Fan placement, help appreciated.

D

Destroyer of chairs

Well-Known Member
I want efficient cooling and mixing of the air.
Where would u place fans?
Were thinking one in the middle of the room at the floor, blowing straight up to an oscillating fan(allready installed) cooling the lights and generally moving air around. My extract fan regularly turns up to 100% from 20% when temp reaches limit, so alot of movement around the intake when lights on.
Guess I would need one fan to move the air below canopy on the side of the room with no intake?
This is all suggestions and will happily change my setup for a better one.

Room is 3x1.3m and about 2.3m heigh.
Growing areas about 1.2x1m each side.
Intake bottom corner and exhaust top corner opposite side and powered by a 100w 800m3/h fan pulling air through a carbon filter.
3x240w qb each area(6 total).

What else Info do u need? Ask :)
A couple pics of the room. Not current date but they were the only I had.
IMG_20201222_114301.jpgIMG_20201225_182434.jpg
 
I dont run an intake fan you shouldn’t need to in that size room. Just use a length of ducting in the intake hole ideally coming up through the floor even more ideally drawing cool air from under the house if possible. The exhaust fan will pull the cool air up as it pushes the hot air out from above the light. My room is a lot bigger than yours but I always have oscillating fans on the ground blowing up & through to the canopy as you say. & I use clip fans on the walls blowing each wall at an angle which kinda creates a vortex & keeps all the air in the room moving around all the time without blowing directly at any parts of any plant. The leaves gently flutter no stress
 
Darkoh69 said:
Just use a length of ducting in the intake hole ideally coming up through the floor even more ideally drawing cool air from under the house if possible.
Click to expand...
Filtration is highly advisable if grabbing air from outside.

I like to have fans moving air between the lights and canopy. This might be difficult in your space.

A good exhaust system grabbing hot air up high and blowing it out with passive intakes down low for makeup air to flow in will help keep air moving from bottom to top, this helps prevent any high RH% microclimates from forming down below the canopy where powdery mildew likes to first take hold.
 
Darkoh69 said:
I dont run an intake fan you shouldn’t need to in that size room. Just use a length of ducting in the intake hole ideally coming up through the floor even more ideally drawing cool air from under the house if possible. The exhaust fan will pull the cool air up as it pushes the hot air out from above the light. My room is a lot bigger than yours but I always have oscillating fans on the ground blowing up & through to the canopy as you say. & I use clip fans on the walls blowing each wall at an angle which kinda creates a vortex & keeps all the air in the room moving around all the time without blowing directly at any parts of any plant. The leaves gently flutter no stress
Click to expand...
Yes, I figured with my fan there is no need in that space for active intake.
I do not have the option to draw from straight outside it would freeze my room. At least with how it's set up right now.
I don't have a heater in my flower room, it relies on lights for day warmth and oil oven in the next room for night warmth(and up until now before it dropped to 10f it worked great).
I hijacked my exhaust with a pipe that let some hot air back to the other room.
What I'm trying to say is winter is tough here and I need that "lounge" room to heat up that ice cold winter air before entering the room as I don't want a heater in there if possible.

BTW I didn't mean to blow through the canopy, but have a floor fan between growing sections, and blow cold air fast and hard to the top to even any ° difference in the room. Maybe this is not something to shoot for? I dunno, with the less than perfect insulated box I am feeling a draft when all is off but mainly just cold air falling from around the exhaust tubing through the roof.

I can grab a few pics of current fan setup in a bit when I feed. I recently discovered the trick to blow at walls :D
 
Renfro said:
Filtration is highly advisable if grabbing air from outside.

I like to have fans moving air between the lights and canopy. This might be difficult in your space.

A good exhaust system grabbing hot air up high and blowing it out with passive intakes down low for makeup air to flow in will help keep air moving from bottom to top, this helps prevent any high RH% microclimates from forming down below the canopy where powdery mildew likes to first take hold.
Click to expand...
What minimum filtration is that? I'm asking cause I am indeed pulling air from underneath, but in the other room.
I currently using double layered bug netting :'D

Do u feel the need to move the air between light and canopy when using leds as well? Wanted to do this but not sure how. I currently only have fans below canopy and top of lights.
 
