Inline Booster Fan - Worth a Try?

vtguitar88

Well-Known Member
A fan is not a way to control temperatures.
How do you figure? Clearly, it’s not the same as refrigeration. But if I’m only concerned with temps in one particular area, and I use an extraction fan to direct the hot air away from that area, I thereby control temperatures in the area in question. The setting of my variable fan speed controller directly correlates to the temperature in my tent.

Some more details about my setup: I have an absolutely massive basement, and used double-layer moving blankets to wall off an approximately 15x25 area, which includes one small window to the backyard. Currently, I’m exhausting both tents upward toward the ceiling but still within the “room,” because the ambient temps in the basement are only about 56 this time of year otherwise. My temps in both tents top out at about 79. I did experiment with sending the exhaust out into the rest of the basement, and that greatly reduces the temp differential between the grow area and the remainder of the basement. So I know my moving blankets are functioning as a significant thermal insulator/barrier. I also have the option to exhaust out the window through a solid piece of fiberglass insulation I retrofitted with two removable 6-in ports. I will most likely begin doing this as the external temps increase in spring. So essentially, each tent can pull from and/or exhaust to three different areas: the walled off grow area, the larger basement area, and outside. By using fans to move air to and from these distinct areas, I’m able to exert a good deal of control over the temperatures.
 

vtguitar88

Well-Known Member
I don’t have to make any decisions just yet, but come late April we’ll start having some warm enough days that I may have to make some changes. I’ll probably give the booster fan a try at that point, and let you guys know how that goes. Thanks again for the helpful discussion
 

brewbeer

Well-Known Member
One fan per light, keep ducts short and rigid. Fan cfm ratings need to be derated based on ducting length and type, which can be substantial. Air condition the room.
 

Beachwalker

Well-Known Member
Many thanks for all the thoughts here guys! I’m inclined to agree with gjs, simply because adding the booster fan costs 20 bucks and minimal effort. Not much to lose. I did wonder if the different CFM ratings could create some kind of pressure relationship that would put additional strain on one or both fans, which Projectinfo alluded to....

Seems like people may have (understandably) missed a detail in my long initial post - I do technically have one 6-inch fan per light in my tent! It’s just one directly cools both sealed hoods with air that never touches the grow room, and the other scrubs the air from the tent through a carbon filter. I have variable speed controllers on both of these centrifugal fans. The room exhaust fan with the carbon filter definitely aids a lot in cooling, but I generally feel like I need less power there and more CFM directly cooling the hoods. I usually have the fan with the filter at half power and the one cooling the hoods at full blast. So if I added another 6-inch fan to this tent, that would make three 6-inch centrif fans for two 1k lights...

Another option would be to just direct-cool the first light (so pull cool air into the tent, push through that sealed hood and directly out), and connect the second fan with the filter to the second hood. In that case, I would need to run the first fan at a lower power than the fan with the filter, but I have two variable speed controllers so that would be easy. That solution would be free - do you guys think that would work better than the duct booster? Thanks again for helping out a fellow potanist.

If I'm understanding your two lights are in line with one fan, so the carbon filter fan wouldn't really affect overall cooling much, if at all.

Did I miss why you don't want to add an air conditioner ?

The only small tweak I would make is use the fan to pull, mount on the outside of the second tent or light, put the carbon filter as high as possible to take the hottest air out (that could make a few degrees difference right there) ..and an air conditioner was mentioned a few times in the thread
-good luck
 
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