Comparison

HVAC Toolkit vs Duct Construction

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

Head to head
About

HVAC Toolkit

This comprehensive toolkit offers essential HVAC calculations and tools for professionals. It combines multiple specialized applications into a single, convenient package for iPhone and iPad users.

Highlights
  • Equipment tracking and customization
  • Refrigerant pressure-temperature charts
  • Refrigerant charge calculations
  • Duct sizing
  • Cooling and heating load calculations
  • Psychrometric calculations
  • Steam tables
  • Pipe sizing for liquid, steam, and gas
Features
Read full description

The HVAC Toolkit app for the iPhone and iPad is the essential app for anyone in the HVAC industry. It includes a combination of many of our stand-alone iOS applications. Individually, the apps cost a total of $70. By purchasing the Toolkit, you pay only $24: 1. HVAC Equipment Locator 2. HVAC PT Chart 3. HVAC Refrigerant Charge 4. HVAC Duct Sizer 5. HVAC Quick Load 6. Psychrometrics 7. Steam Tables 8. Pipe Sizer - Liquid 9. Pipe Sizer - Steam 10. Pipe Sizer - Gas High 11. Pipe Sizer - Gas Low This is a universal app that works on both the iPhone and iPad. The "HVAC Equipment Locator" module allows you to track, share, and customize your equipment nameplate and maintenance data. The version here includes the ability to customize your input screens. The "HVAC PT Chart" module allows you to easily view the pressure-temperature properties of 75 refrigerants. Think of this app as a digital version of the paper PT charts that you may have carried around with you in the past. The "HVAC Refrigerant Charge" module allows you to perform superheat and subcool refrigerant charge calculations on-the-fly. This app includes pressure-temperature data for over 75 common refrigerants. The "HVAC Duct Sizer" module allows you to quickly size one HVAC duct run and a range of duct sizes. 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 "HVAC Quick Load" module allows you to perform quick and simple HVAC cooling and heating load calculation analysis. You can specify the building type, total area, and # of people. The results include the total cooling and heating loads and airflows. The "Psychrometrics" module allows you to easily perform single-state and mixed-air HVAC psychrometric calculations for a wide range of barometric air pressures. The "Steam Tables" module allows you to calculate the properties of saturated or superheated steam by specifying 2 input properties. 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. 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 - Gas High/Low" 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. This application includes all of the great features of the individual HVAC iOS applications 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. All of the above modules display units in English or Metric. Also, all of the above modules allow you to send emails with inputs and results. The "HVAC Toolkit" 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, Carmel has developed customized apps for organizations such as ASHRAE, Mitsubishi Electric, and Pacific Gas and Electric, amongst others. We also offer all of the above modules as individual apps for the iPhone/iPad: 1. HVAC ResLoad-J 2. HVAC Psych HD 3. HVAC Duct Sizer 4. HVAC Pipe Sizers 5. Steam Tables 6. Psychrometric Plus 7. Psychrometric LT 8. HVAC Pipe Sizer Plus 9. HVAC Pipe Sizer Gas Plus 10. HVAC Quick Load 11. HVAC Load Plus 12. HVAC Residential Load Calcs 13. HVAC Toolkit Ultimate 14. HVAC ASHRAE 62.1 15. HVAC ResVent 62.2 16. HVAC ASHRAE DFDB 17. HVAC ASHRAE Psych Chart

About

Duct Construction

This app helps determine duct construction and reinforcement options based on duct size and system pressure class. It provides condensed lists of suitable options, saving time spent on manual calculations and table lookups. Results are based on industry standards for galvanized steel duct sheets.

