Comparison

HVAC Pipe Sizer vs Ductulator

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

Calculate gas piping systems for low and high pressure. Input flow, pressure, or diameter to find pipe sizes, velocity, and equivalent lengths. Supports English and metric units, with extensive pipe fitting data.

Highlights
  • Low and high pressure gas pipe sizing
  • Calculate flow, pressure drop, diameter, and velocity
  • Universal app for iPhone and iPad
  • English and metric unit support
  • Built-in pipe fitting equivalent length tables
  • Slider controls for quick adjustments
Features
Read full description

The "HVAC Pipe Sizer - Gas Plus" application allows you to quickly size a simple low (less than or equal to 1.5 psi) and/or high (greater than 1.5 psi) pressure gas piping system by inputting a number of piping and gas properties. This application combines the functionality of our popular "HVAC Pipe Sizer - Gas Low" and "HVAC Pipe Sizer - Gas High" applications. This app is a universal app meaning that it works on both the iPhone and iPad and adjusts its screen size accordingly. For low pressure gas piping, you can specify the total gas flow in ft3/hr (m3/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. For high pressure gas piping, you can specify the total gas flow in ft3/hr (m3/hr), the upstream pressure (psig or kPa), and one of either downstream pressure (psig or kPa), 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, the upstream pressure, and one of either downstream pressure 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. This 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. This app now includes the HVAC Equipment Locator. Click here for details: http://bit.ly/1yTq539 The "HVAC Pipe Sizer - Gas 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

Ductulator

Instantly calculate HVAC duct sizes based on airflow, friction rate, or velocity. This tool provides accurate duct dimensions in seconds without needing charts, supporting various duct types and units.

Highlights
  • Instant duct sizing
  • Friction rate or velocity calculation
  • Multiple valid duct dimensions
  • IP and SI units support
  • Detailed sizing mode
  • Rectangular, circular, and flexible ducts
Features
Currently charting
Read full description

Size HVAC ducts instantly using airflow, friction or velocity. Get accurate duct dimensions in seconds — no charts required. • Get a range of suitable duct sizes based on friction rate or velocity. • Get multiple valid duct dimensions instantly. • Tap on Friction Rate or Velocity to toggle between calculation methods. • IP and SI units. • Detailed sizing mode to adjust the duct dimensions and air flow rates. • Supports rectangular, circular and flexible ducts. • Automatic friction and velocity updates. Calculations are based on standard air 0.075 lb/ft3 (1.2 kg/m3) in clean galvanized steel or non-metallic flexible ducts. Any feedback is welcome, and will be the basis for future updates.

Screenshots

HVAC Pipe Sizer4 screens
Ductulator4 screens

Verdict

The call

The clearest difference is in-app purchases: Ductulator at none against HVAC Pipe Sizer's 1. Ductulator also leads on ratings volume (353 vs 1) and update cadence (every 2 months vs every 10 months). HVAC Pipe Sizer's advantage is review sentiment (80% vs 50%) and rating (5.0 vs 4.7). 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

HVAC Pipe Sizer costs $7.99 and Ductulator $3.99 up front. HVAC Pipe Sizer sells 1 one-off in-app purchase. Ductulator asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

HVAC Pipe Sizer holds the better App Store score, 5.0 against 4.7. That said, the two scores are not equally well evidenced: Ductulator has 353 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 80% of HVAC Pipe Sizer's written reviews are positive against 50% of Ductulator's.

UpkeepUpdate frequency

HVAC Pipe Sizer ships an update every 10 months, Ductulator every 2 months. The most recent releases landed on October 24, 2026 and October 25, 2026 respectively.

Scorecard8 real differences · 3 level
HVAC Pipe Sizer versus Ductulator: the parameters behind the verdict, then further details
ParameterHVAC Pipe SizerDuctulator
Price$7.99$3.99 — better
Rating5.0 (1 ratings) — better4.7 (353 ratings)
Positive reviews80.0% of reviews — better50.0% of reviews
Number of ratings1353 — better
Update frequencyEvery 10 monthsEvery 2 months — better
AdsNoNo
In-app purchasesYesNo — better
MonetizationPaidFree — better
Best chart rank—#83 — better
DevicesiPhone, iPadiPhone, iPad
Requires iOS17.0 — better18.6
Further details — not scored
Size1 MB1 MB
Age rating4+4+
DeveloperCarmel Software CorporationWassim Murr

Customer experience

HVAC Pipe Sizer

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews5 reviews
Positive80.0%
Neutral0.0%
Negative20.0%

Ductulator

All ratings317 ratings
Positive93.4%
Neutral2.2%
Negative4.4%
Written reviews22 reviews
Positive50.0%
Neutral13.6%
Negative36.4%

Bugs and requests

HVAC Pipe Sizer

Not enough reviews yet to summarise bugs or requests.

Ductulator

Reported bugs

4 issues
  • Decimal point doesn't work on calculator
  • New flex option isn't working properly
  • Friction rate can't be changed in the latest version
  • Skips duct sizes (e.g., 24-26)

Requested features

5 requests
  • Ability to pick duct size and see CFM
  • Include flat oval ducts
  • Option to select round or square duct
  • Ability to enter duct size and get CFM
  • Option for flex duct

In-app purchases

1 purchases

HVAC Pipe Sizer

One-time1
  • HVAC Equipment Locator$9.99
None

Ductulator

No in-app purchases

Questions

Is HVAC Pipe Sizer free?
HVAC Pipe Sizer costs $7.99, and also offers in-app purchases.
Is Ductulator free?
Ductulator costs $3.99, with no in-app purchases.
Which has better reviews, HVAC Pipe Sizer or Ductulator?
HVAC Pipe Sizer is rated higher. HVAC Pipe Sizer averages 5.0 out of 5 from 1 ratings, while Ductulator averages 4.7 from 353 ratings.
Do HVAC Pipe Sizer or Ductulator have ads?
Neither HVAC Pipe Sizer nor Ductulator shows ads.
Which is updated more often, HVAC Pipe Sizer or Ductulator?
HVAC Pipe Sizer ships an update every 10 months, and Ductulator every 2 months. Most recently, HVAC Pipe Sizer was updated on October 24, 2026 and Ductulator on October 25, 2026.

Other comparisons