Comparison

HVAC Duct Sizer vs Bluon HVAC

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

Bluon HVAC

Access a vast database of HVAC-R and plumbing unit documentation, including specs, manuals, and replacement parts. Get AI-powered troubleshooting and connect with live veteran technicians for support.

Highlights
  • 35,000,000+ HVAC unit database
  • Model specs, age, and warranty info
  • Original parts and replacement options
  • AI-powered troubleshooting (Master Mechanic)
  • Live veteran technician support line
  • Supplier contact and ordering
Features
Read full description

Bluon provides the technical information and support to tackle any job in HVAC-R and plumbing. Scan or search for any unit to find the documentation on over 35,000,000+ HVAC models across virtual every brand. Instantly access the key model specs, age/warranty, manuals, original parts, part specs, and replacement options. See which suppliers carry which part - you can even text/email them or order directly through their website. Get detailed troubleshooting guidance from MasterMechanic, our custom A.l. built with the database and with the problem/solution knowledge of over 135,000 live support calls, or call our Live Tech Support line to connect to our team of 25+ year veteran technicians. Bluon has your back. App Features Include: - Database of 35,000,000+ HVAC units (manuals, specs and part lists) - Master Mechanic: leading A.I. tool for techs - Live Support line: talk to REAL veteran techs to solve problems in the field!

Screenshots

HVAC Duct Sizer4 screens
Bluon HVAC4 screens

Verdict

The call

The clearest difference is price: Bluon HVAC at Free against HVAC Duct Sizer's $4.99. Bluon HVAC also leads on rating (4.8 vs 3.1) and in-app purchases (none vs 1). HVAC Duct Sizer's advantage is ads (none vs shown). On review sentiment and device support 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

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

ReceptionRating · Positive reviews · Number of ratings

Bluon HVAC holds the better App Store score, 4.8 against 3.1. That said, the two scores are not equally well evidenced: Bluon HVAC has 4.5K 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 55% of Bluon HVAC'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, Bluon HVAC monthly. The most recent releases landed on October 31, 2026 and November 6, 2026 respectively.

Scorecard8 real differences · 2 level
HVAC Duct Sizer versus Bluon HVAC: the parameters behind the verdict, then further details
ParameterHVAC Duct SizerBluon HVAC
Price$4.99Free — better
Rating3.1 (9 ratings)4.8 (4.5K ratings) — better
Positive reviews62.5% of reviews — better54.6% of reviews
Number of ratings94.5K — better
Update frequencyEvery 3 monthsMonthly — better
AdsNo — betterYes
In-app purchasesYesNo — better
MonetizationFree with in-app purchasesAd-supported — better
DevicesiPhone, iPadiPhone, iPad, iPod — better
Requires iOS17.015.1 — better
Further details — not scored
Size1 MB170 MB
Age rating+44+
DeveloperCarmel Software CorporationBluon, Inc.

Customer experience

HVAC Duct Sizer

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

Bluon HVAC

All ratings4,453 ratings
Positive94.4%
Neutral1.6%
Negative4.0%
Written reviews141 reviews
Positive54.6%
Neutral6.4%
Negative39.0%

Bugs and requests

HVAC Duct Sizer

Not enough reviews yet to summarise bugs or requests.

Bluon HVAC

Reported bugs

2 issues
  • Login/password reset issues
  • Frequent crashes or loading problems

Requested features

3 requests
  • Individual technician subscription option
  • More comprehensive coverage of HVAC equipment models
  • Ability to access full manuals without restrictions

In-app purchases

1 purchases

HVAC Duct Sizer

One-time1
  • HVAC Equipment Locator$9.99
None

Bluon HVAC

No in-app purchases

Questions

Is HVAC Duct Sizer free?
HVAC Duct Sizer costs $4.99, and also offers in-app purchases.
Is Bluon HVAC free?
Bluon HVAC is free to download, with no in-app purchases.
Which has better reviews, HVAC Duct Sizer or Bluon HVAC?
Bluon HVAC is rated higher. HVAC Duct Sizer averages 3.1 out of 5 from 9 ratings, while Bluon HVAC averages 4.8 from 4.5K ratings.
Do HVAC Duct Sizer or Bluon HVAC have ads?
Bluon HVAC shows ads; HVAC Duct Sizer does not.
Which is updated more often, HVAC Duct Sizer or Bluon HVAC?
HVAC Duct Sizer ships an update every 3 months, and Bluon HVAC monthly. Most recently, HVAC Duct Sizer was updated on October 31, 2026 and Bluon HVAC on November 6, 2026.

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