July 18, 2021
Use this calculator to determine the minimum air exchange required in cubic feet per minute (CFM). This calculation might be different at each stage of growth.
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Frequently Asked Questions
Why should I use this calculator?
Proper air exchange for growing weed is crucial for the health of your marijuana plants. Use this grow room air exchange calculator for growing marijuana. Use it to calculate the volume of air, in cubic feet, that must be moved around your marijuana grow room every minute. Use the results to decide the type and number of fans and filters to install in your grow room for optimal airflow.
Sign up for the Cannabis Growing Pro Certificate Program to learn more about cannabis grow room air exchange and buildout.
Does a marijuana grow room need fresh air?
Fresh air is crucial to your indoor cannabis grow room. It keeps the CO2 content at optimal levels for the plants and stops air stagnation that can attract pests and cause diseases.
Sign up for the Cannabis Growing Pro Certificate Program to learn more about air flow in your indoor marijuana grow room.
Will pumping CO2 into my grow room affect the fresh air?
Yes! Adding CO2 to your marijuana grow room will increase the air exchange for growing weed requirements, so you’ll need to use more fans. No worries, though! CTU’s air volume CFM calculator accounts for several grow room environmental factors, including CO2 enrichment, lighting, carbon filter use, outdoor temperature, and outdoor humidity.
Sign up for the Cannabis Growing Pro Certificate Program to learn more about how environmental conditions affect the airflow in your cannabis grow room.
What is CFM?
CFM stands for Cubic Feet per Minute. It is a measurement of the volume of air (in cubic feet) that a fan can move in one minute of time. CFM is the standard term of measurement used when talking about how much air exchange for growing weed is needed in a marijuana grow tent or cannabis grow room.
To learn more about CFM, sign up for the Cannabis Growing Pro Certificate Program.
How much air exchange does my cannabis grow room need?
Your fans should completely replace the air in your grow room at least every 5 minutes. For example, with a 5’ x 5’ x 5’ grow tent, you need to exchange 125 cubic feet of air every 5 minutes. The requirement increases when you add heat, CO2, humidity, or an air filter.
For more information on marijuana grow room air exchange for growing weed, sign up for the Cannabis Growing Pro Certificate Program.
How big of a fan do I need to buy for my grow room?
You need to install at least two fans in your marijuana grow room: an inlet fan to bring in fresh air and an exhaust fan to send out oxygen-depleted air. It’s also helpful to install one or more continuous horizontal air flow (HAF) fans to move the air in the room, providing enough circulation through the canopy to provide gas exchange for the cannabis plants.
To find the best air flow solution for your grow room, make sure that your fans provide optimal airflow as determined by this air volume CFM calculator. Divide the required CFM among all the fans you install.
For more information on grow room fan requirements, sign up for the Cannabis Growing Pro Certificate Program.
How does the cubic feet per minute calculator work?
The optimal CFM for your grow room is determined by the size of the cannabis grow room in cubic feet and several environmental factors. After calculating the basic CFM requirement based on the volume of your marijuana grow room using simple arithmetic, the cubic feet per minute calculator modifies that number based on the conditions in your marijuana grow room.
Sign up for the Cannabis Growing Pro Certificate Program to learn more about environmental conditions that affect cannabis grow room air exchange for growing weed.
What other equipment do I need to think about when it comes to a grow room air exchange calculator for growing marijuana? Carbon filters? CO2 machine?
Several environmental factors in and around your cannabis grow room can affect the optimal amount of air exchange for growing weed that you need, including CO2 enrichment, lighting, carbon filter use, outdoor temperature, and outdoor humidity. All those things are taken into account when you use this grow room air exchange calculator for growing marijuana.
Sign up for the Cannabis Growing Pro Certificate Program to learn more about how environmental conditions affect cannabis grow room airflow.
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