First Report 100% Free — No Credit Card Required

Free Manual J Calculator — Professional HVAC Load Calculations in 60 Seconds

Upload your blueprint. Get a Manual J report following ACCA methodology with room-by-room loads and equipment sizing. No software to install, no training required.

No credit card required -- No software to download -- ACCA Manual J methodology

2,500+
Projects Completed
60 sec
Average Turnaround
98%
Permit Approval Rate
4.8/5
Customer Rating

How Our Free Manual J Calculator Works

Three steps. 60 seconds. Permit-ready Manual J results.

1

Upload Your Blueprint

Upload any blueprint PDF — floor plans, elevations, energy specs. Our AI reads them all automatically. Drag and drop or browse to upload.

2

AI Analyzes Your Plans

Our two-brain AI system extracts dimensions, R-values, windows, orientation, and 30+ Manual J factors directly from your blueprint. No manual data entry.

3

Get Your Free Report

Download a complete Manual J report with room-by-room heating and cooling loads, equipment sizing, and a permit-ready PDF. First report is free.

No account required for your first report

AutoHVAC vs. Traditional Manual J Software

See why HVAC professionals are switching from expensive desktop software to AutoHVAC's free Manual J calculator.

AutoHVAC

Recommended
Free OptionFree first report
Monthly Cost$47/mo after
Speed60 seconds
AI Blueprint Reading
No Software Install
Mobile / Tablet
Training RequiredNone required

Wrightsoft

Free OptionNo free option
Monthly Cost$99-$199/mo
Speed30-60 minutes
AI Blueprint Reading
No Software Install
Mobile / Tablet
Training Required8+ hours

CoolCalc

Free OptionLimited free
Monthly Cost$49/mo
Speed20-45 minutes
AI Blueprint Reading
No Software Install
Mobile / Tablet
Training Required2-4 hours

Elite RHVAC

Free OptionNo free option
Monthly Cost$499 one-time
Speed45-90 minutes
AI Blueprint Reading
No Software Install
Mobile / Tablet
Training Required4-8 hours

No credit card required

What You Get in Your Free Manual J Report

Every report includes everything you need for proper HVAC sizing and permit approval.

Heating & Cooling Loads

Precise BTU/hr calculations for both heating and cooling, factoring in your local design temperatures and climate zone.

Room-by-Room Breakdown

Individual load calculations for each room with CFM airflow requirements for proper duct design and balancing.

Permit-Ready PDF

Professional documentation that meets ACCA standards and building department requirements. Ready to submit for permits.

Equipment Sizing

Furnace capacity and AC tonnage recommendations based on your calculated loads. No more guessing on equipment size.

Trusted by HVAC Professionals Nationwide

Contractors, engineers, and inspectors rely on AutoHVAC for fast, accurate Manual J calculations.

AutoHVAC cut my bid prep time from 4 hours to 15 minutes. The calculations are spot-on and the reports look professional.
Mike Rodriguez
HVAC Contractor -- Phoenix, AZ
Finally, a tool that understands real-world HVAC design. The Manual J calculations match our in-house engineering, but delivered in seconds.
Sarah Chen
Mechanical Engineer -- Seattle, WA
Contractors using AutoHVAC submit cleaner, more accurate plans. Fewer revision cycles mean faster permit approvals for everyone.
Tom Anderson
Building Inspector -- Denver, CO
2,500+
Projects Completed
98%
Permit Approval Rate
4.2 hrs
Average Time Saved
50+
States Supported

Why “Free BTU Calculators” Get It Wrong

Simple square-footage calculators ignore the factors that actually determine your HVAC load. That is why they are typically off by 30-50%.

Simple BTU Calculators

  • Ask for square footage only — ignore construction
  • Use outdated rules of thumb (1 ton per 500 sqft)
  • Ignore insulation R-values and window specs
  • Don't factor in infiltration or duct losses
  • Cannot produce permit-ready documentation

AutoHVAC Manual J

  • AI reads your actual blueprint — extracts real specs
  • Full ACCA Manual J 8th Edition methodology
  • Analyzes R-values, U-factors, SHGC, and orientation
  • Calculates infiltration, ventilation, and duct losses
  • Generates permit-ready PDF reports instantly

Want a quick estimate before your full Manual J? Our BTU calculator and AC tonnage calculator give you a starting point -- then upload your blueprint for precise Manual J results.

Free Manual J Calculator FAQ

Everything you need to know about getting a free Manual J calculation online.

Still Have Questions?

Get instant, accurate HVAC load calculations with our free calculator.

Get Your Free Manual J in 60 Seconds

Stop guessing at equipment sizes. Stop paying hundreds for Manual J reports. Upload your blueprint and get accurate, permit-ready results — first one is on us.

No credit card required -- No software to install -- ACCA Manual J methodology