Duct CFM charts provide valuable information for determining the appropriate sizing of flexible and round ducts based on the desired airflow rate, measured in cubic feet per minute (CFM). These charts are essential for HVAC professionals and individuals involved in duct system design, installation, or modification.
The duct CFM chart typically includes different duct sizes, such as 4, 6, 8, 10, and 12 inches, along with corresponding CFM values. By referencing the chart, you can identify the recommended CFM for a specific duct size. This helps ensure that the duct system can adequately deliver the required airflow to maintain proper ventilation and temperature control in a space.
When selecting a duct size, it is crucial to consider factors such as the type of HVAC system, the distance the air needs to travel, and any restrictions or obstacles that may affect airflow. By using the duct CFM chart, you can match the desired CFM with the appropriate duct size to optimize system performance and efficiency.
However, it’s important to note that duct sizing is a complex process that involves various factors beyond CFM, such as duct length, static pressure, and duct material. For accurate and comprehensive duct system design, it is recommended to consult with an HVAC professional who can perform detailed calculations and consider all relevant variables to ensure proper airflow distribution and system performance.
Example: The duct CFM chart helps determine the appropriate duct size based on desired airflow rates. For example, if you need a CFM of 400, the chart may indicate a recommended 6-inch duct. By following the chart, you can select the right duct size to ensure proper airflow in your HVAC system. However, it’s important to consult with an HVAC professional for accurate duct sizing, as other factors like duct length and static pressure should also be considered.
CFM Sizing Chart For Flex Round Ducts (50-1,700 CFM)
| Duct Size (inch) | Flex Duct Airflow (CFM) |
|---|---|
| 4 | 50-70 |
| 5 | 75-100 |
| 6 | 100-150 |
| 7 | 150-200 |
| 8 | 200-250 |
| 9 | 250-300 |
| 10 | 300-400 |
| 11 | 400-500 |
| 12 | 500-600 |
| 13 | 600-700 |
| 14 | 700-800 |
| 15 | 800-900 |
| 16 | 900-1,000 |
| 17 | 1,000-1,100 |
| 18 | 1,100-1,200 |
| 19 | 1,200-1,300 |
| 20 | 1,300-1,700 |
Please note that the values provided in the table are approximate ranges and may vary depending on specific system requirements and conditions. It is always recommended to consult with a professional HVAC engineer or technician for accurate duct sizing calculations based on the specific needs of your HVAC system.
CFM Sizing Chart For Metal Round Ducts (50-2,000 CFM)
| Duct Size (inch) | Metal Duct Airflow (CFM) |
|---|---|
| 4 | 20-40 |
| 5 | 30-50 |
| 6 | 40-80 |
| 7 | 50-100 |
| 8 | 70-120 |
| 9 | 80-150 |
| 10 | 100-200 |
| 11 | 120-250 |
| 12 | 140-300 |
| 13 | 160-350 |
| 14 | 180-400 |
| 15 | 200-450 |
| 16 | 220-500 |
| 17 | 240-550 |
| 18 | 260-600 |
| 19 | 280-650 |
| 20 | 300-700 |
Please note that the values provided in the table are approximate ranges and may vary depending on specific system requirements and conditions. It is always recommended to consult with a professional HVAC engineer or technician for accurate duct sizing calculations based on the specific needs of your HVAC system.
4-Inch Rectangular Ducts Size Chart (60-330 CFM)
| 4″ Duct | 4″ CFM |
|---|---|
| 6×4 | 60 CFM |
| 8×4 | 90 CFM |
| 10×4 | 120 CFM |
| 12×4 | 150 CFM |
| 14×4 | 180 CFM |
| 16×4 | 210 CFM |
| 18×4 | 240 CFM |
| 20×4 | 270 CFM |
| 22×4 | 300 CFM |
| 24×4 | 330 CFM |
6-Inch Rectangular Ducts Size Chart (60-775 CFM)
| 6″ Duct | 6″ CFM |
|---|---|
| 4×6 | 60 CFM |
| 6×6 | 110 CFM |
| 8×6 | 160 CFM |
| 10×6 | 215 CFM |
| 12×6 | 270 CFM |
| 14×6 | 320 CFM |
| 16×6 | 375 CFM |
| 18×6 | 430 CFM |
| 20×6 | 490 CFM |
| 22×6 | 540 CFM |
| 24×6 | 600 CFM |
| 26×6 | 650 CFM |
| 28×6 | 710 CFM |
| 30×6 | 775 CFM |
8-Inch Rectangular Ducts Size Chart (90-1,500 CFM)
| 6″ Duct | 6″ CFM |
|---|---|
| 4×8 | 90 CFM |
| 6×8 | 160 CFM |
| 8×8 | 230 CFM |
| 10×8 | 310 CFM |
| 12×8 | 400 CFM |
| 14×8 | 490 CFM |
| 16×8 | 580 CFM |
| 18×8 | 670 CFM |
| 20×8 | 750 CFM |
| 22×8 | 840 CFM |
| 24×8 | 930 CFM |
| 26×8 | 1,020 CFM |
| 28×8 | 1,100 CFM |
| 30×8 | 1,200 CFM |
| 32×8 | 1,300 CFM |
| 34×8 | 1,400 CFM |
| 36×8 | 1,500 CFM |
10-Inch Rectangular Ducts Size Chart (120-2,350 CFM)
| 10″ Duct | 10″ CFM |
|---|---|
| 4×10 | 120 CFM |
| 6×10 | 215 CFM |
| 8×10 | 310 CFM |
| 10×10 | 430 CFM |
| 12×10 | 550 CFM |
| 14×10 | 670 CFM |
| 16×10 | 800 CFM |
| 18×10 | 930 CFM |
| 20×10 | 1,060 CFM |
| 22×10 | 1,200 CFM |
| 24×10 | 1,320 CFM |
| 26×10 | 1,430 CFM |
| 28×10 | 1,550 CFM |
| 30×10 | 1,670 CFM |
| 32×10 | 1,800 CFM |
| 34×10 | 1,930 CFM |
| 36×10 | 2,060 CFM |
| 38×10 | 2,200 CFM |
| 40×10 | 2,350 CFM |
12-Inch Rectangular Ducts Size Chart (150-3,050 CFM)
| 12″ Duct | 12″ CFM |
|---|---|
| 4×12 | 150 CFM |
| 6×12 | 270 CFM |
| 8×12 | 400 CFM |
| 10×12 | 550 CFM |
| 12×12 | 680 CFM |
| 14×12 | 800 CFM |
| 16×12 | 950 CFM |
| 18×12 | 1,100 CFM |
| 20×12 | 1,250 CFM |
| 22×12 | 1,400 CFM |
| 24×12 | 1,600 CFM |
| 26×12 | 1,750 CFM |
| 28×12 | 1,950 CFM |
| 30×12 | 2,150 CFM |
| 32×12 | 2,300 CFM |
| 34×12 | 2,450 CFM |
| 36×12 | 2,600 CFM |
| 38×12 | 2,750 CFM |
| 40×12 | 2,900 CFM |
| 42×12 | 3,050 CFM |
In summary, duct CFM charts play a critical role in HVAC system design and installation. Whether it’s for flex ducts or round ducts of various sizes, these charts provide essential information to ensure that the airflow capacity matches the system requirements. By utilizing the duct CFM chart as a reliable reference, professionals can make informed decisions and create efficient and effective ventilation systems.