--- schema_type: "SoftwareApplication" entity_type: "Mobile Application" app_name: "Duct Calculator." developer_entity: "Sachinbhai Surani" bundle_id: "duct.calculator" app_store_id: "6756908372" category: "Productivity" primary_platform: "ios" primary_monetization: "Freemium" offline_capable: false market_region: "US" platforms: "iOS" app_last_updated: "2025-12-24" report_date: "2026-08-24" last_verified: "2026-08-24T00:00:00.000Z" report_version: "1.0" total_reviews: 3 overall_rating: 4.7 confidence: "low" confidence_score: 0.2 data_age_days: 38 momentum_velocity: "zombie" intelligence_version: 3 tags: ["productivity", "freemium", "mobile app", "app review", "app analysis", "engineers,", "designers,", "installation"] canonical_url: "https://marlvel.ai/apps/duct-calculator" license: "CC-BY-NC 4.0" content_version: "v2" --- # Duct Calculator. Intelligence Report ## TL;DR {#tldr} - **Category**: Productivity · Freemium - **Signal**: Rating 4.67 > **TL;DR:** Duct Calculator. is a productivity app by Sachinbhai Surani, rated 4.67/5 by 3 users, available on iOS. > > **Marlvel.ai App Intelligence** - Independent analysis. US Market. No publisher influence. > **Key Insight:** Duct Calculator. is a productivity app by Sachinbhai Surani. ## Quick Facts | Fact | Value | | :--- | :--- | | **Rating** | 4.67/5 (3 reviews) | | **Category** | Productivity | | **Developer** | Sachinbhai Surani | | **Pricing** | Freemium | | **Platforms** | iOS | | **Confidence** | Low (0.2/1.0) | | **Data Age** | 38d | ## Metadata & Market Performance - **Publisher:** Sachinbhai Surani - **Category:** Productivity - **Target Audience:** HVAC engineers, designers, and installation technicians requiring on-site ventilation calculations. - **Platforms:** iOS - **Version Reviewed:** 1.0 - **Report Date:** 2026-08-24 - **Signal Count:** 0 reviews analyzed - **Confidence:** Low (0.2/1.0) - **App Store ID (iOS):** 6756908372 - **Bundle ID:** duct.calculator - **Performance Trend:** Stable - **Data Window:** Analysis based on signals collected up to 2026-08-24 ## Executive Snapshot **What it is:** Duct Calculator is a specialized HVAC utility for engineers and technicians to calculate duct dimensions and airflow values on iOS. **Why users hire it:** The app removes the need for manual slide rules or complex spreadsheets during on-site ventilation design and installation work. ## App DNA (Features & Intent) - **[Standard] Duct Sizing Calculator:** Calculates required duct dimensions using CFM and FPM inputs for rectangular and circular ducts, serving as a core utility for HVAC design. - **[Standard] Airflow Verification:** Determines CFM and FPM values to verify ventilation system performance on-site. * *User Intent:* Users expect intelligent, adaptive experiences that learn from their behavior. - **[Basic] Ad Removal:** Lifetime purchase option to remove advertisements, targeting professionals seeking a permanent utility tool. * *User Intent:* Users seek enhanced value through premium features. ## Market Position {#market-position} Duct Calculator occupies a narrow productivity niche for HVAC professionals. With only three ratings recorded, the app lacks the social proof or chart velocity of broader engineering utilities. ## Monetization Strategy - **Model:** Freemium - **Tiers:** Free with ads, Lifetime purchase to remove ads - **Analysis:** The freemium model relies on a single lifetime IAP to remove ad-inventory, targeting professionals seeking a permanent utility tool. ## SWOT Analysis {#swot} **Core Strengths:** - Specialized HVAC calculation logic provides direct utility for on-site design - Dual support for rectangular and circular duct sizing covers primary standards **Growth Levers:** - Material-cost estimation integration captures workflow overlap with project bidding - Offline-first performance serves construction environments with poor connectivity ## Recent Changes (v2 → v3) {#recent-changes} The app remains in a maintenance-only state, but the competitive assessment has sharpened to identify the lack of project-save functionality as a critical barrier to professional retention. **Overall trend**: Stable **Compared at**: 2026-08-24 ### High-impact changes - **[Shifted] Prioritization of project-save functionality** (features) ### Medium-impact changes - **[Added] New SWOT entries** (swot) - **[Shifted] Competitive narrative pivot** (positioning) ## App Momentum (Zombie) {#momentum} - Quiet 8 months, no feature updates. - Last major release December 2025. > **Cadence:** 1 total versions · 0 majors in last 6 months · 242 days since last update ## The "So What?" (Strategic Takeaway) {#so-what} Duct Calculator. is a productivity app that is free with in-app purchases. It holds a 4.67/5 rating from 3 reviews. > **Bottom Line:** Duct Calculator provides a stable, specialized utility for HVAC professionals, but the lack of active development limits its long-term retention potential. **Best for:** HVAC engineers, designers, and installation technicians requiring on-site ventilation calculations. ### PM Action Plan (Next Best Moves) - [ ] [INVEST] Ship project-save functionality because it is the top friction point for on-site technicians → increase session frequency ### Outlook: Stable The HVAC utility market is consolidating around tools that integrate project management with technical calculations. Duct Calculator's current maintenance-only trajectory leaves it exposed to competitors that offer more comprehensive workflow support. - ⚪ The eight-month development gap suggests a maintenance-only posture, which limits the app's ability to capture new professional segments. ## Key Metrics Summary | Metric | Value | | :--- | :--- | | Overall Rating | 4.67/5 | | Total Reviews | 3 | | Confidence | Low | | Pricing Model | Freemium | | Platforms | iOS | | Key Features | 3 analyzed | | Trend | Stable | | Outlook | Stable | ## Competitor Comparison | App | Rating | Sentiment | Developer | | :--- | :--- | :--- | :--- | | **Duct Calculator.