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How To Calculate CFM Per Room In Air Conditioning

CFM Calculation Formula:

\[ CFM = \frac{V \times ACH}{60} \]

cubic feet
changes/hour

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1. What is CFM Calculation?

CFM (Cubic Feet per Minute) calculation determines the airflow rate required for proper ventilation and air conditioning in a room. It ensures adequate air changes to maintain indoor air quality and thermal comfort.

2. How Does the Calculator Work?

The calculator uses the CFM formula:

\[ CFM = \frac{V \times ACH}{60} \]

Where:

Explanation: The formula converts hourly air change requirements to minute-based airflow rate, providing the CFM needed for proper room ventilation.

3. Importance of CFM Calculation

Details: Accurate CFM calculation is essential for designing efficient HVAC systems, ensuring proper air distribution, maintaining indoor air quality, and achieving energy efficiency in building ventilation.

4. Using the Calculator

Tips: Enter room volume in cubic feet and required air changes per hour. Calculate room volume by multiplying length × width × height. Typical ACH values range from 4-8 for residential spaces and 6-20 for commercial applications.

5. Frequently Asked Questions (FAQ)

Q1: What are typical ACH values for different rooms?
A: Living rooms: 4-6 ACH, Bedrooms: 4-6 ACH, Kitchens: 6-8 ACH, Bathrooms: 8-10 ACH, Commercial spaces: 6-20 ACH depending on occupancy and activity.

Q2: How do I calculate room volume?
A: Measure room length, width, and height in feet, then multiply: Volume = Length × Width × Height (all in feet).

Q3: Why divide by 60 in the formula?
A: ACH is per hour, while CFM is per minute. Dividing by 60 converts hourly rate to minute rate.

Q4: What factors affect ACH requirements?
A: Room usage, occupancy, heat loads, air quality requirements, local building codes, and specific activities in the space.

Q5: Can this calculator be used for HVAC system design?
A: Yes, this provides the basic CFM requirement, but professional HVAC design should consider additional factors like duct sizing, static pressure, and system efficiency.

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