# PFM1000 vs ASHRAE DFDB Lite

The clearest difference is update cadence: ASHRAE DFDB Lite at every 6 weeks against PFM1000's every 3 months. ASHRAE DFDB Lite also leads on iOS requirement (11.0 vs 17.0). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

PFM1000 ships an update every 3 months, ASHRAE DFDB Lite every 6 weeks. The most recent releases landed on October 17, 2026 and October 23, 2026 respectively.

## The numbers

| Metric | PFM1000 | ASHRAE DFDB Lite |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[1.0 (2 ratings)](https://appshunter.io/ios/app/ashrae-dfdb-lite/id6475053772/reviews)** |
| Number of ratings | — | **2** |
| Positive reviews | — | 0.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 3 months | **Every 6 weeks** |
| Monetization | — | Free |
| Size | 43 MB | 7 MB |
| Requires iOS | 17.0 | **11.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [SV Technics](https://appshunter.io/developer/1384360031) | [ASHRAE, Inc.](https://appshunter.io/developer/375374912) |

## What reviewers say

### PFM1000

[App page](https://appshunter.io/ios/app/pfm1000/id1445659388)

**In-app purchases:** none


### 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


## Frequently asked questions

### Is PFM1000 free?

PFM1000 is free to download, with no in-app purchases.

### Is ASHRAE DFDB Lite free?

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

### Do PFM1000 or ASHRAE DFDB Lite have ads?

Neither PFM1000 nor ASHRAE DFDB Lite shows ads.

### Which is updated more often, PFM1000 or ASHRAE DFDB Lite?

PFM1000 ships an update every 3 months, and ASHRAE DFDB Lite every 6 weeks. Most recently, PFM1000 was updated on October 17, 2026 and ASHRAE DFDB Lite on October 23, 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.*