# IN HVAC Calculator vs Flex Controller

The clearest difference is update cadence: IN HVAC Calculator at every 6 months against Flex Controller's every 13 months. IN HVAC Calculator also leads on iOS requirement (12.0 vs 15.0). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

IN HVAC Calculator ships an update every 6 months, Flex Controller every 13 months. The most recent releases landed on September 22, 2026 and October 8, 2026 respectively.

## The numbers

| Metric | IN HVAC Calculator | Flex Controller |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.2 (11 ratings)](https://appshunter.io/ios/app/in-hvac-calculator/id1219008229/reviews)** | — |
| Number of ratings | **11** | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 6 months** | Every 13 months |
| Monetization | Free | — |
| Size | 27 MB | 31 MB |
| Requires iOS | **12.0** | 15.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Gregory Enterprises](https://appshunter.io/developer/1157657878) | [Poolsure, a division of Aquasol Controllers, Inc.](https://appshunter.io/developer/1545322313) |

## What reviewers say

### IN HVAC Calculator

[App page](https://appshunter.io/ios/app/in-hvac-calculator/id1219008229)

This app provides HVAC inspection tools and guidelines for home inspectors. It helps estimate equipment age, size, and requirements, giving inspectors confidence in their reports.

**Highlights:** Equipment circuit requirements calculator, AC tonnage estimation by model number, HVAC manufacture date lookup, Combustion air requirements guide, General HVAC reference information

**Features:** macOS Compatibility

**In-app purchases:** none


### Flex Controller

[App page](https://appshunter.io/ios/app/flex-controller/id6741504172)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is IN HVAC Calculator free?

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

### Is Flex Controller free?

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

### Do IN HVAC Calculator or Flex Controller have ads?

Neither IN HVAC Calculator nor Flex Controller shows ads.

### Which is updated more often, IN HVAC Calculator or Flex Controller?

IN HVAC Calculator ships an update every 6 months, and Flex Controller every 13 months. Most recently, IN HVAC Calculator was updated on September 22, 2026 and Flex Controller 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.*