Air circulation

GanjaGreg.

Well-Known Member
So I was talking to a friend of mine about ventilating two small tents w one 200cfm exhaust fan. The conversation got around to controlling the room the tents were in instead of just the tents.. we discussed several different options and I was wondering if anyone on RIU could throw 2 cents in the pot. Here’s what I’m working with.

I don’t want to use an intake fan if I don’t have to.

200cfm 6inch in-line fan.
My house has an attic fan
The room is 10x15x10.
the room has two windows.
3 speed ceiling fan.
2x2x5 tent
3x3x6tent
I was wondering if I could ditch the exhaust fan all together and just leave the window facing my backyard open with the ceiling fan running. The. Cutting on my attic fan twice a day to flip the air in my house. Once in the morning, once at night. Or running the in-line fan through the two tents and out into the room with a window open and the ceilingfan circulating the air out..

ps!! My grow isn’t necessarily something I have to hide but I don’t want it to be to permanent in case I have to stop suddenly. And I don’t want ducting all through the room either.
 

Clumpyoyster

Well-Known Member
You will need fresh air in at the same rate as going out. Theres a way to figure out what cfm you will need in your fans in order to properly exchange the air in the room. If you dont you will end up with mold and mildew issues im sure. |Each tent will need to have an intake and an exhaust if you want to produce bud that is healthy. Why not draw air in from another room, cooler the better, or from outside if your climate allows, and exhaust the hot air from the tents through the windows via some vents and some plywood
 

420_Graze_It

Active Member
Are both tents flowering? Pulling air through 2 carbon filters is a lot of resistance for a single fan. It will definitely drop the CFM rating by a large order of magnitude permitted it doesn't fry. Keep in mind air is similar to water in that it will take the path of least resistance, so if one of your duct runs is much longer than the other, it will be taking most air out of the shorter run.
 

Clumpyoyster

Well-Known Member
Are both tents flowering? Pulling air through 2 carbon filters is a lot of resistance for a single fan. It will definitely drop the CFM rating by a large order of magnitude permitted it doesn't fry. Keep in mind air is similar to water in that it will take the path of least resistance, so if one of your duct runs is much longer than the other, it will be taking most air out of the shorter run.
like i said i would have four fans for those two tents intake fans on both and exhaust on both.
 

GanjaGreg.

Well-Known Member
The 2x2 is veg, the 3x3 is for flower.
I calculated my cfm by taking my cubic feet of the two tents . 2x2x5=20, 3x3x6=54. 20+54=74.
the room is 10x15x10=1500.
1500\200=7.5
So i think 200cfm would be plenty for the two tents. But it would take 7.5 minutes to flip the whole room with the 200cfm fan without the ceiling fan or the attic fan helping. And if I only have two 7 gallon plants in the 3x3 and two 4 gallon plants in the veg.. I don’t think I have to flip the air in the whole 1500cf every 1-3 minutes.. do I?
My thinking is if I keep fresh air in the room using a ceiling fan and open window 24/7, And the attic fan 2 times a day which will flip the whole house In less than a minute. I can just run the in-line fan through the two tents with ducting and open holes at the bottom to create passive intake, just to make sure the fresh air is circulating through the tents. @Clumpyoyster @420_Graze_It
 

shishkaboy

Well-Known Member
You can deffo vent both tents with one fan/filter combo....but if you do you prolly should just close the window and add an ac...

That what I do.
 

GanjaGreg.

Well-Known Member
You can deffo vent both tents with one fan/filter combo....but if you do you prolly should just close the window and add an ac...

That what I do.
Honestly I’m tired of spending money.. I’ve still got to upgrade my humidifier, my space heater, and when it gets warm again I’ll probably need a dehumidifier. I really want to take advantage of my attic fan I think it’s a really cool feature to my house that I can take advantage of I just gotta figure it out. How much did that thing cost you?
 

shishkaboy

Well-Known Member
My ac keeps my room at 75...

I have multiple tents hooked to one fan/ filter combo in that 75 degree room...

That's it...

I thought that's what you were talking about in your first post with the conversation you had...
 

GanjaGreg.

Well-Known Member
My ac keeps my room at 75...

I have multiple tents hooked to one fan/ filter combo in that 75 degree room...

That's it...

I thought that's what you were talking about in your first post with the conversation you had...
We are talking about the same thing I’m just trying to see where your FRESH air is coming from. Your ac unit is just recirculating the same air in your house, and I’m not sure on what exactly a carbon filter does, that’s why I asked.. does it purify the air or just get the smell out of it. Sorry if I’m being dumb, sometimes it takes me a minute to process stuff cause I wanna know all the ins and outs but once I get it I got it. I’m making sense to me lol
 

booms111

Well-Known Member
We are talking about the same thing I’m just trying to see where your FRESH air is coming from. Your ac unit is just recirculating the same air in your house, and I’m not sure on what exactly a carbon filter does, that’s why I asked.. does it purify the air or just get the smell out of it. Sorry if I’m being dumb, sometimes it takes me a minute to process stuff cause I wanna know all the ins and outs but once I get it I got it. I’m making sense to me lol
Few things. What lights are you using in each tent? What's the ambient temperature in the room the tents are going to be in? What brand is your exhaust fan(asking because you didn't know what shishka was showing in his picture).

You need exhaust in the tents otherwise the plants will condensate on the walls, humidity will go up and mold will happen.
 

GanjaGreg.

Well-Known Member
@booms111
I’m using a vivosun 300w led. actual watts 135. (Blurple). In the 3x3 which isn’t running yet btw, will have a 150watt sun system hps and a mars hydro ts1000 150 watts. The ambient temperature is 74 But I’m keeping a window open and the ceiling fan on w a space heater as a counterweight and canopy stays around 79 and 35%RH

alsowithout regulation my rh is like 25%!!! So I don’t think I’ll have to worry about mold until the season changes. I hope to be harvested by februrary:mrgreen:
 
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