What Size Fan do I Need for 4x4 Grow Tent? Guide for Cannabis Growers
Growing Environment Volume — Calculate the volume of your room by multiplying the length x width x height. For example, if you have a grow tent that is 4' x 4' x 7', then the volume would be (4x4x7) = 112 cu./ft.
Volume To CFM — Your exhaust fan should be able to exhaust the equivalent of your growing environment’s volume in two minutes, or one minute if you are having issues with high temperatures. Assuming we are not having issues with heat, the growing environment volume from our example is 112 cu./ft., which means we need to exhaust 112cu.ft. / 2 minutes = 56 CFM. From this I know that I need a 56 CFM fan at minimum.
As you know, grow lights for weeds and pumps are the two obvious heat sources in a lamp. If you use air-cooled lights in your grow room, that’s a different case. But if they’re not air-cooled, you’ve to take each of them in calculating your estimated fan size. And same goes to other heat generative devices like motors etc.
For each 1000W lamp power, add ~10% to the fan cfm requirement.
If you have 4 fans of 1000W each, and if the generic calculations say a 200CFM, then the above total will be — Fan Size= (200 CFM + (200×40%))= 280 CFM
Why is Air Circulation Important?
When growing cannabis indoors, plants are normally in a relatively sealed environment without access to regular wind, whether plants grow in a closet, a tent or an room dedicated to growing. This can cause some problems compared to growing outside. Outside in ideal conditions there’s a breeze flowing through plants, giving them fresh air and strengthening stems. A steady supply of fresh air along with a breeze (not too much, not too little) helps cannabis grow faster and even protects plants against certain pests and molds.
What size carbon filter for a 4×4 tent?
In most cases, a 4 inch carbon filter will be more than enough for a 4×4 tent. Since a 4×4 grow tent has a relatively small internal volume a 4-inch carbon filter should easily remove all the odors from the air before they are exhausted from the tent.
If you plan on running an HPS (High-Pressure Sodium) light you might want to run a larger 6-inch carbon filter with a high CFM fan. In that scenario, you’ll need to vent a lot of excess heat, and you’ll need to get a larger carbon filter and fan to cool down the tent.
It’s also important to size your fan accordingly so the carbon filter operates at peak performance. For that reason it’s a good idea to get a carbon filter fan combo, so you can be sure that the carbon filter and fan will work together to keep odors from leaking out of the grow tent.
iPower 4 Inch 190 CFM Duct Inline Fan
This inline fan offers good and reliable service thanks to the advanced technology it was equipped with. When we say this we primarily mean the way it was designed. The particular design of the fan makes it so there is no noise or vibration once it’s turned on. What else contributes to the quiet operation is the permanently lubricated bearing. This means that it doesn’t require any maintenance to keep working its maximum potential.
What’s more, the fan is fluted on both sides which means it’s able to receive ducting. This also means that it’s for boosting the air flow in areas where there should be long runs of ducting.
Hydrofarm Active Air Inline Fans
Active Air is another well loved brand for inline fans in hydroponics. They offer 4″, 6″, 8″, 10″ and 12″ models, and this brand is known for their durability, simplicity and excellent design. The fans run quietly, are coated with a ceramic coating to prevent rust and degradation of the metal components, and include all necessary mounting brackets and hardware. If you are growing a large amount of cannabis and you want a professional-grade grow op, you need to get professional-quality equipment. Active Air inline fans definitely meet that requirement. Active Air’s fans do not come with a built-in speed adjuster, so you will need to purchase that separately. They sell one for $17 and if you order it at the same time as your fan, you will get free shipping.
Conclusion
Now that you are done reading this inline fan for weed guide, I hope that it is easier for you to make the right choice! With a well-designed and high-performing fan, ventilation in the grow room does not need to be a problem.