# Navisizer vs Ductulator

The clearest difference is price: Navisizer at Free against Ductulator's $3.99. Ductulator's advantage is rating (4.7 vs 2.4) and review sentiment (50% vs 13%). On update cadence, ads, in-app purchases and monetization model there is nothing between them.

Navisizer is free to download; Ductulator costs $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Ductulator holds the better App Store score, 4.7 against 2.4. That said, the two scores are not equally well evidenced: Ductulator has 317 ratings behind it against 26, so its average is the more settled of the two. Written reviews point the same way: 13% of Navisizer's written reviews are positive against 50% of Ductulator's.

Navisizer ships an update every 4 months, Ductulator every 2 months. The most recent releases landed on June 1, 2026 and September 22, 2026 respectively.

## The numbers

| Metric | Navisizer | Ductulator |
| --- | --- | --- |
| Price | **Free** | $3.99 |
| Rating | [2.4 (26 ratings)](https://appshunter.io/ios/app/navisizer/id1327385997/reviews) | **[4.7 (317 ratings)](https://appshunter.io/ios/app/ductulator-duct-sizing/id1474939475/reviews)** |
| Number of ratings | 26 | **317** |
| Positive reviews | 12.5% of reviews | **50.0% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 4 months | **Every 2 months** |
| Monetization | Free | Free |
| Best chart rank | — | **#36** |
| Size | 21 MB | 1 MB |
| Requires iOS | **17.2** | 18.6 |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Navien, Inc.](https://appshunter.io/developer/1327385996) | [Wassim Murr](https://appshunter.io/developer/1474939474) |

## What reviewers say

### Navisizer

[App page](https://appshunter.io/ios/app/navisizer/id1327385997)

This app helps size domestic hot water heating systems for residential and commercial use. It calculates operating costs, savings, and generates comprehensive job specifications for Navien NPE Series tankless water heaters.

**Highlights:** Residential system sizing, Operating cost and savings calculation, Commercial application sizing (ASHRAE Hunter Curve), Tankless and tankless with storage solutions, Comprehensive job specification output, Save, print, or email system specs

**Features:** macOS Compatibility

**In-app purchases:** none


### Ductulator

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

**Currently charting:** #36 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 Navisizer free?

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

### Is Ductulator free?

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

### Which has better reviews, Navisizer or Ductulator?

Ductulator is rated higher. Navisizer averages 2.4 out of 5 from 26 ratings, while Ductulator averages 4.7 from 317 ratings.

### Do Navisizer or Ductulator have ads?

Neither Navisizer nor Ductulator shows ads.

### Which is updated more often, Navisizer or Ductulator?

Navisizer ships an update every 4 months, and Ductulator every 2 months. Most recently, Navisizer was updated on June 1, 2026 and Ductulator on September 22, 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.*