# HVAC Duct Sizer vs Bluon HVAC

The clearest difference is price: Bluon HVAC at Free against HVAC Duct Sizer's $4.99. Bluon HVAC also leads on rating (4.8 vs 3.1) and in-app purchases (none vs 1). HVAC Duct Sizer's advantage is ads (none vs shown). On review sentiment and device support there is nothing between them.

Bluon HVAC is free to download; HVAC Duct Sizer costs $4.99 up front. HVAC Duct Sizer sells 1 one-off in-app purchase. Bluon HVAC asks for nothing beyond the download.

Bluon HVAC holds the better App Store score, 4.8 against 3.1. That said, the two scores are not equally well evidenced: Bluon HVAC has 4.5K ratings behind it against 9, so its average is the more settled of the two. Written reviews complicate that: 63% of HVAC Duct Sizer's written reviews are positive against 55% of Bluon HVAC's, so the app with the better star average is not the one people write more warmly about.

HVAC Duct Sizer ships an update every 3 months, Bluon HVAC monthly. The most recent releases landed on October 31, 2026 and November 6, 2026 respectively.

## The numbers

| Metric | HVAC Duct Sizer | Bluon HVAC |
| --- | --- | --- |
| Price | $4.99 | **Free** |
| Rating | [3.1 (9 ratings)](https://appshunter.io/ios/app/hvac-duct-sizer/id317970395/reviews) | **[4.8 (4.5K ratings)](https://appshunter.io/ios/app/bluon-hvac/id1357521880/reviews)** |
| Number of ratings | 9 | **4.5K** |
| Positive reviews | **62.5% of reviews** | 54.6% of reviews |
| In-app purchases | Yes | **No** |
| Ads | **No** | Yes |
| Update frequency | Every 3 months | **Monthly** |
| Monetization | Free with in-app purchases | **Ad-supported** |
| Size | 1 MB | 170 MB |
| Requires iOS | 17.0 | **15.1** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | +4 | 4+ |
| Developer | [Carmel Software Corporation](https://appshunter.io/developer/317970398) | [Bluon, Inc.](https://appshunter.io/developer/1357521879) |

## What reviewers say

### HVAC Duct Sizer

[App page](https://appshunter.io/ios/app/hvac-duct-sizer/id317970395)

This app provides quick and simple HVAC duct sizing analysis. It allows users to calculate duct dimensions based on airflow or existing dimensions, and can also determine a range of duct sizes. Results can be emailed for further analysis.

**Highlights:** Duct sizing by airflow, Duct sizing by dimensions, Range of duct sizes calculation, Rectangular, round, and oval duct shapes, English and Metric unit options, Email results with CSV attachment, HVAC Equipment Locator

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| HVAC Equipment Locator | $9.99 | one-time |


### Bluon HVAC

[App page](https://appshunter.io/ios/app/bluon-hvac/id1357521880)

Access a vast database of HVAC-R and plumbing unit documentation, including specs, manuals, and replacement parts. Get AI-powered troubleshooting and connect with live veteran technicians for support.

**Highlights:** 35,000,000+ HVAC unit database, Model specs, age, and warranty info, Original parts and replacement options, AI-powered troubleshooting (Master Mechanic), Live veteran technician support line, Supplier contact and ordering

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

**In-app purchases:** none

**What reviewers like**

- 🤖 Helpful tech support
- 💯 Comprehensive database of manuals and information
- 🛠️ Useful tools and calculators
- 🤝 Great customer service

**What reviewers complain about**

- 💰 Paywall for advanced features
- 🔒 Limited access without company account
- 🔍 Missing manuals for some equipment models
- 🗣️ Removal of helpful forums

**Reported bugs**

- Login/password reset issues
- Frequent crashes or loading problems

**Requested features**

- Individual technician subscription option
- More comprehensive coverage of HVAC equipment models
- Ability to access full manuals without restrictions


## Frequently asked questions

### Is HVAC Duct Sizer free?

HVAC Duct Sizer costs $4.99, and also offers in-app purchases.

### Is Bluon HVAC free?

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

### Which has better reviews, HVAC Duct Sizer or Bluon HVAC?

Bluon HVAC is rated higher. HVAC Duct Sizer averages 3.1 out of 5 from 9 ratings, while Bluon HVAC averages 4.8 from 4.5K ratings.

### Do HVAC Duct Sizer or Bluon HVAC have ads?

Bluon HVAC shows ads; HVAC Duct Sizer does not.

### Which is updated more often, HVAC Duct Sizer or Bluon HVAC?

HVAC Duct Sizer ships an update every 3 months, and Bluon HVAC monthly. Most recently, HVAC Duct Sizer was updated on October 31, 2026 and Bluon HVAC on November 6, 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.*