# HVAC vs CURB deviation

The clearest difference is price: CURB deviation at Free against HVAC's $4.99. CURB deviation also leads on update cadence (every 3 weeks vs every 5 months). HVAC's advantage is chart position (#188 vs unranked). On ads, in-app purchases, device support and iOS requirement there is nothing between them.

CURB deviation is free to download; HVAC costs $4.99 up front. Neither carries in-app purchases, so what you see is what you pay.

HVAC ships an update every 5 months, CURB deviation every 3 weeks. The most recent releases landed on September 11, 2026 and September 19, 2026 respectively.

## The numbers

| Metric | HVAC | CURB deviation |
| --- | --- | --- |
| Price | $4.99 | **Free** |
| Rating | **[4.0 (1 ratings)](https://appshunter.io/ios/app/hvac-calculator/id602391404/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 5 months | **Every 3 weeks** |
| Monetization | Paid | — |
| Best chart rank | **#188** | — |
| Size | 14 MB | 16 MB |
| Requires iOS | 16.0 | **15.1** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Trond Rossvoll](https://appshunter.io/developer/571419518) | [CoPro Live AS](https://appshunter.io/developer/788462775) |

## What reviewers say

### HVAC

[App page](https://appshunter.io/ios/app/hvac-calculator/id602391404)

**Currently charting:** #188 Top Paid · Productivity (US App Store)

This app provides quick and easy calculations for HVAC professionals and enthusiasts. It simplifies complex formulas for energy use, airflow, and duct dimensions, making them accessible on your iPhone or iPad.

**Highlights:** SFP calculations, Heat recovery efficiency, Air velocity in ducts, Duct dimensioning, Pressure drop calculations, Equivalent diameters

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

**In-app purchases:** none


### CURB deviation

[App page](https://appshunter.io/ios/app/curb-deviation/id1362532396)

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

**In-app purchases:** none


## Frequently asked questions

### Is HVAC free?

HVAC costs $4.99, with no in-app purchases.

### Is CURB deviation free?

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

### Do HVAC or CURB deviation have ads?

Neither HVAC nor CURB deviation shows ads.

### Which is updated more often, HVAC or CURB deviation?

HVAC ships an update every 5 months, and CURB deviation every 3 weeks. Most recently, HVAC was updated on September 11, 2026 and CURB deviation on September 19, 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.*