Air Infiltration Rate into Room (CFM) Calculator

Air Infiltration Rate Formula:

\[ CFM = ACH \times \left(\frac{V}{60}\right) \]

Air Infiltration Rate (CFM):

1. What is Air Infiltration Rate into Room (CFM)?

Definition: This calculator estimates the air infiltration rate (in cubic feet per minute) based on the number of air changes per hour and room volume.

Purpose: It helps HVAC professionals and building engineers determine the rate at which outside air enters a room through leaks and openings.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ CFM = ACH \times \left(\frac{V}{60}\right) \]

Where:

\( CFM \) — Air infiltration rate (cubic feet per minute)
\( ACH \) — Number of air changes per hour (±5%)
\( V \) — Room volume (cubic feet ±5%)

Explanation: The room volume is divided by 60 to convert from hours to minutes, then multiplied by the air changes per hour.

3. Importance of Air Infiltration Rate Calculation

Details: Proper air infiltration estimation ensures adequate ventilation, energy efficiency, and indoor air quality in buildings.

4. Using the Calculator

Tips: Enter the number of air changes per hour (ACH) and room volume in cubic feet. Both values must be > 0. Results have ±5% accuracy.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical ACH value for homes?
A: Older homes might have 0.5-1.5 ACH, while newer, tighter homes might have 0.1-0.5 ACH.

Q2: Why is there a ±5% margin?
A: Air infiltration rates can vary due to building tightness, wind conditions, and temperature differences.

Q3: How do I measure room volume?
A: Multiply length × width × height of the room in feet to get cubic feet.

Q4: What affects air infiltration rates?
A: Building age, construction quality, window/door seals, and weather conditions all affect infiltration.

Q5: When would I need this calculation?
A: For HVAC system design, ventilation planning, energy audits, and indoor air quality assessments.