CFM Calculator
Calculate cubic feet per minute (CFM) airflow requirements for proper ventilation
Calculate Airflow Requirements
Typical residential ceiling height: 8-10 feet
Custom ACH Value
Number of times the entire room air volume is replaced per hour
Airflow Requirements
Ventilation Assessment: Good Ventilation
Adequate air changes for comfort and air quality.
💨 HVAC Design Notice
• These calculations provide baseline ventilation requirements
• Consider local building codes and ASHRAE standards
• Factor in equipment efficiency, ductwork losses, and static pressure
• Consult HVAC professionals for complex systems and commercial applications
• Consider humidity control, air filtration, and energy efficiency
Example Calculation: Kitchen Ventilation
Kitchen Specifications
Dimensions: 12 ft × 10 ft × 8 ft ceiling
Floor Area: 120 ft²
Room Volume: 960 ft³
Recommended ACH: 7.5 (kitchen standard)
CFM Calculation
CFM = (Floor Area × Ceiling Height × ACH) ÷ 60
CFM = (120 ft² × 8 ft × 7.5 ACH) ÷ 60
CFM = 7,200 ÷ 60 = 120 CFM
Result: Install exhaust fan rated for minimum 120 CFM
Recommended ACH by Room
Residential
CFM Guidelines
Exhaust Fans
Bathroom: 50-80 CFM, Kitchen: 100-300 CFM
Whole House
0.35 ACH minimum for energy efficiency
Commercial
Follow ASHRAE 62.1 standards
Industrial
Varies by process and safety requirements
Quick Conversions
Understanding CFM and Ventilation Requirements
What is CFM?
CFM (Cubic Feet per Minute) is a measurement of volumetric airflow. It represents how many cubic feet of air pass through a space in one minute, making it essential for sizing ventilation systems, exhaust fans, and HVAC equipment.
Why Proper Ventilation Matters
- •Removes indoor air pollutants and odors
- •Controls humidity and prevents mold growth
- •Maintains comfortable temperatures
- •Provides fresh oxygen for occupants
CFM Calculation Formula
CFM = (Floor Area × Ceiling Height × ACH) ÷ 60
- Floor Area: Room area in square feet
- Ceiling Height: Room height in feet
- ACH: Air Changes per Hour required
- ÷ 60: Convert hours to minutes
Applications
Exhaust Fan Sizing
Determine the right CFM rating for bathroom and kitchen exhaust fans.
HVAC System Design
Calculate supply and return air requirements for heating and cooling systems.
Indoor Air Quality
Ensure adequate fresh air exchange to maintain healthy indoor environments.