Growroom Ventilation 1.5m

[stonedstump]

As some of you would know by now from my chatroom visits, I am getting the equipment together for my first grow.

 

I have a 1000w MH light which I will be putting into a plywood and panda film constructed room. The room will be 1.5m by 1.5m and 2.0m high. The room is located in the middle of a spare bedroom and will be 99% airtight and 100% light proof.

 

I have some questions about heat and ventilation if someone doesn't mind helping me out.

 

 

I am going to connect up 3m of black 250mm ducting to a 250mm 220L per second bathroom exhaust fan as my intake which will sit at the bottom of the room pushing air in between the two tubs. The ducting will run from a small open window to suck fresh air in.

 

(WILL 250mm DUCTING FIT A 250mm FAN OR DO I NEED 200mm DUCTING TO GO INSIDE THE COLLAR OF THE FAN?)

 

I then have another 250mm fan which I am going to mount in a hole cutout in my roof which will act as the exhaust fan. This will also run through 3m of black ducting to hole cutout in my growroom roof.

 

For my 18/6 light period I will run the light from 3pm to 9am I think will be best.

 

 

I also have an AC mounted in a window in this exact same spare bedroom, however I am unsure how to properly utilise this luxury. I have been told that if I run the AC in a sealed room the plants will die due to running out of c02.

 

I have TWO OPTIONS:

 

1) Run the 250mm fans like I described above and have no air con - WILL THIS KEEP MY ROOM COOL ENOUGH FOR DWC DO YOU THINK? Remember it is a 4.5cubic metre room 1.5m wide by 1.5m long by 2.0m high. The fans are rated to move roughly double that per minute.

 

OR

 

2) Should I connect ducting from the air con INTAKE which is on the front of the air con and then put the other end of the duct to my window and seal it so it sucks in fresh air as the intake. Then put another 3m duct running from the air con OUTPUT vent which is also on the front of the air con to the growroom?

[pipeman]

for a better answer you should tell us how hot that room gets.

 

ducting in fresh air from the outside as your intake and extracting the hot air back to outside is always the best option if its practical.

 

but you have to think about stealth. Are you renting? Will your neighbours think its sus that you have a vent running out of a window? Real estate agents are taught to look for things like that... It would also alert anyone who is familiar to growing in your area who might be tempted to have a look around inside when you're not home. I got a visit from the police once partly because I had a vent sticking out one of the windows (It had nothing to do with growing I was just running a portable airconditioner in my bedroom) But it goes to show how easily you can bring heat on yourself by giving out clues you are doing something unusual.

 

also, you have to think about blocking out light from that window. When you open your grow box that 1000watter will light up that room like you wouldn't believe even from the inside of the growbox and it will be very noticeable though any windows.

[stonedstump]

Hello there pipeman

 

I have no worries with regards to noise or renting or neighbours. I have put plywood over the two windows and cutout one small hole for the fan to sit in the room is totally light proofed.

 

I have no actually constructed the grow space yet though as I dont have the wooden frame and panda film yet (it's happening this week sometime).

 

That's why I am asking those questions up above there.

[jaguarrh]

gday stonedstump...

 

well, here is my 2 cents...

 

(WILL 250mm DUCTING FIT A 250mm FAN OR DO I NEED 200mm DUCTING TO GO INSIDE THE COLLAR OF THE FAN?)

 

well, i would say that if it is a standard style bathroom fan, it should have a plastic grill type affair on the front and would have a 250mm collar on the 'wall' side. it may not be a perfect fit as the fan may not be designed to accept ducting but you should be able to make the 250mm duct fit the fan with the aid of some duct tape. you can also use a stip of pandafilm as a kind of reducer or joining material for awkward connections.

 

I then have another 250mm fan which I am going to mount in a hole cutout in my roof which will act as the exhaust fan. This will also run through 3m of black ducting to hole cutout in my growroom roof.

 

this sounds to be a good solution for extraction if i am picturing it correctly. i would always keep the extraction going out of the grow room AND out of the bedroom it is within too.

 

I have TWO OPTIONS:

 

1) Run the 250mm fans like I described above and have no air con - WILL THIS KEEP MY ROOM COOL ENOUGH FOR DWC DO YOU THINK? Remember it is a 4.5cubic metre room 1.5m wide by 1.5m long by 2.0m high. The fans are rated to move roughly double that per minute.

 

OR

 

2) Should I connect ducting from the air con INTAKE which is on the front of the air con and then put the other end of the duct to my window and seal it so it sucks in fresh air as the intake. Then put another 3m duct running from the air con OUTPUT vent which is also on the front of the air con to the growroom?

 

as far as the AC goes. i would say, depending on your location and ambient temps, during the winter months the AC shouldn't be required. (certainly not where i am, its freezing) just bring cool fresh air in from the window as you have described (as long as the vent is stealthy of course) into your grow and exhaust out the hot air away from the bedroom.

 

if however the temps rise in the summer months, could you not just use the AC, in its standard mode, to cool the bedroom and then take air for the grow room directly from the bedrooms cooled air, instead of sucking in hot summer air for the grow from outside. essentially, if you can keep the temps in the bedroom at a sensible level, your exhaust fan should be able to keep up with removing the heat from the lamp and the grow.

 

i hope this makes some sense.

 

[stonedstump]

Yeah it did make sense actually because that is exactly what I thought of a couple hours after making this post

 

I thought, well I can setup the fans like I described then IF the temps get out of control I can turn on the air con and simply cool down the room that the actual growroom is constructed in.

 

I could then use a little 120mm fan to push the cool air in but the problem here is c02 levels I think. From what I can gather, the air con does not replenish c02 and unless the room has SOME sort of fresh air intake the plants will not like it much.

 

So maybe a little re-route of the ducting from the original window intake and then put it to the air con intake so it takes in fresh air from the outside and blows it into the room.

 

There we go problem solved... for now anyway

 

 

On a side note, has anyone ever actually grown in a 1.5m x 1.5m x 2.0m space with a 1000w MH light before?.. Anyone??

 

 

 

EDIT: BTW I love your signature jaguarrh, I think it is the single most wonderful quote ever spoken by any person in the history of the universe. I was going to copy it as my signature but I thought I better not

Edited July 19, 2006 by stonedstump

[pipeman]

you don't need any fancy ventilation setups for fresh air. If venting from outside to your growroom then to outside again is not enough to keep temps under control then you just turn your a/c on and disconnect your ducting from the window so it is now drawing in cooled air from the the airconditioner. Remember you still have the extraction fan going in your growbox which will create a negative pressure in the room and enough fresh air should seep in to keep your plants happy.

 

But really, you should find if you are ducting both your intake and exhaust fans to outside air you're not likely to need any additional cooling if you run your lights at night.