# Ductulator vs EraSpark AI

The clearest difference is price: EraSpark AI at Free against Ductulator's $3.99. EraSpark AI also leads on rating (5.0 vs 4.7) and iOS requirement (15.6 vs 18.6). Ductulator's advantage is in-app purchases (none vs 1) and ratings volume (353 vs 1). On update cadence, ads and device support there is nothing between them.

EraSpark AI is free to download; Ductulator costs $3.99 up front. EraSpark AI sells 1 in-app purchase, starting at $9.99 per month. Ductulator asks for nothing beyond the download.

EraSpark AI holds the better App Store score, 5.0 against 4.7. That said, the two scores are not equally well evidenced: Ductulator has 353 ratings behind it against 1, so its average is the more settled of the two.

Both ship on a similar rhythm, roughly every 2 months. The most recent releases landed on October 25, 2026 and October 1, 2026 respectively.

## The numbers

| Metric | Ductulator | EraSpark AI |
| --- | --- | --- |
| Price | $3.99 | **Free** |
| Rating | [4.7 (353 ratings)](https://appshunter.io/ios/app/ductulator-duct-sizing/id1474939475/reviews) | **[5.0 (1 ratings)](https://appshunter.io/ios/app/eraspark-ai/id6757258982/reviews)** |
| Number of ratings | **353** | 1 |
| Positive reviews | 50.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 2 months | Every 2 months |
| Monetization | **Free** | Freemium |
| Best chart rank | **#117** | — |
| Size | 1 MB | 63 MB |
| Requires iOS | 18.6 | **15.6** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Wassim Murr](https://appshunter.io/developer/1474939474) | [Richardson Medor](https://appshunter.io/developer/1865648248) |

## What reviewers say

### Ductulator

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

**Currently charting:** #117 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

**What reviewers like**

- 👍 Very helpful for duct sizing
- 👍 Easy to use in the field
- 👍 Saves time
- 👍 Seamless imperial/metric transitions
- 👍 Excellent tool for duct design

**What reviewers complain about**

- 👎 App should be free
- 👎 Functionality is pointless for some needs
- 👎 Doesn't help with traditional residential HVAC duct sizing
- 👎 App is a scam
- 👎 Decimal point doesn't work

**Reported bugs**

- Decimal point doesn't work on calculator
- New flex option isn't working properly
- Friction rate can't be changed in the latest version
- Skips duct sizes (e.g., 24-26)

**Requested features**

- Ability to pick duct size and see CFM
- Include flat oval ducts
- Option to select round or square duct
- Ability to enter duct size and get CFM
- Option for flex duct


### EraSpark AI

[App page](https://appshunter.io/ios/app/eraspark-ai/id6757258982)

An intelligent assistant offering three distinct modes: Past, Present, and Future. It helps users explore historical context, get real-time assistance, and discover forward-looking insights. Supports AI conversations, image and PDF analysis, and voice input.

**Highlights:** Past Mode for historical context, Present Mode for real-time assistance, Future Mode for forward-looking insights, AI-powered conversations, Image and PDF analysis, Voice input support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| EraSpark Pro | $9.99 | per month |


## Frequently asked questions

### Is Ductulator free?

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

### Is EraSpark AI free?

EraSpark AI is free to download, with in-app purchases available.

### Which has better reviews, Ductulator or EraSpark AI?

EraSpark AI is rated higher. Ductulator averages 4.7 out of 5 from 353 ratings, while EraSpark AI averages 5.0 from 1 ratings.

### Do Ductulator or EraSpark AI have ads?

Neither Ductulator nor EraSpark AI shows ads.

### Which is updated more often, Ductulator or EraSpark AI?

Ductulator ships an update every 2 months, and EraSpark AI every 2 months. Most recently, Ductulator was updated on October 25, 2026 and EraSpark AI on October 1, 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.*