Comparison

DuctChecker vs THERble

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

Head to head
About

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.

Highlights
  • Constant pressure method calculation
  • Static pressure regain method
  • Total pressure method
  • Velocity method
  • Duct dimension determination
  • Simplified duct design
Features
Read full description

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.

About

THERble

Features
Read full description

オフィス執務者の快適性や、工場の作業者や屋外環境での人の温熱感を評価する温熱指標を、測定機器や気象データなどの物性値から計算し、評価することができます。また、計算結果を、アプリ内のボタンより、画像として保存することができます。 アプリの使い方でわからないことがあった際には、アプリ内コンテンツのHelpページを参照してください。

Screenshots

DuctChecker3 screens
THERble4 screens

Verdict

The call

The clearest difference is price: THERble at Free against DuctChecker's $6.99. THERble also leads on iOS requirement (12.0 vs 15.0). DuctChecker's advantage is update cadence (every 4 months vs every 16 months). On ads, in-app purchases 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

THERble is free to download; DuctChecker costs $6.99 up front. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

DuctChecker ships an update every 4 months, THERble every 16 months. The most recent releases landed on September 7, 2026 and December 12, 2025 respectively.

Scorecard3 real differences · 5 level
DuctChecker versus THERble: the parameters behind the verdict, then further details
ParameterDuctCheckerTHERble
Price$6.99Free — better
Positive reviews0.0% of reviews—
Update frequencyEvery 4 months — betterEvery 16 months
AdsNoNo
In-app purchasesNoNo
MonetizationPaid—
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS15.012.0 — better
Further details — not scored
Size23 MB46 MB
Age rating4+17+
DeveloperAIR DESIGN, INC.SHIN NIPPON AIR TECHNOLOGIES CO.,LTD.

In-app purchases

None

DuctChecker

No in-app purchases

None

THERble

No in-app purchases

Questions

Is DuctChecker free?
DuctChecker costs $6.99, with no in-app purchases.
Is THERble free?
THERble is free to download, with no in-app purchases.
Do DuctChecker or THERble have ads?
Neither DuctChecker nor THERble shows ads.
Which is updated more often, DuctChecker or THERble?
DuctChecker ships an update every 4 months, and THERble every 16 months. Most recently, DuctChecker was updated on September 7, 2026 and THERble on December 12, 2025.

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