Bedroom CFM Calculator
Supply airflow for a bedroom.
Enter your values
ⓘ Live results
Results
- Supply airflow
- 150 CFM
- Air changes
- 7.5
- Register size at 450 FPM
- 7.8 in equivalent
- Branch duct at 700 FPM
- 6.3 in dia
- Return path
- Undercut door or transfer grille
Quick answer
Bedrooms are typically supplied at about 1 CFM per square foot, or 4-5 air changes per hour.
CFM = area x 1 CFM per sq ft
How to use the Bedroom CFM Calculator
- 1Measure the bedroom floor area.
- 2Use 1 CFM per sq ft as a starting point, more for rooms with big west-facing glass.
- 3Give the room a return path so the door does not pressurise it.
Worked example
Using the values the calculator loads with:
Inputs
- Room area150 sq ft
- Ceiling height8 ft
- Airflow rate1 CFM/sq ft
Results
- Supply airflow150 CFM
- Air changes7.5
- Register size at 450 FPM7.8 in equivalent
- Branch duct at 700 FPM6.3 in dia
- Return pathUndercut door or transfer grille
Frequently asked questions
Why does a closed bedroom get stuffy?
Without a return path, supply air pressurises the room and airflow collapses.
Master bedroom?
Large or sun-exposed rooms often need 1.2-1.5 CFM per sq ft.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.