blow in or suck out air??

B

beeznutz

Active Member
i jus set up a room at my new place, it's 8x7x6.5, and getting ready to go into flowering. i want to keep it sealed and id like to know if i could just use 1 fan for circulating air. this is happening in the basement, i'm in ohio, and it is pretty cold right now so i actually have to run a heater to keep the temp right also a humidifier to get that up cause it seems to be pretty dry.
what i have in the room right now:

1x1000hps
1xCoolmist Humidifier
1xHeater

at the moment i only have 2 haze growing with 15 clones coming soon.
so, because of temp being cold i'm concerned when i switch to 12/12 [im running 24/7 right now] it'll get pretty cold so i dont need a lot of circulation but i'm thinking i should be able to jus use one fan [i have a vortex 600 running at 465cfm and a vortex 800 @700cfm] to get it done.
my question, what's the best way around it? should i have the fan ouside the room with duct running on top of the growroom and suck the air out while having one or multiple 'holes' on the bottom of the growroom which i'm thinking it'll bring in fresh air.......or......have the fan blow in fresh air with one or multiple holes on top of the growroom to exhaust the air?

thx in advance....
 
Nubby Tubbs

Nubby Tubbs

New Member
pulling air thru an inline allows up to 4x more air flow...thats in cervantes bible. bends drastically decrease flow as well, but i have a few my hood vent.
 
g13hydo

g13hydo

Active Member
you should always be exauhsting more air then your have coming in

and id get fresh air in before your planned on exauhsting the stale air stale air can also lead to powdery mold

i pull air from my bedroom window which is pulled from a 6' 400cfm active air fan which cools both of my 600w hoods along with pulling fresh air in and a 8' 700cfm fan pulling air out
 
B

beeznutz

Active Member
k, cool- pull it is.....
jus having some holes on the bottom of the room should b enough then, for fresh air to b sucked in?
I'm not ready to set up the exhaust system to bring air from outside but my basement is pretty big , 35'x30 and I'm only using 8x7 for the grow room- is good enough fir now ?
 
cowasaki

cowasaki

Active Member
yeah ull be fine..put some holes in the bottom and exhaust the air out... show some pics of ur girls bro
 
FootClan

FootClan

Well-Known Member
beeznutz said:
i jus set up a room at my new place, it's 8x7x6.5, and getting ready to go into flowering. i want to keep it sealed and id like to know if i could just use 1 fan for circulating air. this is happening in the basement, i'm in ohio, and it is pretty cold right now so i actually have to run a heater to keep the temp right also a humidifier to get that up cause it seems to be pretty dry.
what i have in the room right now:

1x1000hps
1xCoolmist Humidifier
1xHeater

at the moment i only have 2 haze growing with 15 clones coming soon.
so, because of temp being cold i'm concerned when i switch to 12/12 [im running 24/7 right now] it'll get pretty cold so i dont need a lot of circulation but i'm thinking i should be able to jus use one fan [i have a vortex 600 running at 465cfm and a vortex 800 @700cfm] to get it done.
my question, what's the best way around it? should i have the fan ouside the room with duct running on top of the growroom and suck the air out while having one or multiple 'holes' on the bottom of the growroom which i'm thinking it'll bring in fresh air.......or......have the fan blow in fresh air with one or multiple holes on top of the growroom to exhaust the air?

thx in advance....
Click to expand...
you said you want your grow to be "sealed" as in a sealed grow? that would mean you wouldnt be bringing in air from outside becuase your grow room would be sealed off and you would need C02 supplement......Are you talking about something esle when you say "sealed" or "closed loop" just wondering little confused
 
greenkrakzak

greenkrakzak

Active Member
just remember, if your stems get weak tho, start to blow, it will help simulate the wind blowing the plant and strengthen the stem
 
B

beeznutz

Active Member
@footclan....yeah, I meant as a room, it's sealed from the elements and the surroundings..and I'm setting up the exhaust to bring inair then exhaust out...maybe I don't have the terminology right- wouldn't that be considered sealed?