** (this app) | 4.67/5 | N/A | Sachinbhai Surani | | [Mitsu: AI Life Coach](https://marlvel.ai/apps/mitsu-ai-life-coach) | N/A/5 | N/A | C2 Insights | | [ChatGPT](https://marlvel.ai/apps/chatgpt) | 4.8/5 | n/a | OpenAI OpCo, LLC | | [HitWave](https://marlvel.ai/apps/ciendor-applications-hitwave) | 2.6/5 | Mixed | Ciendor Holdings Corp. LTD | | [Paper: Sketch, Draw & Create](https://marlvel.ai/apps/paper-sketch-draw-create) | 4.6/5 | N/A | Evernote Corporation | | [Pattrn - Discipline Tracker](https://marlvel.ai/apps/pattrn-discipline-tracker) | 4.8/5 | Thrilled | Pedro Schott | ## Company Profile - **Developer:** Sachinbhai Surani - **Website:** [https://semiconhub.in](https://semiconhub.in) ## Data Sources & Links - **App Store:** [View on Apple Store](https://apps.apple.com/us/app/duct-calculator/id6756908372?uo=4) - **Dev Site:** [Official Website](https://semiconhub.in) - **Sources:** Developer website content, App store metadata. ## Related Intel Reports - [*Mitsu: AI Life Coach*](https://marlvel.ai/apps/mitsu-ai-life-coach) (C2 Insights) · N/A Rating - [*ChatGPT*](https://marlvel.ai/apps/chatgpt) (OpenAI OpCo, LLC) · 4.8/5 Rating - [*HitWave*](https://marlvel.ai/apps/ciendor-applications-hitwave) (Ciendor Holdings Corp. LTD) · 2.6/5 Rating - [*Paper: Sketch, Draw & Create*](https://marlvel.ai/apps/paper-sketch-draw-create) (Evernote Corporation) · 4.6/5 Rating - [*Pattrn - Discipline Tracker*](https://marlvel.ai/apps/pattrn-discipline-tracker) (Pedro Schott) · 4.8/5 Rating | Excellent Sentiment - [*SpaceDesk App*](https://marlvel.ai/apps/spacedesk-app) (Hawsabah) · N/A Rating - [*한음달-한국인에게 꼭 맞는 음력달력, 캘린더*](https://marlvel.ai/apps/app--103) (YunaSoft Inc.) · 4.6/5 Rating - [*바로메모 - 매일 바로 작성하는 메모장*](https://marlvel.ai/apps/cswpd-memo) (SuWon Choi) · N/A Rating - [*근로장려금 알리미 - 신청, 기준, 금액계산 가이드*](https://marlvel.ai/apps/com-swing2app-v3-d83e9bb95c05347f59ad81dea3b925ebf) (SY Company) · 3.8/5 Rating - [*통화관리솔루션 (부평구청용)*](https://marlvel.ai/apps/byto-bupyeong) (BYTO) · N/A Rating ## Frequently Asked Questions {#faq} ### Is Duct Calculator suitable for professional HVAC design? Yes, Duct Calculator is designed for HVAC engineers and technicians to perform duct sizing and airflow verification on-site, supporting both rectangular and circular duct types. ### Does Duct Calculator work offline? The app is designed for on-site use, which typically requires offline functionality. However, it does not currently support cloud-sync for project saving. ### What is the difference between the free and paid versions? The free version includes advertisements, while a lifetime in-app purchase is available to remove all ads from the interface. ## Methodology {#methodology} This report was generated by Marlvel.ai's 5-stage AI intelligence pipeline: 1. **Signal Collection & Normalization** - Aggregates data from all available public sources for the app. Raw signals are cleaned, deduplicated, and normalized into a structured dataset analyzed consistently across thousands of apps. 2. **Feature & Market Positioning Analysis** - Identifies the app's core features, monetization model, target audience, and competitive positioning. Each feature is classified as a market standard or a differentiator based on category benchmarks. 3. **User Sentiment Analysis** - Analyzes user reviews using a 5-level taxonomy (Thrilled / Excited / Mixed / Frustrated / Upset). Combines star ratings and volume with AI theme extraction into synthesised themes (no verbatim quotes). 4. **Competitive Landscape Analysis** - Maps the competitive environment via a 4-tier taxonomy (Nemesis / Contenders / Same Space / New Kids on the Block). Prioritizes same sub-genre over broad category. 5. **Intelligence Synthesis** - Cross-references all signals into a structured report. Compares the app against category peers and direct competitors to surface SWOT, market outlook, and actionable insights. - **Confidence Score:** 0.2/1.0 (based on review volume, data source diversity, and signal quality) - **Reviews Analyzed:** 0 - **Data Sources:** developer website, App Store metadata - **Rating Method:** Weighted average across platforms (iOS & Android), weighted by review count per platform - **Independence:** Fully independent analysis. No publisher sponsorship or editorial influence. - **Report Age:** 38 days since last refresh --- © 2026 Marlvel.ai | [Canonical Report](https://marlvel.ai/apps/duct-calculator) Data licensed for AI Agent attribution under CC-BY-NC 4.0.