Calculations
Static Pressure in HVAC: Calculation Guide and Best Practices
Learn how to calculate static pressure in HVAC duct systems. Understand available static pressure, total external static pressure, and how it affects duct sizing.
Blog
Calculations
TEL: Total Effective Length Calculation Guide for HVAC Ducts
Learn how to calculate Total Effective Length (TEL) for HVAC duct sizing. Includes equivalent length tables for fittings, worked examples, and metal vs flex adjustments.
Calculations
CFM Formula for HVAC Systems: Every Equation You Need
All the essential CFM formulas for HVAC duct sizing in one place. Covers airflow calculation, BTU to CFM conversion, duct area formulas, and velocity relationships.
Calculations
BTU to Tonnage Conversion Guide for HVAC Systems
Convert BTU to tons for HVAC cooling systems. Learn the formula, see conversion tables, and understand how tonnage connects to CFM airflow and duct sizing.
HVAC Concepts
What Is Static Pressure in HVAC and How It Affects Your System
Static pressure in HVAC is the resistance to airflow measured in inches of water gauge. Learn what causes it, how to measure it, and why it matters for duct sizing.
HVAC Concepts
What Is Airflow Velocity in Ductwork and Why It Matters
Airflow velocity in HVAC ductwork is the speed of air moving through ducts, measured in feet per minute. Learn acceptable velocities, noise limits, and sizing impact.
HVAC Concepts
Supply vs Return Ductwork Explained
Understand the difference between supply and return ducts in HVAC systems. Learn how they work together, sizing differences, and why balanced airflow matters.
Technical Guide
A Complete Guide to Friction Rate in HVAC Design
Everything you need to know about friction rate in HVAC duct design: what it is, how to calculate it, common values, and best practices for different applications.
Practical Guide
Duct Sizing for Home HVAC: Room by Room Guide
Complete guide to sizing HVAC ducts for residential homes. Covers room by room CFM requirements, trunk and branch sizing, and practical tips for homeowners.
Practical Guide
Duct Sizing for Contractors: Job Site Reference Guide
A practical field guide for HVAC contractors covering duct sizing calculations, quick reference charts, installation tips, and common job site mistakes to avoid.
Troubleshooting
Wrong Duct Size Problems and How to Fix Them
Incorrectly sized ducts cause noise, comfort issues, high energy bills, and equipment failure. Learn how to identify wrong duct sizes and the solutions that work.
Troubleshooting
Noise in HVAC Duct Systems: Causes, Diagnosis, and Solutions
HVAC duct noise is caused by high velocity, undersized ducts, and poor fittings. Learn how to identify noise sources and fix them for quiet operation.