volume, and pressure drop. This tool also offers conversions for various units of volume, pressure, and leak rates. It's designed for professionals in leak testing.

**Highlights:** Leak test cycle time calculation, Leak rate, volume, pressure drop variables, Volume conversions, Pressure conversions, Bubble to leak rate conversions, Length and area conversions

**Features:** macOS Compatibility

**In-app purchases:** none


### PreHeat

[App page](https://appshunter.io/ios/app/preheat/id6461216985)

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Non Consumable Subscription | $3.99 | one-time |


## Frequently asked questions

### Is CTS free?

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

### Is PreHeat free?

PreHeat is free to download, with in-app purchases available.

### Do CTS or PreHeat have ads?

Neither CTS nor PreHeat shows ads.

### Which is updated more often, CTS or PreHeat?

CTS ships an update every 8 months, and PreHeat fortnightly. Most recently, CTS was updated on September 17, 2026 and PreHeat on September 15, 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.*