CFM Calculator
INCREDIGROW GARDEN CENTRE
CFM Calculator
Calculate the airflow you need for your grow tent, room, or enclosure. Enter your dimensions, choose your air exchange rate, and account for real-world resistance like filters, ducting, bends, and heat load.
What airflow do you actually want?
Grow tents and grow rooms
• 1 exchange per minute: baseline for small tents with LED and mild conditions.
• 2 exchanges per minute: common real-world range.
• 3-4 exchanges per minute: hot rooms, strong lighting, or heavy odour control.
Other uses
• 3D printer enclosure (PLA): 0.5–1 exchanges/minute
• 3D printer enclosure (ABS/resin): 2–4 exchanges/minute
• Kitchen smells: 3-4 exchanges/minute
• Bathroom: 3-4 exchanges/minute
• General odour control: 1–2 exchanges/minute
How this calculator adjusts:
• Carbon filter: +10% to +75% depending on restriction
• Ducting: +1% per foot
• Bends: +15% per 90° bend
• Heat load: +10% to +40%
• 1 exchange per minute: baseline for small tents with LED and mild conditions.
• 2 exchanges per minute: common real-world range.
• 3-4 exchanges per minute: hot rooms, strong lighting, or heavy odour control.
Other uses
• 3D printer enclosure (PLA): 0.5–1 exchanges/minute
• 3D printer enclosure (ABS/resin): 2–4 exchanges/minute
• Kitchen smells: 3-4 exchanges/minute
• Bathroom: 3-4 exchanges/minute
• General odour control: 1–2 exchanges/minute
How this calculator adjusts:
• Carbon filter: +10% to +75% depending on restriction
• Ducting: +1% per foot
• Bends: +15% per 90° bend
• Heat load: +10% to +40%
Filter Size & Performance
Bigger filters restrict airflow less. A larger diameter or longer filter gives air more surface area to pass through, which lowers resistance and improves overall performance.
Smaller filters or compact designs restrict airflow more because the same volume of air is forced through a tighter space. This increases static pressure and reduces real-world CFM.
Thicker carbon walls improve odour removal by increasing contact time, but they also increase resistance. Thin filters flow more air but can struggle with strong smells if airflow is too high.
A carbon filter’s CFM rating is the maximum airflow it can effectively clean, not the airflow you will actually get. Filters add resistance, which reduces real fan performance. Your filter should be rated for at least the same CFM as your fan, but larger filters generally perform better by reducing restriction and improving odour control.
If noise is a concern, consider using a larger fan with a built-in or separate speed controller. Running a bigger fan at a lower speed is typically quieter and more efficient than running a smaller fan at full power.
Smaller filters or compact designs restrict airflow more because the same volume of air is forced through a tighter space. This increases static pressure and reduces real-world CFM.
Thicker carbon walls improve odour removal by increasing contact time, but they also increase resistance. Thin filters flow more air but can struggle with strong smells if airflow is too high.
A carbon filter’s CFM rating is the maximum airflow it can effectively clean, not the airflow you will actually get. Filters add resistance, which reduces real fan performance. Your filter should be rated for at least the same CFM as your fan, but larger filters generally perform better by reducing restriction and improving odour control.
If noise is a concern, consider using a larger fan with a built-in or separate speed controller. Running a bigger fan at a lower speed is typically quieter and more efficient than running a smaller fan at full power.