Showing Posts From
Cfm
Duct Size Chart: How to Match Duct Size to CFM
A round duct size chart by CFM, what a ductulator actually does, the friction-rate and velocity rules behind it, how to convert round to rectangular, and how to size supply vs return ducts.
Return Air Duct Sizing: How to Size the Return Side
How to size return air ducts: why returns must match supply airflow, a return duct size chart by CFM, single vs multiple returns, filter grille sizing, and the static-pressure problems undersizing causes.
Essential HVAC Formulas Every Tech Should Know
The core HVAC formulas in one place: sensible and latent heat, total heat, CFM, tonnage, delta T, static pressure, SEER/EER, and the constants behind them, with worked examples.
What Is CFM and How to Calculate It
CFM is the volume of air your HVAC system moves per minute. What it means, the 400 CFM per ton rule, the formula to size airflow per room, and how to measure it.