Comparison

HVAC Pipe Sizer Plus vs Duct Calculator

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

Head to head
About

HVAC Pipe Sizer Plus

This utility app combines three specialized pipe sizing tools for HVAC systems: liquid, steam, and gas. It offers flexible input options, unit conversions, and an equipment locator for comprehensive HVAC design.

Highlights
  • Liquid pipe sizing
  • Steam pipe sizing with steam table calculator
  • Gas pipe sizing (low and high pressure)
  • HVAC Equipment Locator
  • Slider controls for input adjustments
  • English and Metric unit display
Features
Read full description

The HVAC Pipe Sizer Plus application is a combination of three (3) of our individual pipe sizing applications including: 1. HVAC Pipe Sizer - Liquid 2. HVAC Pipe Sizer - Steam 3. HVAC Pipe Sizer - Gas Plus This app is a universal app that works on both the iPhone and iPad and adjusts its screen size accordingly. The "HVAC Pipe Sizer - Gas" module allows you to quickly size a simple low (less than or equal to 1.5 psi) and high (greater than 1.5 psi) pressure gas piping system by inputting a number of piping and gas properties. The "HVAC Pipe Sizer - Steam" module allows you to size a steam pipe run, and it also includes a bonus steam table calculator. The "HVAC Pipe Sizer - Liquid" module allows you to size a pipe run with many different types of liquids (or fluids), pipe material and fitting types. This application includes all of the great features of the individual pipe sizer apps such as the use of slider controls that allow you to quickly increment or decrement the input values and immediately observe the calculated results. It also allows you to specify different types of liquids, gases, pipe material types, fitting quantities, min and max ranges, and step values. Also, you can display a wide variety of English and Metric units. The "HVAC Pipe Sizer Plus" 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

Duct Calculator

This app allows HVAC professionals to quickly and accurately size new ducts or calculate the performance of existing ones. It supports both round and rectangular ductwork, offering precise calculations through direct entry or intuitive sliders. The tool provides live updates and outputs key performance metrics.

Highlights
  • Size round and rectangular ductwork
  • Adjust airflow, diameter, width, and height
  • Direct number entry for precision
  • Lockable dimensions for 'what-if' scenarios
  • Live update of calculated values
  • Outputs velocity and pressure drop
  • Supports IP and SI units
Features
Read full description

The Duct Calculator App for iPhone/iPad is a modern take on a the classic duct sizing wheel, allowing HVAC engineers, designers and contractors quickly and accurately size a new duct or calculate the performance of an existing duct on your iOS devices. Size both round and rectangular ductwork with the ease of a traditional Ductulator. Adjust the airflow, diameter, width or height sliders with your thumbs. Get maximum precision by entering numbers directly into the the calculator. Lock friction rate, diameter or width or height to make the calculations you need for your design. Live update of the calculated values allows you to see the impact of the changes immediately. Outputs velocity for both round and rectangular ducts. PERFORM QUICK AND ACCURATE CALCULATIONS: Enter the airflow and sizes in directly as numbers for maximum precision. - or - Use the airflow and size sliders for quick calculations. Shows live equivalent round/rectangular duct sizes. Specific dimensions can be locked to allow specific what-ifs to be quickly calculated. Works for both IP and SI units. You can select from a range of duct roughness categories. Designed to allow quick calculations anywhere, anytime, it is ideal for the HVAC designer or contractor. HOW TO USE: Locking Dimensions: The lock symbols to the right of the duct dimensions indicate if that particular dimension is locked when calculating new equivalent values when a dimension is updated. The Diameter can be locked or unlocked. The Width or Height can be locked, but not both. Using the Sliders: Move the sliders for Airflow, Duct Diameter, Width and Height up and down to match the desired duct size to calculate velocity and pressure drop for. The Diameter, Width and Height will change such that the equivalent size is shown: Changing the diameter will updated either the equivalent Width or the Height, depending on which dimension is unlocked. Changing the Width or Height will update the equivalent Diameter if it is unlocked, or the other rectangular duct dimension of the Diameter size is locked. Direct Entry: The values for Airflow, Diameter, Width and Height can be directly edited in the text boxes to allow quick entry of exact numbers. Invalid entries will generate an error message, and must be corrected prior to the calculations updating. Output: The values for the calculated Velocity for Round Duct and Rectangular Duct are shown, as is the Pressure Drop per Length value. NOTES: This application (App) is provided for use by qualified HVAC engineers and designers in the design of air handling systems and is not a substitute for appropriate design services. When in doubt, contact a design professional.

