# HVAC Pipe Sizer - Gas Low — Low pressure gas pipe calcs

> Calculates low-pressure gas pipe sizes based on flow and pressure parameters. (iPhone/iPad app by Carmel Software Corporation.)

- Source: https://appshunter.io/ios/app/hvac-pipe-sizer-gas-low/id341688321 (this page in markdown: same URL + `.md`)
- Developer: [Carmel Software Corporation](https://appshunter.io/developer/317970398)
- Category: Productivity, Utilities
- Price: $4.99
- Rating: 5.00/5 from 2 App Store ratings · 2 written reviews indexed
- Age rating: 4+
- Requires: iOS 15.6 · 17 MB
- Languages: American English
- Released: 2009-12-03
- Data updated: 2026-08-27
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/hvac-pipe-sizer-gas-low/id341688321/reviews.md

## What is HVAC Pipe Sizer?

The "HVAC Pipe Sizer - Gas Low" application allows you to quickly size a simple low pressure (less than 1.5psi) gas piping system by inputting a number of piping and gas properties.

You can specify the total gas flow in cuft/hr (CubicM/hr) and one of either pressure drop (in. wg or Pa), pipe internal diameter (inches) or gas velocity (ft/s) parameters. The results include both the exact and nominal pipe diameters and the calculated velocity and total pipe equivalent length. If you are analyzing an existing pipe system, there is an option to input the existing pipe internal diameter and one of either pressure drop or gas velocity parameters to derive the calculated gas flow and other remaining properties.

You can specify additional parameters such as the type of gas, various properties of the gas, the pipe material type, the total length of pipe, quantities for up to 11 different types of pipe fittings, and much more. You can also choose to display values in either english or metric units.

This application includes built-in pipe fitting equivalent length and nominal pipe sizing tables for a wide variety of pipe material types and diameters.

The "HVAC Pipe Sizer - Gas Low" application uses slider controls that allow you to quickly increment or decrement the input values and immediately observe the calculated results. You can also manually input exact values.

All values can be displayed in English (IP) and Metric (SI) units.

This app now includes the HVAC Equipment Locator. Click here for details: http://bit.ly/1yTq539 

This application was designed by Carmel Software Corporation, a leader in HVAC design software since 1995. In fact, Autodesk (the makers of AutoCAD) acquired our load calculation software and incorporated it into their leading 3D modeling software called Revit. 

We also offer the following additional applications for the iPhone/iPad:

1. HVAC Duct Sizer
2. HVAC Pipe Sizer – Gas Low Pressure
3. HVAC Pipe Sizer - Gas High Pressure
4. HVAC Pipe Sizer – Liquid
5. HVAC Pipe Sizer – Steam
6. Steam Tables
7. Psychrometric Plus
8. Psychrometric LT
9. HVAC Pipe Sizer Plus
10. HVAC Pipe Sizer Gas Plus
11. HVAC Toolkit
12. HVAC Toolkit Ultimate
13. HVAC Residential Load Calcs
14. HVAC Load Plus
15. HVAC Equipment Locator
16. ASHRAE Duct Fitting Database
17. ASHRAE 62.1 Ventilation Load Calcs
18. HVAC Psych HD
19. HVAC ResLoad-J
20. HVAC Residential Load Calcs HD

## Key features

- Low pressure gas pipe sizing
- Input flow, pressure drop, diameter, or velocity
- Calculate exact and nominal pipe diameters
- Specify gas and pipe properties
- Includes pipe fitting equivalent lengths
- English and metric unit display

## Recent user reviews (2 of 2)

All indexed reviews: https://appshunter.io/ios/app/hvac-pipe-sizer-gas-low/id341688321/reviews.md

### 5/5 — Lots of functionality

*2010-05-09*

This app has lots of great functionality. Allows me to input gas flow then either input pressure drop, diameter, or velocity. Also, allows me to size according to diameter and pressure drop to see what the expected flow rate is.

I also like how it stores all my results, so when I close it and come back to it later on, the same values are there. 

Very useful.

### 5/5 — Useful for field work

*2010-05-09*

Great little app for approximating low pressure gas pipe sizes out in the field. I often go to homes to diagnose heating issues and want to make sure the gas pipes are the correct size (you won't believe how many are over or under sized). Anyway, this app helps me diagnose those issues. I highly recommend it.

## Frequently asked questions about HVAC Pipe Sizer

### What is HVAC Pipe Sizer - Gas Low used for?

HVAC Pipe Sizer - Gas Low is used to quickly size simple low-pressure (under 1.5psi) gas piping systems. It calculates pipe diameters, velocity, and equivalent length based on various input parameters.

### What types of inputs can I provide for HVAC Pipe Sizer - Gas Low?

You can input total gas flow, pressure drop, pipe internal diameter, or gas velocity. The app then calculates the remaining parameters.

### Does HVAC Pipe Sizer - Gas Low support different units?

Yes, all values can be displayed in either English (IP) or Metric (SI) units, allowing for flexible use in different regions and standards.

### What information does HVAC Pipe Sizer - Gas Low include about pipe fittings?

The application includes built-in tables for pipe fitting equivalent lengths for a wide variety of pipe material types and diameters, aiding in accurate calculations.

### How does HVAC Pipe Sizer - Gas Low handle user input?

It features slider controls for quick adjustments of input values and immediate observation of results, alongside the ability to manually input exact values.

### Is HVAC Pipe Sizer - Gas Low suitable for analyzing existing pipe systems?

Yes, there is an option to input existing pipe internal diameter and either pressure drop or gas velocity to derive the calculated gas flow and other properties of an existing system.

### What is the price of HVAC Pipe Sizer - Gas Low?

HVAC Pipe Sizer - Gas Low is a paid application priced at $4.99.

### How often is HVAC Pipe Sizer - Gas Low updated?

The latest version, 4.76, was last updated on December 5, 2025, indicating active development and maintenance by the developer.

## Version history (last 5 releases)

### 4.76 — 2025-12-05

1. Added a Share button to the iPhone and iPad versions of the app, so you can now text, email, and download reports.
2. Updated help.
3. Optimized for iOS 26.

### 4.5 — 2023-03-09

1. Optimized for iOS 16 and iPhone 14
2. Updated help

### 4.0 — 2021-11-01

1. Optimized for iOS 15 and iPhone 13
2. Updated help

### 3.8 — 2020-07-31

Updated Google Analytics and Crashlytics

### 3.7 — 2020-06-24

Updated the app launch screen per new Apple iOS guidelines.

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## More apps by Carmel Software Corporation

- [HVAC Duct Sizer](https://appshunter.io/ios/app/hvac-duct-sizer/id317970395)
- [HVAC Pipe Sizer - Liquid](https://appshunter.io/ios/app/hvac-pipe-sizer-liquid/id325069065)
- [HVAC Pipe Sizer - Steam](https://appshunter.io/ios/app/hvac-pipe-sizer-steam/id336112747)
- [Steam Tables](https://appshunter.io/ios/app/steam-tables/id339948012)
- [HVAC Pipe Sizer - Gas High](https://appshunter.io/ios/app/hvac-pipe-sizer-gas-high/id341828523)

All apps by Carmel Software Corporation: https://appshunter.io/developer/317970398

## Related topics

[pipe sizing calc hvac](https://appshunter.io/ios/topics/pipe-sizing-calc-hvac)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-27.*