# ASHRAE DFDB Lite vs Fluence Design

The clearest difference is in-app purchases: ASHRAE DFDB Lite at none against Fluence Design's 1. ASHRAE DFDB Lite also leads on device support (3 vs 1) and iOS requirement (11.0 vs 17.0). On price, update cadence and ads there is nothing between them.

Both are free to download. Fluence Design sells 1 in-app purchase, starting at $9.99 per year. ASHRAE DFDB Lite asks for nothing beyond the download.

ASHRAE DFDB Lite ships an update every 6 weeks, Fluence Design every 3 weeks. Both last shipped on October 6, 2026.

## The numbers

| Metric | ASHRAE DFDB Lite | Fluence Design |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 0.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 6 weeks | **Every 3 weeks** |
| Monetization | Free | — |
| Size | 7 MB | 8 MB |
| Requires iOS | **11.0** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [ASHRAE, Inc.](https://appshunter.io/developer/375374912) | [Tripp Martin](https://appshunter.io/developer/1896282734) |

## What reviewers say

### ASHRAE DFDB Lite

[App page](https://appshunter.io/ios/app/ashrae-dfdb-lite/id6475053772)

Calculate pressure loss for a selection of ASHRAE duct fittings. Create projects, customize inputs, and generate reports with spreadsheet attachments. Supports both I-P and SI units and works on iPhone and iPad.

**Highlights:** Pressure loss calculations for ASHRAE fittings, Individual project creation, Customizable input parameters, Fitting code search feature, Display and email reports, I-P and SI unit support, iPhone and iPad compatible

**Features:** macOS Compatibility

**In-app purchases:** none


### Fluence Design

[App page](https://appshunter.io/ios/app/fluence-design/id6799210508)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Fluence Pro Annual | $9.99 | per year |


## Frequently asked questions

### Is ASHRAE DFDB Lite free?

ASHRAE DFDB Lite is free to download, with no in-app purchases.

### Is Fluence Design free?

Fluence Design is free to download, with in-app purchases available.

### Do ASHRAE DFDB Lite or Fluence Design have ads?

Neither ASHRAE DFDB Lite nor Fluence Design shows ads.

### Which is updated more often, ASHRAE DFDB Lite or Fluence Design?

ASHRAE DFDB Lite ships an update every 6 weeks, and Fluence Design every 3 weeks. Most recently, ASHRAE DFDB Lite was updated on October 6, 2026 and Fluence Design on October 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.*