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Free Manual J Calculator

Get accurate, permit-ready HVAC load calculations in 60 seconds. Just upload your blueprint—our AI does the rest.

Get Your Free Manual J Report

No credit card required • Results in 60 seconds

Why Most Manual J Calculators Give Wrong Answers

Simple "BTU per square foot" calculators ignore the factors that actually determine your load. Here's what they miss—and why it matters.

Simple "Calculators"

  • Ask for square footage only
  • Use outdated "rules of thumb"
  • Ignore actual construction details
  • Can't pass permit inspection
  • Off by 30-50% on average

⚠️ Wrong-sized equipment = callbacks, comfort complaints, and unhappy customers

AutoHVAC Manual J

  • AI reads your actual blueprint
  • Analyzes 30+ ACCA Manual J factors
  • Extracts R-values, windows, orientation
  • Permit-ready PDF reports
  • Results in 60 seconds

The Real Cost of Wrong-Sized Equipment

HVAC contractors lose thousands of dollars per year on callbacks from improperly sized systems

Undersized Equipment

  • • Can't maintain comfort on design days
  • • Runs constantly, increasing wear
  • • Higher utility bills for homeowner
  • • Shortened equipment lifespan
  • Guaranteed callback

Oversized Equipment

  • • Short-cycles, causing humidity issues
  • • Uneven temperatures room to room
  • • Higher upfront equipment cost
  • • Increased energy consumption
  • "It's too humid" complaints

Proper Manual J sizing eliminates these problems before they start

Get Accurate Sizing Free

How Our Manual J Calculator Works

Three steps. 60 seconds. Permit-ready results.

Step 1

Upload Your Blueprint

Upload any blueprint PDF. Floor plans, elevation drawings, energy specs—our AI reads them all.

Step 2

AI Analysis

Our AI extracts dimensions, R-values, windows, and construction details. Full Manual J methodology.

Step 3

Get Your Report

Download a complete, permit-ready Manual J report with room-by-room loads and equipment sizing.

What's Included in Your Manual J Report

Heating & Cooling Loads

Precise BTU/hr requirements for both heating and cooling based on your climate zone.

Room-by-Room Breakdown

Individual load calculations for each room with CFM requirements for duct design.

Permit-Ready PDF

Professional documentation that meets building department requirements.

Equipment Sizing

Furnace and AC tonnage recommendations based on calculated loads.

Get Your Free Manual J in 60 Seconds

Stop guessing. Stop using outdated rules of thumb. Upload your blueprint and get accurate, permit-ready load calculations—first one's free.

Upload Blueprint & Get Free Report

No credit card required • No software to install • Results in 60 seconds