Still Dealing With Callbacks From Oversized Systems?
Stop guessing tonnage. Get Manual J–aligned load calculations inspectors accept, homeowners trust, and you can defend — in under 5 minutes.
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⚡ Built by HVAC techs. Used daily on real installs.
Trusted by professionals who work with
Why HVAC Professionals Choose Us
No callbacks. No guesswork. Just calculations you can stand behind.
Defensible, Manual J–Aligned Results
Built around ACCA Manual J methodology so you can clearly explain why a system was sized the way it was — to homeowners, inspectors, and utilities.
Accurate Sizing in Minutes — Not Hours
Step-by-step inputs guide you through the right assumptions without drowning you in engineering complexity.
Reports Inspectors Actually Accept
Clear assumptions, room-by-room loads, and documented inputs — formatted for permits, audits, and rebates.
Hybrid Room Intelligence
Our unique hybrid approach combines whole-house calculations with targeted room analysis. Flag problem rooms — heating or cooling — without measuring every single space.
- Identify comfort problem areas (too hot or too cold)
- Get airflow distribution recommendations
- Avoid oversizing while addressing hot/cold spots
- No complex room-by-room measurements
Everything You Need
A complete toolkit for professional HVAC load calculations.
BTU Calculations
Sensible, latent, and total load for heating and cooling
Tonnage Range
Recommended equipment size with field flexibility
CFM Targets
Airflow recommendations adjusted for climate
Risk Analysis
Warnings for oversizing, humidity, and comfort
Saved Projects
All calculations saved for future reference
PDF Reports
Professional reports for customers and records
Assumption Docs
Every input and assumption documented
Edit & Rerun
Change inputs and recalculate instantly
What Our Customers Say
Join thousands of HVAC professionals who trust their calculations.
“This tool paid for itself the first week. I used to spend 30 minutes per calc with spreadsheets. Now it takes me 5 minutes and I get a professional PDF to hand the customer.”
James Mitchell
Owner, Mitchell HVAC Services · Dallas, TX
“The defensible assumptions feature is a game-changer. Had an inspector question my sizing and I pulled up the report right there. Every assumption documented. He signed off immediately.”
Karen Sullivan
Lead Tech, ComfortFirst Heating & Air · Denver, CO
“I love the problem room feature. Customer complained about a hot bedroom upstairs. I flagged it in the calc and the report showed exactly why it needed an extra supply run. Very professional.”
Robert Torres
Residential Specialist · Phoenix, AZ
“Switched from doing rule-of-thumb estimates to this. My close rate went up 20% because customers see I'm doing real calculations, not guessing. Worth every penny.”
David Lee
Sales Manager, Arctic Air Solutions · Atlanta, GA
“Finally a load calc tool that doesn't require a PhD. I trained my junior techs in 10 minutes. They're doing better calcs than I used to with pen and paper.”
Mike Patterson
Field Supervisor · Chicago, IL
“We run 15+ calcs a week. The saved projects and PDF reports keep everything organized. Our office manager loves that everything is in one place now.”
Sarah Chen
Operations Director, Premier Climate · Seattle, WA
Plans That Pay for Themselves
One accurate load calc can save thousands in callbacks. Start with 3 free — no credit card required.
Free Trial
Try before you buy
First 3 calculations only
- 3 free calculations
- Full load calculation engine
- PDF report generation
- Problem room analysis
- Risk warnings
- Unlimited saved projects
Pro
For individual technicians
- Unlimited calculations
- Full load calculation engine
- PDF report generation
- Problem room analysis
- Risk warnings & recommendations
- Unlimited saved projects
- Priority email support
Team
For HVAC companies
- Everything in Pro
- Multiple user accounts
- Team project sharing
- Company branding on reports
- Admin dashboard
- Dedicated account manager
- Phone & email support
10,000+
Active Technicians
250,000+
Calculations Run
98%
Customer Satisfaction
< 5 min
Average Calc Time