@greenkrakzar.... I will have a rotating fan inside running 24/7 ;)

@cowasaky....yeah man, ill get some pix tonite.
 
FootClan

FootClan

Well-Known Member
beeznutz said:
@footclan....yeah, I meant as a room, it's sealed from the elements and the surroundings..and I'm setting up the exhaust to bring inair then exhaust out...maybe I don't have the terminology right- wouldn't that be considered sealed?

@greenkrakzar.... I will have a rotating fan inside running 24/7 ;)

@cowasaky....yeah man, ill get some pix tonite.
Click to expand...
as far i know it a sealed room means the same as a closed loop room....meaning the room is completly sealed off from the outside envierment......The only reason to bring in air in a sealed room would be as to cool your lights and that air wouldnt mix with the air inside the room...meaning you pull air from outside into ducting then past your light then back ouside never mixing with growiing envierment...but you are talking about bring in fresh air into your tent then exhausting it back out someplace else....thats not really sealed room becaue you have an exchange of air inside your growing envirment that came from another place....

So what you doing is just a normal grow not really sealed.......unless im missing somthing here....dosent really matter anyways just tryin to get on same page here...
 
Mr.Sativa

Mr.Sativa

Well-Known Member
Dude...if it's cold, you need to bring in air from the top of the room, because hot air rises. Pull air in from top, exhaust from bottom. I'd say it doesn't really matter where you put the fans, or if you use two fans for this...as long as you're doing this...you'll be fine. I'd use two fans...but that's just me...i like to overdue it a bit. You should have an oscillating fan in the grow room for plant sturdiness and basic in-room circulation, butttttt...that's kinda gonna mess up the airflow, depends on how big/powerful the OC fan is, that's why i'd use two of the same fans...for intake and for outake so you wouldn't have messed up airflow by OC fan. What i've normally seen is taking in and taking out the same amount of air, i don't know about exhausting more air than you put in, i don't know if that's possible...how would you put out more air than you're putting in? idk haha. But yea, i maybe wrong you never know, i'm actually gonna look this up!! g13hydo i'm not being an ass, id really like to know where you got this from! =)
 
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beeznutz

Active Member
thx, that clears it.... and makes sense.
def not gonna have co2 so my final plan is to have a fan blowing outside air thru the hood then blow back out and also another fan blowing fresh air in the room then exhaust thru filter and outta chimney. but I won't get there till it gets warm out, right now I just need air circulating thru the room.
I will have to play&monitor the room but what do u guys have ON during lights off? and do u think it'll b fine using the air from the basement to circulate?
 
FootClan

FootClan

Well-Known Member
Mr.Sativa said:
Dude...if it's cold, you need to bring in air from the top of the room, because hot air rises. Pull air in from top, exhaust from bottom. I'd say it doesn't really matter where you put the fans, or if you use two fans for this...as long as you're doing this...you'll be fine. I'd use two fans...but that's just me...i like to overdue it a bit. You should have an oscillating fan in the grow room for plant sturdiness and basic in-room circulation, butttttt...that's kinda gonna mess up the airflow, depends on how big/powerful the OC fan is, that's why i'd use two of the same fans...for intake and for outake so you wouldn't have messed up airflow by OC fan. What i've normally seen is taking in and taking out the same amount of air, i don't know about exhausting more air than you put in, i don't know if that's possible...how would you put out more air than you're putting in? idk haha. But yea, i maybe wrong you never know, i'm actually gonna look this up!! g13hydo i'm not being an ass, id really like to know where you got this from! =)
Click to expand...
i really doubt a ocilating fan inside your tent is going to mess up airflow into your filter.....
 
FootClan

FootClan

Well-Known Member
beeznutz said:
thx, that clears it.... and makes sense.
def not gonna have co2 so my final plan is to have a fan blowing outside air thru the hood then blow back out and also another fan blowing fresh air in the room then exhaust thru filter and outta chimney. but I won't get there till it gets warm out, right now I just need air circulating thru the room.
I will have to play&monitor the room but what do u guys have ON during lights off? and do u think it'll b fine using the air from the basement to circulate?
Click to expand...
so your going to have 3 inline fans??? one fan for dedicated light and hood?, one fan for intake? and one fan for exhaust?? thats seems just unnessary really and waste of money.......why not just two fans...one dedicated for light and hood and one for exhaust that is creating negative pressure... i dont get why you want to have an intake fan blowing air inside..the exhaust fan if big enough will suck hard enough to bring in fresh air though the passive vents at the bottom elimanating the need for the intake fan....
 
