1. What is CFM?

CFM (Cubic Feet per Minute) is a measurement of airflow volume, indicating how many cubic feet of air pass by a stationary point in one minute. It's commonly used in HVAC systems, ventilation, and ductwork design.

2. How Does the Calculator Work?

The calculator uses the CFM formula:

Where:

• \( CFM \) — Cubic Feet per Minute (ft³/min)
• \( Area \) — Cross-sectional area of duct or opening (ft²)
• \( Velocity \) — Air velocity through the area (fpm)

Explanation: The formula calculates the volume of air moving through a given cross-sectional area at a specific velocity over one minute.

3. Importance of CFM Calculation

Details: Accurate CFM calculation is essential for proper HVAC system design, ventilation requirements, energy efficiency optimization, and ensuring adequate air quality in buildings.

4. Using the Calculator

Tips: Enter area in square feet (ft²) and velocity in feet per minute (fpm). Both values must be positive numbers. The calculator will compute the CFM automatically.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical CFM range for residential HVAC?
A: Residential systems typically range from 400-2000 CFM depending on the size of the home and system capacity.

Q2: How do I measure duct area?
A: For rectangular ducts: Area = width × height. For round ducts: Area = π × (diameter/2)².

Q3: What is a good air velocity for ductwork?
A: Typically 600-900 fpm for main ducts and 400-700 fpm for branch ducts to balance efficiency and noise.

Q4: Why is CFM important in ventilation?
A: CFM determines how quickly air is exchanged in a space, affecting air quality, humidity control, and contaminant removal.

Q5: Can CFM be converted to other units?
A: Yes, 1 CFM = 0.0004719 m³/s or 1.699 m³/h. Conversion factors vary based on the target unit system.