Q:

What is the CFM formula for HVAC?

A:

The formula used to determine the amount of CFM, or cubic feet per minute, a room needs for heating begins by multiplying the room's volume by the number of times the heated air gets changed hourly. Then divide the resulting number by 60 to produce the amount of CFM required.

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To determine the room's volume for the first step in the formula, the room's length, width and height must be multiplied together. When this volume is multiplied by the hourly air changes, the resulting number is the amount of cubic feet of air that passes through that room hourly. The cubic feet is then divided by 60 in the final step, since there are 60 minutes in an hour. The resulting CFM refers to how many cubic feet of air must be fed into that room every minute.

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Related Questions

• A:

A duct calculator measures air velocity by using a formula in which air flow is a variable expressed in cubic feet per minute, or CFM. Heating, ventilation and air conditioning professionals commonly use duct calculators.

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• A:

Cubic feet per minute is calculated by multiplying air velocity by area. In the case of air conditioning units, the volumetric flow rate can be calculated by multiplying the air velocity by the area of the AC duct.

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• A:

Some good ways to measure CFM include using a measurement from an air balancing hood and measuring the airflow with an anemometer. CFM stands for cubic feet per minute, and is used to measure how much air a ventilation system is capable of pushing.