This video below will show you how to measure the airflow needed for your grow area.
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How to Calculate CFM for Your Growing Area:
Here’s what the formula looks like:
(Volume of Growing Area) x (Number of Air Exchanges per hour) / (60 Minutes) = CFM needed to fill your room with air or the amount of air your filter can handle at a time.
- To get the volume of your growing area, simply multiply the length x width x height.
- Take that number and multiply it by the number of air exchanges you want in your growing area.
- Air exchange is necessary to ensure all the air in your growing area is fresh. Even filtered air will eventually stagnate, so exchanging air is important.
- For most grow rooms, you’ll want to exchange your air about once every 3 to 5 minutes, or 12 to 20 times each hour.
- Take that number and divide it by 60 to get the minimum CFM your grow room needs.
- Now, take that number and multiply it by 2. This will give you a rough estimate of the true CFM requirements your grow room needs, taking into consideration pushing air through filters, the distance air needs to travel, grow room heat, and humidity.
- Once you have that number, find the fan that will give you what you need.
- Keep in mind you’ll have two sizes you’ll be looking at: the CFM and the diameter size of the duct opening (4in, 6in, 8in, 10in, and so on).