1. What is CFM?

CFM (Cubic Feet per Minute) is a measurement of airflow volume, indicating how much air a ceiling fan can move per minute. It's a key metric for evaluating fan performance and efficiency.

2. How Does the Calculator Work?

The calculator uses the CFM equation:

Where:

• \( \pi \) — Approximately 3.14159
• \( r \) — Fan radius in feet (from center to tip of blade)
• \( v \) — Average air velocity in feet per minute

Explanation: The equation calculates the volume of air moved by multiplying the fan's sweep area by the air velocity.

3. Importance of CFM Calculation

Details: CFM helps compare fan performance regardless of size. Higher CFM means more air movement, but optimal CFM depends on room size and desired airflow.

4. Using the Calculator

Tips: Measure fan radius from center to blade tip in feet. Measure air velocity with an anemometer at the blade tips. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's a good CFM for a ceiling fan?
A: For bedrooms, 1,000-3,000 CFM is typical. Larger rooms may need 4,000-6,000 CFM. High-performance fans can exceed 7,000 CFM.

Q2: How does CFM relate to energy efficiency?
A: Look for high CFM with low wattage. CFM per watt (efficiency) is more important than CFM alone for energy-conscious buyers.

Q3: Does blade pitch affect CFM?
A: Yes, steeper blade pitches (10-15 degrees) generally move more air at the same RPM, increasing CFM.

Q4: Can I calculate CFM without an anemometer?
A: Some manufacturers provide CFM ratings. Without measurements, you can only estimate based on fan specifications.

Q5: How does CFM affect comfort?
A: Higher CFM creates stronger breezes for cooling, while lower CFM is better for gentle air circulation.