DuctChecker vs SetsubiWorks HVAC Sizing Calc
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
DuctChecker
Easily calculate duct dimensions using various engineering methods like constant pressure, static pressure regain, total pressure, and velocity. This tool simplifies complex duct design calculations, typically found in flow diagrams or slide rules.
- Constant pressure method calculation
- Static pressure regain method
- Total pressure method
- Velocity method
- Duct dimension determination
- Simplified duct design
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To determine the size of the duct constant pressure method, static pressure regain method, total pressure method, velocity method. Generally uses constant pressure method. This constant pressure method is how to determine the duct dimensions using the same value per 1 m on all duct friction loss. Usually determined by flow diagrams or duct design for slide rules. You can easily determine the duct by using this program.
SetsubiWorks HVAC Sizing Calc
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No more squinting at a calculator on site. SetsubiWorks puts eleven calculations that HVAC and plumbing engineers reach for every day - design, site supervision, cost estimation - into a single app on your phone. The calculation logic is a native iOS port of an internal Django tool that has been used on real projects. WHAT IT DOES - Unit Conversion - primary energy conversion for electricity, city gas and COP - Air State Calculation - moist air properties from dry-bulb temperature and any humidity index (relative humidity, wet-bulb, dew point, absolute humidity) - AHU Psychrometric Chart - cooling and heating processes, capacity and water flow, with a natively drawn psychrometric chart - Air Conditioning Equipment Calculations - supply airflow, sensible heat load, coil water flow and required humidification - Duct Size Selection - spiral and rectangular duct sizes from airflow - Louver / Grille Size Selection - louver and grille sizes from airflow - Smoke Exhaust Fan Selection - smoke exhaust airflow for smoke compartments, vestibules and elevator lobbies from the smoke exhaust area - Water Supply Pipe Selection - nominal pipe size from flow rate - Drainage Pipe Size Selection - drainage pipe sizing using the Manning and Kutter formulas - Rainwater Pipe - rainwater leader and horizontal pipe sizes from roof and wall areas - Equipment Combined Noise Calculation - combines the SPL of multiple units with distance attenuation BUILT-IN CALCULATOR ON IPAD On iPad, Duct Size Selection and Louver / Grille Size Selection come with a calculator panel. Enter several airflows as a formula, such as 1200+800+650x2, and the app adds them up and goes straight to sizing. With the calculator on the left and the results on the right, the large screen makes design reviews and drawing checks faster. WHO IT IS FOR A quick check on site, a rough figure during a meeting, some groundwork before an estimate - the moments where opening a laptop is overkill but a pocket calculator is tedious. Useful for design engineers, site supervisors and estimators, and for students checking their own answers while studying for professional qualifications. PRICING All features are free for 14 days after installation. After that, a single one-time purchase keeps every feature unlocked. There is no subscription and no monthly fee. DETAILS - Requires iOS 16.0 or later - No network communication, no data collection. Every calculation runs on your device - Available in Japanese, English, Simplified Chinese and Vietnamese - Results are reference values. Always have a qualified engineer verify them before applying them to actual design or construction Feedback and bug reports are welcome from the in-app settings screen or via the support link below.
Screenshots
Verdict
The clearest difference is price: SetsubiWorks HVAC Sizing Calc at Free against DuctChecker's $6.99. SetsubiWorks HVAC Sizing Calc also leads on update cadence (weekly vs every 4 months). DuctChecker's advantage is in-app purchases (none vs 2) and iOS requirement (15.0 vs 17.0). On ads 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
SetsubiWorks HVAC Sizing Calc is free to download; DuctChecker costs $6.99 up front. SetsubiWorks HVAC Sizing Calc sells 2 one-off in-app purchases. DuctChecker asks for nothing beyond the download.
DuctChecker ships an update every 4 months, SetsubiWorks HVAC Sizing Calc weekly. The most recent releases landed on October 29, 2026 and October 26, 2026 respectively.
| Parameter | DuctChecker | SetsubiWorks HVAC Sizing Calc |
|---|---|---|
| Price | $6.99 | Free — better |
| Positive reviews | 0.0% of reviews | — |
| Update frequency | Every 4 months | Weekly — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Paid | — |
| Devices | iPhone, iPad, iPod — better | iPhone, iPad |
| Requires iOS | 15.0 — better | 17.0 |
| Further details — not scored | ||
| Size | 23 MB | 2 MB |
| Age rating | 4+ | 4+ |
| Developer | AIR DESIGN, INC. | MASAYOSHI SUGIMOTO |
In-app purchases
DuctChecker
No in-app purchases
SetsubiWorks HVAC Sizing Calc
- 14-day TrialFree
- 設備Works 製品版$4.99
Questions
Is DuctChecker free?
Is SetsubiWorks HVAC Sizing Calc free?
Do DuctChecker or SetsubiWorks HVAC Sizing Calc have ads?
Which is updated more often, DuctChecker or SetsubiWorks HVAC Sizing Calc?
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