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TrowlCalc / HVAC · Division 23

HVAC calculators

Air that moves the way the room needs.

CFM Calculator Airflow from room volume and air changes per hour

Up next: BTU sizing, air changes per hour, and duct CFM.

TrowlCalc — construction calculators that answer in materials, not math.

Every calculation runs in your browser — dimensions and prices never leave your device. No signup, no tracking of your numbers.

Estimates, not advice — verify before you order or build · About · Editorial standards