Air Balance Calculator

Calculate building air balance, pressurization status, and required adjustments from supply, return, exhaust, and outside air flows.

Supply Air

CFM

Return Air

CFM

Exhaust Air

CFM

Outside Air

CFM

ASHRAE 62.1 Table 6.2.2.1: offices 5 CFM/person+0.06 CFM/ft²; classrooms 10 CFM/person+0.12 CFM/ft²

Transfer Air

CFM

Tab to move between fields

Net Air Balance

500 CFM

Pressurization

1 (1=Positive, 2=Negative, 3=Neutral)

Balance Ratio110%

Adjustment Needed-500 CFM

How to Use This Calculator

Enter Supply Air, Return Air, and Exhaust Air.
Set Outside Air and Transfer Air.
Review Net Air Balance (CFM) and Pressurization ((1=Positive, 2=Negative, 3=Neutral)).
Use Balance Ratio (%) and Adjustment Needed (CFM) to inform your decision.

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