HVAC Load Calculator Manual J
Mike Watson Utilities iPhoneiPadiPod touch
HVAC Load Calculator Manual J is a free Utilities app for iPhone and iPad by Mike Watson. Rated 4.8/5 from 43 ratings. Requires iOS 16.0.
- Rating
- 4.8
- 43 ratings
- Price
- Free
- on the App Store
- Size
- 50 MB
- Age 4+
- Updated
- Oct 23
- 2026 · v1.33.0
Screenshots
About HVAC Load Calculator Manual J
The Manual J HVAC Load Calculator is the one HVAC contractors actually want to use. Stop overpaying for clunky, over-engineered calculators designed for engineers. HVAC Load Calculator brings professional Manual J calculations to your iPhone or iPad — clean, modern, offline-ready, and built for the field. BUILT FOR HVAC PROFESSIONALS Designed from scratch for techs in the field: large buttons you can tap with gloves on, fast calculations in the basement, and professional reports that win homeowner trust. THREE LEVELS OF ACCURACY Simple Mode Sized from your ZIP code's design conditions and the home's floor area. Get an estimate in under 60 seconds with zero measurements. Perfect for quick quotes and initial sales conversations. Moderate Mode – Standard Accuracy (Whole-House Block Load) Component-level factors: insulation quality, window types, foundation. The sweet spot for standard replacement jobs. Pro Mode – Professional Grade (Detailed Whole-House Block Load) Full MJ8 detail: per-direction window solar, measured airtightness, window ratings, overhang shading, and duct analysis. Maximizes equipment life and comfort — often right-sizing by 1+ ton. Best for new construction, high-performance builds, and detailed equipment sizing. MEASURE ROOMS WITH LiDAR — NEW On LiDAR-equipped iPhone and iPad Pro models (iOS 16+), walk each room and the app measures it for you — floor area, ceiling heights, windows, and exterior walls flow straight into your load calculation. Review each room, adjust with a tap, apply. Your PDF now includes a Room Measurements chapter with a sketch of each scanned room. NOW AVAILABLE IN US AND CANADA US Mode – ZIP code lookup backed by a climate database covering nearly 28,000 ZIP codes Metric Units – Toggle between Imperial and SI (kW, m², m³/h) throughout the app and PDF reports WORKS IN THE FIELD Offline-First – No signal in the basement? No problem. Everything runs locally on your device. Auto-Save Projects – Every calculation saves automatically. Never lose your work. iCloud Sync – Start a job on your iPhone, finish it on your iPad. Projects sync automatically across your devices. Professional PDF Reports – Generate and share detailed load reports from your phone or tablet. Add client name, site address, and job number — every report is stamped with a revision number and date, so everyone knows it's the latest version. Site Photo Documentation – Capture tagged photos, label by location and component, add notes, and include a professional photo appendix in your reports. iPad & Tablet Support – Optimized layouts give you more room to work on-site or back at the office. THE MATH YOU TRUST Calculations follow ACCA Manual J 8th Edition methodology: – Cooling BTU/hr (sensible and latent loads) – Heating BTU/hr – Recommended tonnage – Recommended furnace size – Manual S-based equipment sizing guidance – Kitchen and appliance heat gain If a result looks unusual for the home's size, the app flags it before the report goes out. WHY CONTRACTORS CHOOSE US – Modern, intuitive interface that makes sense the first time you use it – Dark mode and system theme support – Fast performance, even on older devices – Privacy-first: your data stays on your device and your own private iCloud — never our servers – Free to download — try it on your first calculations before subscribing PERFECT FOR – HVAC contractors, installers, and service techs – Sales teams quoting new systems – Independent contractors building their business – Home inspectors documenting HVAC systems No account. No setup. Just open the app and get to work. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Ratings & reviews
4.8
43 ratings
What’s new
Version 1.33.0 · Updated October 23, 2026
Rotation and foldables: the welcome slides and the photo viewer now stay on the page you were on when the screen turns or an iPhone unfolds. Room scanning: the Cancel button and the on-screen instructions stay clear of the notch and the home bar. New projects start with your last ZIP, Pro can fill typical R-values when you are stuck, operating cost picks a system in one tap, and the app interrupts less when you return to a project.
App privacy
The developer, Mike Watson, reported these privacy practices to Apple.
Data Not Linked to You
The following data, which may be collected but is not linked to your identity, may be used for the following purposes:
- Purchases: Purchase History
- Usage Data: Product Interaction
- Identifiers: Device ID
Used for: Analytics, App Functionality
Alternatives to HVAC Load Calculator Manual J
Looking for apps like HVAC Load Calculator Manual J? Here are 6 similar apps on the App Store. The highest rated is HVAC Load Calc: BTU Calculator (5.0/5), and all 6 are free to download.
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ScanPlan: HVAC Load & Ducts
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CoolCalc - HVAC Tools
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AC Calculator - HVAC Sizing
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Digiduct
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| App | Rating | Price | Last updated | Compare |
|---|---|---|---|---|
| HVAC Load Calculator Manual J | 4.8 / 5 (43 ratings) | Free | October 23, 2026 | |
| HVAC Load Calc: BTU Calculator | 5.0 / 5 (1) | Free | Oct 15, 2026 | Compare |
| Ductulator - Duct Calculator | 4.5 / 5 (34) | Free | Aug 24, 2026 | Compare |
| ScanPlan: HVAC Load & Ducts | 5.0 / 5 (1) | Free | Oct 25, 2026 | Compare |
| CoolCalc - HVAC Tools | 5.0 / 5 (1) | Free | Oct 24, 2026 | Compare |
| AC Calculator - HVAC Sizing | 4.8 / 5 (20) | Free | Apr 23, 2026 | Compare |
| Digiduct | 4.6 / 5 (11) | Free | Jul 9, 2026 | Compare |