1. What is a Ventilation Rate Calculator?

Definition: This calculator determines the required ventilation rate for a room based on air changes per hour (ACH) and room volume.

Purpose: It helps HVAC professionals, architects, and building designers ensure proper air circulation in enclosed spaces.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• Ventilation Rate — Cubic feet per minute (cfm) of air flow needed
• ACH — Air changes per hour (how many times the air is replaced)
• Volume — Room volume in cubic feet (length × width × height)

Explanation: The formula converts hourly air changes to minute-based ventilation rate required for HVAC system design.

3. Importance of Ventilation Calculation

Details: Proper ventilation maintains indoor air quality, controls humidity, removes contaminants, and ensures occupant comfort and health.

4. Using the Calculator

Tips: Enter the required ACH (based on room type) and room volume in cubic feet. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What are typical ACH values?
A: Offices: 4-6 ACH, Kitchens: 15-20 ACH, Bathrooms: 6-8 ACH, Hospitals: 12-15 ACH.

Q2: How do I calculate room volume?
A: Multiply length × width × height in feet. For irregular rooms, divide into rectangular sections.

Q3: Why divide by 60 in the formula?
A: To convert from hourly rate (ACH) to minute rate (cfm) since there are 60 minutes in an hour.

Q4: Does this account for occupancy?
A: No, for occupied spaces, also consider ASHRAE standards of 15-20 cfm per person.

Q5: How do I measure existing ventilation?
A: Use an anemometer to measure air velocity and multiply by duct cross-sectional area.