Design Every Duct Run Right. No More Airflow Complaints.
Field-ready duct sizing formulas, Manual D workflows, and ChatGPT prompts that let any tech calculate CFM, static pressure, and duct dimensions — without guessing.
Instant download · Works for residential and commercial systems · Based on Manual D & ACCA standards
Undersized ducts starve equipment. Oversized ducts waste sheet metal and spike static pressure. Most callbacks trace back to duct design that was eyeballed, not calculated. This guide gives you the formulas, the worksheets, and the ChatGPT prompts to size it correctly — every time.
Every Duct Sizing Tool You Need, Built for the Field
Complete Manual D Duct Sizing System
The full duct sizing methodology condensed into practical worksheets — from friction rate to final duct dimensions, every calculation covered.
- Friction rate calculations and equivalent length tables
- CFM distribution worksheets for residential and commercial
- Static pressure drop formulas for every duct type
- Trunk, branch, and flex duct sizing quick-reference charts
ChatGPT Prompt Templates
AI prompts for sizing checks, load distribution, and troubleshooting noisy ducts.
Common Duct Defects Checklist
Short-cycling, static spikes, hot/cold spots — how to diagnose and fix.
ACCA Manual D Quick Reference
Condensed version of the key tables and formulas field techs actually use.
Instant Download
PDF format, works on any device. Use it on the job from day one.
Built for Every Tech Who Designs or Hangs Ductwork
The Sheet Metal Tech
You're cutting and hanging every day but sizing by feel. This gives you the formulas to back every decision.
The Service Manager
Tired of callbacks on installs your team signed off on? Standardize their duct sizing with this kit.
The HVAC Student
Manual D is on your exam and on every job. Learn it once from a practical field guide, not a textbook.
From Techs Who Size Every Duct Run Right
“We were getting static pressure complaints on a new install. Used the friction rate tables in this guide and found the trunk was undersized by 30%. Fixed it in an afternoon.”
Travis H.
Sheet Metal Tech, Houston TX
“Saved this on my tablet. The CFM distribution worksheet alone is worth the price — I use it on every estimate.”
Kevin M.
HVAC Estimator, Orlando FL
“Passed my NATE installation specialty section after studying this. The Manual D section is exactly what they test.”
Andre S.
HVAC Technician, Las Vegas NV
Stop Eyeballing Duct Runs. Size Them Right.
One bad duct design creates callbacks for years. Get the formulas, the worksheets, and the AI prompts that make every install defensible.
Instant download · Stripe secure checkout · 30-day access guarantee