Your doing alright mate. It doesn’t need to be complicated as long as you get the fundamentals. Im from New Zealand Its hard for me to get my head around having to warm a grow room. Ive probably seen snow up close 5 times in my life
 
Darkoh69 said:
Your doing alright mate. It doesn’t need to be complicated as long as you get the fundamentals. Im from New Zealand Its hard for me to get my head around having to warm a grow room. Ive probably seen snow up close 5 times in my life
Click to expand...
Thx for the kind words.
New Zealand, hell alot of sheep's there right? Scandinavian, I envy ur climate.. The town next to my hometown gets insane cold in winter. Drops as low as -58°f at worst. I moved south though and will probably not go lower than -4°f.
What can I say, I like to complicate things. Its in my nature hah..
 
Btw here is he room. Only wall not taken picture of is all clean nothing on it.
As u can see I have the big 45cm 45w at head/light level oscillating on 2/3 power with a ever so slightly(1 click from straight) downward angle. Doesn't seem to hit my plants but force the warm air a bit down to mix with the cold. If I had a floor fan pointing straight up I wouldn't feel the need for this and would just straight them up.

The one below is prob not more than 25w and just something a friend gave me. It does oscillate and set in on max power blowing air against the wall.
IMG_20210107_141737.jpgIMG_20210107_141733.jpg
IMG_20210107_141659.jpgIMG_20210107_141651.jpg
 
I would get a tower fan and hang it on its side, so it blows a carpet of air just over your canopy. I just got one for my tent and love it...there are pics in other threads of people doing the same thing.
 
Rurumo said:
I would get a tower fan and hang it on its side, so it blows a carpet of air just over your canopy. I just got one for my tent and love it...there are pics in other threads of people doing the same thing.
Click to expand...
This sounds amazing! This way I can have a breeze between light and canopy, thx:)
Edit: exactly where would u hang it? Middle or ends? Maybe one middle one at the start? Both blowing direction of exhaust?
 
I would just try one to start, I have a 42 inch Lasko tower on one side of my 4x4 and it really moves the air across the top of the canopy! So just try one to begin with and just see which position you like better before putting it up permanently.
 
Destroyer of chairs said:
Thx for the kind words.
New Zealand, hell alot of sheep's there right? Scandinavian, I envy ur climate.. The town next to my hometown gets insane cold in winter. Drops as low as -58°f at worst. I moved south though and will probably not go lower than -4°f.
What can I say, I like to complicate things. Its in my nature hah..
Click to expand...
Probably more Chinese people here than sheep nowadays;-)
 
Destroyer of chairs said:
What minimum filtration is that? I'm asking cause I am indeed pulling air from underneath, but in the other room.
I currently using double layered bug netting :'D

Do u feel the need to move the air between light and canopy when using leds as well? Wanted to do this but not sure how. I currently only have fans below canopy and top of lights.
Click to expand...
If you want a filter that will get everything then a dust shroom is the way to go. When it's dirty toss it in the washing machine and then recoat with oil.
 
It might not affect you the same if you don't use a screen but it's worth mentioning.
I normally use a screen or net so I have two distinct climate zones above the canopy and below the canopy.

With the cool air coming in the bottom vents it's easy to chill the pot area below while maintaining a nice canopy temperature above, ime you need to have warm air getting pushed down under the canopy, of course its all relevant to the air temperature coming in it might not affect you but I need 12/13c to maintain 20c below 25c above any colder is an expense.

Next year I'm stopping for the winter it's to expensive.
 
Star Dog said:
It might not affect you the same if you don't use a screen but it's worth mentioning.
I normally use a screen or net so I have two distinct climate zones above the canopy and below the canopy.

With the cool air coming in the bottom vents it's easy to chill the pot area below while maintaining a nice canopy temperature above, ime you need to have warm air getting pushed down under the canopy, of course its all relevant to the air temperature coming in it might not affect you but I need 12/13c to maintain 20c below 25c above any colder is an expense.

Next year I'm stopping for the winter it's to expensive.
Click to expand...
Omg I forgot my fan set up in a 5x5 ... I've got two pieces of ducting from the inlets facing the back of my oscillating fan, the oscillating fan blows over the canopy and across the bulb (parabolic) the parabolic diverts the air down under the canopy, depending on the season I sometimes have a 2nd fan under the canopy to accelerate the air getting pushed down under.
I can maintain 25/26c during the summer using around 30% power of my 6" rvk

I've got variac with 3 taps taken of the main rail, a 4/8 and 12w to select from.
I've got the taps wired to one side of a 2 stage relay via a selector switch and the main variable dial wired to the other side of the relay, so when it heats above x it cools then switches to an idle speed so essentially it is constantly pulling fresh air.

I've likely made that sound complicated, it isn't if you're confident with electricity I don't have any experience beyond grow room stuff.
 
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