HVAC Duct Sizer8.5 - App Store

The HVAC Duct Sizer app is the #1 selling duct sizing application for the Apple iPhone and iPad. Tens of thousands of happy users have downloaded this useful application for performing quick and simple duct sizing analysis.

The HVAC Duct Sizer is a universal duct sizing app so that it works on both the iPhone and iPad and adjusts its screen size accordingly.

Just a couple of comments from our users:

"I'll be presenting your iPhone program to my HVAC class as an easy compact tool to have in hand when making sales and service calls." - R. Black

"I like this app and use it daily" - V. Joe

The Duct Sizer application allows you to quickly size one HVAC duct run or a range of duct sizes using the constant friction method. Think of this application as a digital version of the classic Trane Ductulator.

In the "Size by Airflow" mode, you can specify the total airflow in CFM (or L/s), the aspect ratio and one of either the velocity of air or the friction loss per 100 feet (30 meters). The results include both the exact and rounded height and width (or diameter) dimensions and the calculated velocity and friction loss.

In the "Size by Dimensions" mode, you can analyze an existing duct system. There are options to input the existing duct dimensions and one of either the airflow or velocity values to derive the calculated duct friction loss.

In the "Range of Duct Sizes" mode, you can specify minimum and maximum friction loss and airflow values to display a range of duct sizes that fall in between the friction loss bounds.

You can specify additional parameters such as the duct shape (rectangular, round, or oval), the air temperature and the air pressure. You can also choose to display values in either English (IP) or Metric (SI) units.

This application uses slider controls that allow you to quickly increment or decrement the input values and immediately observe the calculated results.

Finally, you can email all of the inputs and results from all 3 input modes to perform further analysis using your desktop computer. The email includes a PDF report, HTML text and a .CSV attachment that can be imported into any popular spreadsheet.

The "HVAC Duct Sizer" 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. In addition, we developed a number of customized apps for ASHRAE, DNV GL, and other organizations.

We also offer the following additional apps for the iPhone and iPad:

1. HVAC Residential Load Calcs for iPhone and iPad
2. HVAC Quick Load Plus
3. HVAC Quick Load
4. HVAC Toolkit
5. HVAC Pipe Sizer - Gas Low Pressure
6. HVAC Pipe Sizer - Gas High Pressure
7. HVAC Pipe Sizer - Liquid
8. HVAC Pipe Sizer - Steam
9. Steam Tables
10. Psychrometric Plus
11. Psychrometric LT
12. HVAC Pipe Sizer Plus
13. HVAC Pipe Sizer Gas Plus
14. HVAC Toolkit Ultimate
15. HVAC Equipment Locator
16. HVAC ResLoad-J
17. HVAC Psych HD

Version History 1. A modernized interface built around Apple's latest UI/UX guidelines, including a full iPad layout.
2. Reports can be sent as PDF, CSV (Excel), and HTML and by email, text message, or any other Share option.
3. A color picker lets you choose the color of the calculated output values.
4. Fully updated and formatted help.
5. Many smaller refinements throughout.
6. Fixed bug in .csv output where a comma in a number (i.e. - 7,400) splits it into separate cells. 8.5 Sep 24 1. A modernized interface built around Apple's latest UI/UX guidelines, including a full iPad layout.
2. Reports can be sent as PDF, CSV (Excel), and HTML and by email, text message, or any other Share option.
3. A color picker lets you choose the color of the calculated output values.
4. Fully updated and formatted help.
5. Many smaller refinements throughout. 8.4 Sep 15 1. Fixed crashing issue in Range of Duct Sizes form on iPad version.
2. Updated help. 7.3 Feb 16 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. 7.1 11/30/2025 1. Fixed issue with Global Settings form crashing on iPad with iOS 8.x or above. 7.0 10/28/2025 1. Added Share button to iPad version so user can share reports via email, text, or other means. 6.95 08/08/2025 1. Optimized for iOS 18.
2. Updated help 6.91 05/20/2025 1. Recompiled for iOS 17.
2. Updated help.
3. Added required user-facing purpose string 6.52 01/16/2024 1. Updated help and images 6.3 02/17/2023 1. Updated help
2. Works on iOS 16 6.1 02/14/2023 Updated help 6.0 11/23/2021 Small UI update 5.9 11/21/2021 1. Optimized for iOS 15
2. Fixed issue with duct shape selector control text being cutoff
3. Updated help 5.8 10/07/2021 1. Updated the app launch screen per new Apple iOS guidelines.
2. Updated the help. 5.6 07/21/2020 1. Fixed issue with not displaying properly in iOS 13 "dark mode" 5.2 11/05/2019 1. Updated user interface for iOS 13 and iPhone 11
2. Updated help 5.0 09/26/2019 1. Works with super retina display (iPhone X screen and larger iPhones)
2. Updated help 4.7 09/20/2018 1. Optimized for iOS 11
2. Optimized for all iPhone and iPad screen sizes including the new iPhone X.
3. Updated help 4.0 12/11/2017 1. Updated the HVAC Equipment Locator module to fix issues that occur in iOS 9 3.3 11/16/2015 1. Optimized for iOS 9

2. Fixed bug where Settings form crashes in iOS 9

3. Includes updated HVAC Equipment Locator app 3.2 09/29/2015 1. Added HVAC Equipment Locator module 2.8 03/27/2015 1. Fixed scrolling issue that occurs in iPad version, landscape view 2.4 12/04/2014 1. Fixed UI bugs that occur on iOS 8 2.3 10/04/2014 1. Optimized for iOS 8
2. Fixed numerical formatting bugs due to iOS 8 2.21 09/30/2014 1. Fixed issue with screen not scrolling back after keyboard displays

2. Includes startup images 2.1 08/07/2014