Inline Fan CFM Calculator
Calculate the required CFM for your grow tent exhaust fan accounting for carbon filter and ducting losses.
Inputs
Results
Required CFM
150 CFM
How to Use This Calculator
- Enter your grow tent's interior length, width, and height in feet to calculate the room volume.
- Indicate whether you are using a carbon filter — filters add roughly 25% airflow resistance and require a more powerful fan.
- Enter your total ducting length in feet; longer runs increase static pressure and reduce effective CFM.
- Review the Required CFM to select an appropriately sized inline fan.
- Use the Recommended Fan Size (inches) and Est. Static Pressure (in WC) to match a fan's performance curve at your operating conditions.
How the result changes with Tent Length
| Tent Length | Required CFM |
|---|---|
| 3.9 | 147 CFM |
| 11 | 413 CFM |
| 20 | 750 CFM |
| 27 | 1,013 CFM |
What each input means
- Tent Length
- Interior length of your grow tent in feet.
- Tent Width
- Interior width of your grow tent in feet.
- Tent Height
- Interior height of your grow tent in feet.
- Carbon Filter
- Carbon filters add airflow resistance (~25%); factor this into fan sizing.
- Ducting Length
- Total length of flexible ducting — longer runs increase resistance.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersTent Length = 4, Tent Width = 4, Tent Height = 6, Carbon Filter = 1 = 5 input(s) provided
- Calculate Required CFMRequired CFM150 = 150
- Calculate Room VolumeRoom Volume96 = 96
- Calculate Recommended Fan SizeRecommended Fan Size4 = 4
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