Screenshots

HVAC Pipe Sizer Plus4 screens
Duct Calculator4 screens

Verdict

The call

The clearest difference is rating: Duct Calculator at 4.5 against HVAC Pipe Sizer Plus's 3.0. Duct Calculator also leads on update cadence (every 2 months vs every 15 months) and ratings volume (189 vs 1). HVAC Pipe Sizer Plus's advantage is price ($13.99 vs $19.99) and review sentiment (67% vs 57%). On ads and in-app purchases 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

HVAC Pipe Sizer Plus costs $13.99 and Duct Calculator $19.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

Duct Calculator holds the better App Store score, 4.5 against 3.0. That said, the two scores are not equally well evidenced: Duct Calculator has 189 ratings behind it against 1, so its average is the more settled of the two. Written reviews complicate that: 67% of HVAC Pipe Sizer Plus's written reviews are positive against 57% of Duct Calculator's, so the app with the better star average is not the one people write more warmly about.

UpkeepUpdate frequency

HVAC Pipe Sizer Plus ships an update every 15 months, Duct Calculator every 2 months. The most recent releases landed on October 27, 2026 and October 22, 2026 respectively.

Scorecard8 real differences · 2 level
HVAC Pipe Sizer Plus versus Duct Calculator: the parameters behind the verdict, then further details
ParameterHVAC Pipe Sizer PlusDuct Calculator
Price$13.99 — better$19.99
Rating3.0 (1 ratings)4.5 (189 ratings) — better
Positive reviews66.7% of reviews — better57.1% of reviews
Number of ratings1189 — better
Update frequencyEvery 15 monthsEvery 2 months — better
AdsNoNo
In-app purchasesNoNo
MonetizationPaidFree — better
DevicesiPhone, iPadiPhone, iPad, iPod, Mac — better
Requires iOS17.015.0 — better
Further details — not scored
Size2 MB2 MB
Age rating+44+
DeveloperCarmel Software CorporationPheinex, LLC

Customer experience

HVAC Pipe Sizer Plus

All ratings1 ratings
Positive0.0%
Neutral100.0%
Negative0.0%
Written reviews3 reviews
Positive66.7%
Neutral33.3%
Negative0.0%

Duct Calculator

All ratings189 ratings
Positive88.4%
Neutral3.7%
Negative7.9%
Written reviews21 reviews
Positive57.1%
Neutral14.3%
Negative28.6%

In-app purchases

None

HVAC Pipe Sizer Plus

No in-app purchases

None

Duct Calculator

No in-app purchases

Questions

Is HVAC Pipe Sizer Plus free?
HVAC Pipe Sizer Plus costs $13.99, with no in-app purchases.
Is Duct Calculator free?
Duct Calculator costs $19.99, with no in-app purchases.
Which has better reviews, HVAC Pipe Sizer Plus or Duct Calculator?
Duct Calculator is rated higher. HVAC Pipe Sizer Plus averages 3.0 out of 5 from 1 ratings, while Duct Calculator averages 4.5 from 189 ratings.
Do HVAC Pipe Sizer Plus or Duct Calculator have ads?
Neither HVAC Pipe Sizer Plus nor Duct Calculator shows ads.
Which is updated more often, HVAC Pipe Sizer Plus or Duct Calculator?
HVAC Pipe Sizer Plus ships an update every 15 months, and Duct Calculator every 2 months. Most recently, HVAC Pipe Sizer Plus was updated on October 27, 2026 and Duct Calculator on October 22, 2026.

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