1. What is CFM?

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

2. How Does the Calculator Work?

The calculator uses the CFM formula:

Where:

• \( Volume \) — Space volume in cubic feet
• \( Air\ Changes\ per\ Hour \) — Desired air changes per hour (ACH)
• 60 — Conversion factor from hours to minutes

Explanation: The formula converts the total air volume needed per hour into the required airflow rate per minute for ventilation systems.

3. Importance of CFM Calculation

Details: Proper CFM calculation ensures adequate ventilation for indoor air quality, controls humidity, removes contaminants, and maintains comfortable conditions in buildings.

4. Using the Calculator

Tips: Enter the room volume in cubic feet (length × width × height) and the desired air changes per hour. Typical ACH values range from 4-6 for general spaces to 10-15 for areas needing more ventilation.

5. Frequently Asked Questions (FAQ)

Q1: What are typical ACH values for different spaces?
A: Living rooms: 4-6 ACH, Kitchens: 7-8 ACH, Bathrooms: 8-10 ACH, Laboratories: 10-15 ACH, Clean rooms: 20-30+ ACH.

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

Q3: Does CFM account for duct losses?
A: No, this calculates theoretical CFM. Actual system CFM should be higher to account for ductwork losses (typically add 20-30%).

Q4: How does CFM relate to fan selection?
A: Fans should be selected to meet or exceed the calculated CFM at the system's static pressure.

Q5: Can I use this for whole-house ventilation?
A: Yes, sum the CFM requirements for all rooms or calculate based on total house volume and desired ACH.