Mr.Sativa

Mr.Sativa

Well-Known Member
ok so the suck out more than take in is good...seems like it creates a negative pressure and ensures no smell leaks out of small cracks that every setup has. Since you'll be pulling more air out than in, you'll be pulling air from the small cracks and fissures...at least this dude ( http://forum.grasscity.com/grow-room-design-setup/465217-more-exhaust-more-intake-why.html ) explained it like this. About OC fans in the tent, i think it would uneven a passive exhaust as it's circulating air inside, but whatever, it doesn't really matter, you'd still have air coming in and out. I think footclan's right, having one exhaust fan capable of ensuring the negative pressure...is all you need! If i weren't using two fans for out/intake i'd just use a fan exhaust and passive intake!
 
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beeznutz

Active Member
footclan, thx for the input- I see what ur saying...I think I was thinking ahead, when it gets hot in the summer and by then I should have more lights in the room (I'm thinking 1x1000 in the middle and 4x200w cfl hanging in all four corners) ....
with that in mind, how would u set up the fan for the light?
suck from light out or blow in ? and would u have the hood sealed or opened?
also, is it really necesary to bring air from outside the house or would the air from the basement b fine?
 
g13hydo

g13hydo

Active Member
its hard to tell you what you should do without pictures. im not going to go on someones thread and advise them to do something thats not right. im just giving my opinion on whats worked for me as every situation is different. and i got that knowledge from years of experience.

fresh air is always better than stale air. as you will get into problems with mold and what not if your plants are too humid or vice versa. i would work on cooling you biggest light first. and always when cooling a hood you should have it sealed.blowing air to a light works better to cool it then sucking air from the light in my own opinion. also the less bends the better air flow. if your going to be using cfls you can use a oscilating fan to cool them. or a stationairy fan that just cools the cfls. cfls can be acouple inches away from the tops of plants as 1000whps would have to be atleast 18 inches to 48 inches away
 
LRGenius420

LRGenius420

Member
Ok If I were you... Id only get one good fan that is strong enough for that room... save money... I have a 5x5x6.5 and i only need the second to the cheapest inline fan from active air. I got a fan speedcontroller for 29 bucks, Than you need a fan that will pump air into your room from outside right, Whatever you do you want the airflow to be slightly more than what is going out of the tent, that way the tent stays slightly puffed up or full of air. if you are running co2, turn down the speed of your intake fan... turn off you exhaust and let it flow..
A tent will never be completely sealed unless you tape up the whole dame thing.
I hope this helps a few of you out :)
 
LRGenius420

LRGenius420

Member
I forgot to mention, split the intake fan and send 1 duct thru the light and out of the tent, and the other duct into the tent
 
FootClan

FootClan

Well-Known Member
g13hydo said:
its hard to tell you what you should do without pictures. im not going to go on someones thread and advise them to do something thats not right. im just giving my opinion on whats worked for me as every situation is different. and i got that knowledge from years of experience.

fresh air is always better than stale air. as you will get into problems with mold and what not if your plants are too humid or vice versa. i would work on cooling you biggest light first. and always when cooling a hood you should have it sealed.blowing air to a light works better to cool it then sucking air from the light in my own opinion. also the less bends the better air flow. if your going to be using cfls you can use a oscilating fan to cool them. or a stationairy fan that just cools the cfls. cfls can be acouple inches away from the tops of plants as 1000whps would have to be atleast 18 inches to 48 inches away
Click to expand...
Na its better to PULL air through the hood then push it out the backside........If you are planning on using a Carbon filter with a one fan set up then you will want to PULL the air through the filter then past the hood........The filter is designed to have air pulled through it not pushed through it......
 
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