# HVAC Formulator vs Ductulator

The clearest difference is rating: Ductulator at 4.7 against HVAC Formulator's 2.0. Ductulator also leads on review sentiment (50% vs 9%) and in-app purchases (none vs 1). On update cadence, ads, device support and iOS requirement there is nothing between them.

HVAC Formulator costs $4.99 and Ductulator $3.99 up front. HVAC Formulator sells 1 one-off in-app purchase. Ductulator asks for nothing beyond the download.

Ductulator holds the better App Store score, 4.7 against 2.0. That said, the two scores are not equally well evidenced: Ductulator has 317 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 9% of HVAC Formulator's written reviews are positive against 50% of Ductulator's.

Both ship on a similar rhythm, roughly every 2 months. The most recent releases landed on September 5, 2026 and September 22, 2026 respectively.

## The numbers

| Metric | HVAC Formulator | Ductulator |
| --- | --- | --- |
| Price | $4.99 | **$3.99** |
| Rating | [2.0 (1 ratings)](https://appshunter.io/ios/app/hvac-formulator/id318898907/reviews) | **[4.7 (317 ratings)](https://appshunter.io/ios/app/ductulator-duct-sizing/id1474939475/reviews)** |
| Number of ratings | 1 | **317** |
| Positive reviews | 9.1% of reviews | **50.0% of reviews** |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 2 months | Every 2 months |
| Monetization | Paid | **Free** |
| Best chart rank | #197 | **#40** |
| Size | 73 MB | 1 MB |
| Requires iOS | 18.6 | 18.6 |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Historycentral.com](https://appshunter.io/developer/1744330560) | [Wassim Murr](https://appshunter.io/developer/1474939474) |

## What reviewers say

### HVAC Formulator

[App page](https://appshunter.io/ios/app/hvac-formulator/id318898907)

**Currently charting:** #197 Top Paid · Productivity (US App Store)

This app provides HVAC professionals with over 900 essential formulas and calculations for load calculations and system design. It supports both US and Metric units, offers instant switching, and includes 23 calculator categories and over 460 unit conversions. Designed for field use, it works offline and allows users to save and share results.

**Highlights:** Over 900 formulas and calculations, US & Metric unit support, 23 calculator categories, 460+ unit conversions, 8 temperature scales, Offline functionality, Save and share results

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| HVAC Pro | $3.99 | one-time |


### Ductulator

[App page](https://appshunter.io/ios/app/ductulator-duct-sizing/id1474939475)

**Currently charting:** #40 Top Paid · Productivity (US App Store)

Instantly calculate HVAC duct sizes based on airflow, friction rate, or velocity. This tool provides accurate duct dimensions in seconds without needing charts, supporting various duct types and units.

**Highlights:** Instant duct sizing, Friction rate or velocity calculation, Multiple valid duct dimensions, IP and SI units support, Detailed sizing mode, Rectangular, circular, and flexible ducts

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

**In-app purchases:** none


## Frequently asked questions

### Is HVAC Formulator free?

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

### Is Ductulator free?

Ductulator costs $3.99, with no in-app purchases.

### Which has better reviews, HVAC Formulator or Ductulator?

Ductulator is rated higher. HVAC Formulator averages 2.0 out of 5 from 1 ratings, while Ductulator averages 4.7 from 317 ratings.

### Do HVAC Formulator or Ductulator have ads?

Neither HVAC Formulator nor Ductulator shows ads.

### Which is updated more often, HVAC Formulator or Ductulator?

HVAC Formulator ships an update every 2 months, and Ductulator every 2 months. Most recently, HVAC Formulator was updated on September 5, 2026 and Ductulator on September 22, 2026.

### Which is more popular, HVAC Formulator or Ductulator?

HVAC Formulator currently peaks at #197 in the App Store charts, and Ductulator at #40. Chart position reflects recent download velocity rather than total install base.

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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.*