Duct Size Chart

The Duct Size Chart provides recommended duct sizes for different airflow rates, including the corresponding round duct diameter and rectangular duct size.
Airflow (CFM) Round Duct Diameter (inches) Rectangular Duct Size (W x H) – inches
50 4 6 x 4
100 6 8 x 6
150 7 10 x 6
200 8 12 x 8
250 9 14 x 8
300 10 16 x 8
400 12 18 x 10
500 14 20 x 12
600 15 22 x 12
700 16 24 x 12
800 18 24 x 14
900 18 26 x 14
1000 20 28 x 14

The Duct Size Chart provided displays the corresponding round duct diameter and rectangular duct size based on the required airflow in cubic feet per minute (CFM). This chart is useful for HVAC professionals and designers who need to determine the appropriate duct sizes for specific airflow requirements. By referencing this chart, professionals can select the appropriate duct diameter and dimensions to ensure efficient and effective airflow in their HVAC systems.


What is a duct size chart?

A duct size chart is a reference tool that provides guidance on selecting the appropriate duct size for a given airflow volume.

How is a duct size chart used?

A duct size chart is used by HVAC professionals to calculate the required duct size based on the desired airflow rate, system pressure drop, and other factors.

What information does a duct size chart typically include?

A duct size chart usually includes various columns or sections that provide information on the airflow capacity, recommended duct size, and corresponding duct dimensions for different types of ductwork.

Can a duct size chart be used for both residential and commercial applications?

Yes, a duct size chart can be used for both residential and commercial HVAC systems as the principles of airflow and duct sizing apply to various types of installations.

Are duct size charts standardized?

There are industry standards and guidelines for duct sizing, and many manufacturers and professional organizations provide their own duct size charts. While there may be some variations, the overall principles and calculations remain consistent.

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