HVAC Airflow Per Room Calculator (CFM & Register Sizing)
Calculate required CFM per room, size supply registers, and verify total system airflow balance against equipment tonnage. Based on industry-standard sq ft airflow methods used by HVAC designers.
| Room Name | Sq Ft | Required CFM | Reg. Qty | CFM / Register | Del |
|---|---|---|---|---|---|
| TOTALS → | — | — | |||
How to Calculate Airflow Per Room
Calculating the airflow required for each room is a critical step in proper HVAC system design. This ensures that every space receives sufficient heating and cooling to maintain comfortable temperatures year-round.
Why is room-by-room CFM important?
Without accurate room-by-room calculation, a system can deliver too much air to small rooms while starving larger, high-load areas (like great rooms with vaulted ceilings). This leads to hot and cold spots throughout the house. Proper airflow balancing also protects your equipment from static pressure issues caused by undersized or oversized register arrays.
Pair this tool with the CFM Calculator for total system airflow, and the Duct Size Calculator to dimension your supply trunks and branch runs based on each room's CFM requirement.