1. What is CFM Calculation?

CFM (Cubic Feet per Minute) calculation determines the airflow required to properly ventilate a space based on room volume and desired air changes per hour. It's essential for HVAC system design and indoor air quality management.

2. How Does the Calculator Work?

The calculator uses the CFM equation:

Where:

• \( Room\ Volume \) — Space volume in cubic feet
• \( ACH \) — Air changes per hour (dimensionless)
• 60 — Conversion factor from hours to minutes

Explanation: The equation converts the total air volume needed per hour into the required airflow rate per minute.

3. Importance of CFM Calculation

Details: Proper CFM calculation ensures adequate ventilation, maintains indoor air quality, prevents moisture buildup, and meets building code requirements.

4. Using the Calculator

Tips: Enter room volume in cubic feet (length × width × height) and desired air changes per hour. Typical ACH values range from 2-4 for living spaces to 6-12 for kitchens/bathrooms.

5. Frequently Asked Questions (FAQ)

Q1: What are typical ACH values for different rooms?
A: Living rooms: 2-4, Bedrooms: 4-6, Bathrooms: 6-8, Kitchens: 8-12, Commercial kitchens: 15-30.

Q2: How do I measure room volume?
A: Multiply length × width × height in feet. For irregular spaces, divide into regular shapes and sum volumes.

Q3: Does CFM requirement change with occupancy?
A: Yes, crowded spaces may need higher ACH. Some calculations use people count (CFM per person).

Q4: What about ductwork and system efficiency?
A: Actual system CFM should account for duct losses (typically add 10-20% to calculated CFM).

Q5: How does this relate to fan selection?
A: Choose a fan with CFM rating matching or exceeding your calculated requirement at expected static pressure.