HVAC Load Calculator Manual J

The Manual J load calculator HVAC contractors actually want to use.


Stop paying $40 for clunky, over-engineered calculators designed for engineers. HVAC Load Calculator brings professional Manual J calculations to your iPhone in a clean, modern app that works offline and gets out of your way.


BUILT FOR CONTRACTORS, NOT ENGINEERS
Unlike expensive desktop software ported to mobile, we designed this from scratch for techs working in the field. Large buttons you can tap with gloves on. Fast calculations while standing in a basement. Professional reports that win homeowner trust.


TWO CALCULATION MODES AVAILABLE NOW
Simple Mode – 8 inputs, ±15-20% accuracy
Perfect for quick quotes and ballpark estimates. Get in, get your numbers, get on with the job. Fast enough to do while talking with a homeowner.

Moderate Mode – 15 inputs, ±10-15% accuracy
The sweet spot for most residential jobs. Enough detail to be professional without the headache. Gives you precision when you need it.

Comprehensive Mode – 25+ inputs, ±5-10% accuracy
Full ACCA Manual J methodology for complex projects. Coming soon.


WORKS IN THE FIELD
- Offline-First – No cell service in the basement? No problem. Everything runs locally on your device.
- Auto-Save Projects – Never lose your work. Every calculation saves automatically.
- ZIP Code Climate Database – Instant lookup for 80+ major US cities with smart fallback for any location.
- Professional PDF Reports – Generate and share detailed load reports directly from your iPhone.


WHY CONTRACTORS CHOOSE US
Modern Interface – Clean, intuitive design that makes sense the first time you use it.
Fast Performance – Instant calculations, even on older iPhones.
Completely Free – No upfront cost, no hidden fees, no subscriptions.
Privacy-First – Your data stays on your device. We never see your projects or customer information.


THE MATH YOU TRUST
Our calculations follow ACCA Manual J 8th Edition methodology. You get:

- Cooling BTU/hr (sensible and latent loads)
- Heating BTU/hr
- Recommended tonnage (rounded to 0.5 tons)
- Recommended furnace size (rounded to 5,000 BTU)
- Manual S equipment sizing guidance

All calculations use industry-standard formulas trusted by HVAC professionals nationwide.


PERFECT FOR
- HVAC contractors and installers
- Service technicians sizing replacements
- Sales teams quoting new systems
- In