Highlights
  • Duct size range from 2" to 120"
  • Pressure classes up to 4 in.wg
  • Calculates duct weights per linear foot
  • Determines required duct gauge and reinforcement spacing
  • Clear illustrations for reinforcement types
  • Simple and effective UI design
Features
Read full description

Get all duct construction and reinforcement options by entering the duct size and system pressure class. The aim of the app is to save time spent browsing through tables and texts to determine suitable options, by relying on the most widely used standards and providing a condensed list of available duct construction options. The results are based on galvanized steel duct sheets conforming to ASTM A653 & A924. The app does not cover all aspects of duct construction, as it is intended as a guide; Reliance on related standards, as well as good engineering sense is the basis for proper design. Features: 1. Duct sizes from 2" to 120" 2. Pressure classes 0.5 in.wg, 1 in.wg, 2 in.wg, 3 in.wg and 4 in.wg. 3. Provides the duct weights for each option per linear foot. 4. Provides required duct gauge and reinforcement spacing. 5. Clear illustration for each reinforcement type, as well as dimensions. 6. Simple and effective UI design. Roadmap / Upcoming updates: 1. SI units. 2. More pressure class options. 3. User will be able to save and retreive duct data for future reference. 3. More Reinforcement options, including tie-rodding. Request a feature: welmurr@icloud.com

Screenshots

HVAC Toolkit4 screens
Duct Construction4 screens

Verdict

The call

The clearest difference is review sentiment: HVAC Toolkit at 73% against Duct Construction's 0%. HVAC Toolkit also leads on rating (5.0 vs 1.0) and iOS requirement (13.0 vs 17.6). Duct Construction's advantage is price ($0.99 vs $23.99) and chart position (#106 vs unranked). On ratings volume, update cadence, 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 Toolkit costs $23.99 and Duct Construction $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

HVAC Toolkit holds the better App Store score, 5.0 against 1.0. Both are backed by a comparable volume of ratings — 2 and 1 respectively. Written reviews point the same way: 73% of HVAC Toolkit's written reviews are positive against 0% of Duct Construction's.

UpkeepUpdate frequency

HVAC Toolkit ships an update every 6 months, Duct Construction every 10 months. The most recent releases landed on September 14, 2026 and September 25, 2026 respectively.

Scorecard5 real differences · 6 level
HVAC Toolkit versus Duct Construction: the parameters behind the verdict, then further details
ParameterHVAC ToolkitDuct Construction
Price$23.99$0.99 — better
Rating5.0 (2 ratings) — better1.0 (1 ratings)
Positive reviews73.3% of reviews — better0.0% of reviews
Number of ratings2 — better1
Update frequencyEvery 6 months — betterEvery 10 months
AdsNoNo
In-app purchasesNoNo
MonetizationPaidPaid
Best chart rank—#106 — better
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS13.0 — better17.6
Further details — not scored
Size50 MB1 MB
Age rating4+4+
DeveloperCarmel Software CorporationWassim Murr

Customer experience

HVAC Toolkit

All ratings2 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews15 reviews
Positive73.3%
Neutral0.0%
Negative26.7%

Duct Construction

All ratings1 ratings
Positive0.0%
Neutral0.0%
Negative100.0%
Written reviews3 reviews
Positive0.0%
Neutral0.0%
Negative100.0%

In-app purchases

None

HVAC Toolkit

No in-app purchases

None

Duct Construction

No in-app purchases

Questions

Is HVAC Toolkit free?
HVAC Toolkit costs $23.99, with no in-app purchases.
Is Duct Construction free?
Duct Construction costs $0.99, with no in-app purchases.
Which has better reviews, HVAC Toolkit or Duct Construction?
HVAC Toolkit is rated higher. HVAC Toolkit averages 5.0 out of 5 from 2 ratings, while Duct Construction averages 1.0 from 1 ratings.
Do HVAC Toolkit or Duct Construction have ads?
Neither HVAC Toolkit nor Duct Construction shows ads.
Which is updated more often, HVAC Toolkit or Duct Construction?
HVAC Toolkit ships an update every 6 months, and Duct Construction every 10 months. Most recently, HVAC Toolkit was updated on September 14, 2026 and Duct Construction on September 25, 2026.

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