Comparison

HVAC Duct Sizer vs Ruud

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

HVAC Duct Sizer

This app provides quick and simple HVAC duct sizing analysis. It allows users to calculate duct dimensions based on airflow or existing dimensions, and can also determine a range of duct sizes. Results can be emailed for further analysis.

Highlights
  • Duct sizing by airflow
  • Duct sizing by dimensions
  • Range of duct sizes calculation
  • Rectangular, round, and oval duct shapes
  • English and Metric unit options
  • Email results with CSV attachment
  • HVAC Equipment Locator
Features
Read full description

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

About

Ruud

This app streamlines HVAC installation, service, and support for contractors. It offers Bluetooth connectivity for system setup and troubleshooting, along with access to product information, warranty tracking, and dealer locators.

Highlights
  • Bluetooth setup and troubleshooting
  • System operating parameter monitoring
  • Alarm diagnosis and history
  • Access installation instructions and manuals
  • Track warranty information
  • Locate retailers and distributors
  • Find rebate and financing information
Features
Read full description

We’ve redesigned Ruud for Contractors to offer the industry’s most powerful, intuitive, and easy-to-use app. Whether you’re on a residential service call or installing 40 units at a major site, the free Ruud Contractor app’s Bluetooth® capability – paired with an enabled HVAC system -- makes set-up and troubleshooting simpler than ever. With Ruud for Contractors and eligible air systems, you can easily: Install - Set up systems quickly and easily with the new Bluetooth® setup - Monitor operating parameters from your phone while charging outdoor units - Verify system setup with access to system operating status - Quickly check for alarms Service - Diagnose active alarms and alarm history - Check system operating status - Easy step-by-step parts replacement and system setup The Ruud for Contractors app also offers powerful support for all of our air and water products, with a new Product Technical Support design that is easier to use and more accurate than ever: - Access installation instructions - Search parts lists - Download manuals - View tech sheets - Research consumer literature Track Warranty information - Scan and confirm model and ownership details - Check warranty status and share HVAC systems warranty certificate Locate - Look up retailers - Look up distributors Research - Find up-to-date rebate information - Research financing options - Offer extended warranty - Confirm AHRI information and certification for HVAC systems

Screenshots

HVAC Duct Sizer4 screens
Ruud4 screens

Verdict

The call

The clearest difference is price: Ruud at Free against HVAC Duct Sizer's $4.99. Ruud also leads on rating (4.6 vs 3.1) and in-app purchases (none vs 1). HVAC Duct Sizer's advantage is review sentiment (63% vs 50%). On ads, device support and iOS requirement there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Ruud is free to download; HVAC Duct Sizer costs $4.99 up front. HVAC Duct Sizer sells 1 one-off in-app purchase. Ruud asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

Ruud holds the better App Store score, 4.6 against 3.1. That said, the two scores are not equally well evidenced: Ruud has 1.1K ratings behind it against 9, so its average is the more settled of the two. Written reviews complicate that: 63% of HVAC Duct Sizer's written reviews are positive against 50% of Ruud's, so the app with the better star average is not the one people write more warmly about.

UpkeepUpdate frequency

HVAC Duct Sizer ships an update every 3 months, Ruud monthly. The most recent releases landed on October 27, 2026 and October 28, 2026 respectively.

Scorecard7 real differences · 3 level
HVAC Duct Sizer versus Ruud: the parameters behind the verdict, then further details
ParameterHVAC Duct SizerRuud
Price$4.99Free — better
Rating3.1 (9 ratings)4.6 (1.1K ratings) — better
Positive reviews62.5% of reviews — better50.0% of reviews
Number of ratings91.1K — better
Update frequencyEvery 3 monthsMonthly — better
AdsNoNo
In-app purchasesYesNo — better
MonetizationFree with in-app purchasesFree — better
DevicesiPhone, iPad — betteriPhone
Requires iOS17.016.0 — better
Further details — not scored
Size1 MB112 MB
Age rating+44+
DeveloperCarmel Software CorporationRheem Manufacturing Company

Customer experience

HVAC Duct Sizer

All ratings9 ratings
Positive44.4%
Neutral11.1%
Negative44.4%
Written reviews40 reviews
Positive62.5%
Neutral5.0%
Negative32.5%

Ruud

All ratings1,060 ratings
Positive90.8%
Neutral2.6%
Negative6.5%
Written reviews8 reviews
Positive50.0%
Neutral12.5%
Negative37.5%

In-app purchases

1 purchases

HVAC Duct Sizer

One-time1
  • HVAC Equipment Locator$9.99
None

Ruud

No in-app purchases

Questions

Is HVAC Duct Sizer free?
HVAC Duct Sizer costs $4.99, and also offers in-app purchases.
Is Ruud free?
Ruud is free to download, with no in-app purchases.
Which has better reviews, HVAC Duct Sizer or Ruud?
Ruud is rated higher. HVAC Duct Sizer averages 3.1 out of 5 from 9 ratings, while Ruud averages 4.6 from 1.1K ratings.
Do HVAC Duct Sizer or Ruud have ads?
Neither HVAC Duct Sizer nor Ruud shows ads.
Which is updated more often, HVAC Duct Sizer or Ruud?
HVAC Duct Sizer ships an update every 3 months, and Ruud monthly. Most recently, HVAC Duct Sizer was updated on October 27, 2026 and Ruud on October 28, 2026.

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