2400w Sealed Attic Contruction - Help

[PonicalChillin]

Hey all,

I've got some room in the attic and would like to put it to use.

I'm thinking 4 600w electronic lights over 2 3'x6' trays. I'd like to implement Co2 and totally seal the room.

I'm in a semi-finished attic in the northern hemisphere. It gets 90ish in the summer and down to the teens/singles sometimes in the winter. I'd like to be able to run this room year round.

I need some suggestions on sealing the room and such.
Here is rough design of the room in photoshop. It measures 10' in length and 8' wide.

Check out the diagram and let me know if this will work. Using a window ac could I build a false wall a foot or 2 away from the windows to mount the ac so that it is not seen from the outside? I would then leave the windows cracked open.

Is it necessary to aircool the lights too? If so how do you recommend I do that giving the particular diagram.

If necessary I could also eliminate the window ac and use a portable on the other side of the room. I think I could then pull cold air through the lights using the false wall/open window.

Check it out. Any help is appreciated/

In other words..how would you Pros out there setup in this room in the attic.
Thanks,

PC

 

[Guest]

I've never grown in an attic but trust me if you're going to use co2 enrichment,dont use a portable AC.Single or dual hose,it will rob your co2 I know this for absolutely sure.A good rule of thumb for non-cooled fixtures like the vertizontal fixture is 3-4 thousand BTU's per 1K light.I use a 12K BTU window unit in an 8 by 8 room with 3 vertizontals.I just thought I'd warn you about the portables and co2 enrichment,other than that they kick ass.I'd have no clue how to go about sealing up your attic though

 

[SouthernSmoker]

hey Ponicalchillin
The roomsounds great .just a few questions for ya .

How tall is the room ?

Do you have enough power running to the attic to run all that equipment ?

why are you conscerned about having a window unit in the room are ther not other houses in the area that run window ac units ?

How much space is left to the sides of your room behind the walls and above the cieling ?

Quote
Is it necessary to aircool the lights too? If so how do you recommend I do that giving the particular diagram.
QuotePonicalchillin


Air cooling your lights will make the room much more effeciant in the long run especialy if you are wanting to run C02.

 

[SouthernSmoker]

got to thinking about all i have read in the past two days and this would suit your needs very well .


click on pic to get full view
You would have to fit it to your room but it will allow you to run 2 600w in each room for 12hrs aday and only pull @ 12amps at a time to do it !

 

[Joe A. Grower]

got to thinking about all i have read in the past two days and this would suit your needs very well .

I see three problems with the setup you are suggesting SS,

1. You have a hole through the "ceiling" to vent the lights. This is an attic grow here. The "ceiling" in this case is the "roof," aka "what keeps the rain out of the house." I wouldn't want to put a hole in it if I didn't have to.

2. By venting you are losing the major benefit of A/C, which is the ability to effectively retain CO2. With the high amount of light he's talking about -- roughly 66 W/ft2 -- it would be a shame not to use CO2.

3. Obviously he can't stick the A/C out the window, or he wouldn't be talking about building a false wall and leaving the window open "only a crack." He's got neighbors with a view.

Alright, PC, here's the possibilities as I see 'em.

First, run it just like you have in your diagram, but the screw air cooling the lights. You are only looking at 2,400 W of light. The rule of thumb is 3,500 BTU/hrs of A/C per 1,000 W, so you are only looking at 8,400 BTU/hrs. Now personally, since it is in an attic, I'd bump that waaay up. Figure at least a 12K BTU A/C. A 15K or 16K model wouldn't hurt. They really aren't that expensive. Maybe $400 at most. You're going spend almost that much on each of your lights.

Now that's the simple way. If you really want to air cool those lights, you can. The only reason I could see for that is because you might want to get your lights down closer to your plants without burning. There's no reason to air cool just for heat control, since you can easily take care of that with A/C. To air cool, I'd take a 6" diameter insulated flexible duct from the window, through the wall and into the intake for light pair #1. Then take flexi duct from the output of pair #1, directly across to the other table, and into pair #2. The ducting would then go from pair #2 output, through the wall again, and out the window. Your going to need a couple of good centrifigul fans to pull the air your going to need to cool four lights.

In either case, you should seal the room and get a CO2 system. If you go with a propane burner instead of bottled CO2, you're going to need to upsize the AC some more to handle the extra heat.

In either scenario, you probably want to put a fan in one of the windows to exhaust the hot area behind the A/C to the outside. If you don't, temps are going to build up very high and drop the efficiency of your A/C pretty hard.

Good Luck!

 

[SouthernSmoker]

Hey Joe A grower good info

I am not sure how the house is built or the room for that matter He said it was a partially finished attic so i assumed it would have a space between the cieling and the roof . If not there are roof vents on most houses.

The Co2 can be set up and run with a controler where the fans will cut off and the room will be injected a few times aday they dont have to bath in Co2
all day to benefit form it .
A totally sealed room always sounds great but with out exhausting some of the hot air and smell atleast a couple times a day one leak and your home will reak with a grow this size especialy late in flower .An Ac will keep the air good for the room but will do nothing for the odor .

I dont think you would want to vent out the window either Hot steamy air pouring out a window will draw more attention than a Ac unit Imho.

 

[Joe A. Grower]

The Co2 can be set up and run with a controler where the fans will cut off and the room will be injected a few times aday they dont have to bath in Co2 all day to benefit form it .

Yeah, but you lose all your CO2 every time the fan turns on, and you have your CO2 levels bouncing up and down all day long. Plants really like it when the level is constant. They know the difference.

You can vent and use CO2, but just because you can DO it doesn't mean that it is to be DONE.

A totally sealed room always sounds great but with out exhausting some of the hot air and smell atleast a couple times a day one leak and your home will reak

That depends a lot on the strain. In any case, it is easily taken care of with a recirculating carbon filer. I used to use a filter I built out of a 5 gal bucket. The bucket has a fan on top and carbon held in place with window screen so that it contantly draws air in from the room, through the carbon, and back out into the room. Even a small filter can keep the smell from building up.

I dont think you would want to vent out the window either Hot steamy air pouring out a window will draw more attention than a Ac unit Imho.

Steam? Jesus, what kind of lights do you run? 5,000 W metal halides? I've never seen air come out of a 1,000W cooled hood much over 90F-100F. I suppose in the winter it could possibly have a visual signature (I've never seen this), but if that's the case, don't run it. If it is that cold outside you don't need to.

Have you actually SEEN a visible vapor come out of a light cooling exhaust, or are you talking out of your ass on this one?

 

[SouthernSmoker]

First off I never said the design was perfect ! It is just an Idea .
Since i have no specs on the room as far as electrical acsess I tried to keep amp draw down to as little as possible .
Running 2 fans and blowing them through the light would work best i do agree . But when you don't have the amps in the room and you are trying to make do with what you have a single fan drawing air will do the job . Or you could not go with air cooled hoods and let your ac do all the cooling for them as Joe said . I would suggest a filtered exhaust system for the room just incase of a system failure .

I also agree on the plant loving the constant Co2 but a 50lb tank will only go so far in trying to keep two rooms at 1500ppm at seperate times of the day .
Even a small Co2 generator ifeel would be overkill for a room this size . I'm not quite sure what equipment you would need to tone it down or to split it into two rooms . You will most likely need a dehumidifier aswell if you are going to seal the room off. Co2 can raise humidity to very high levels .

Good call on recirculating carbon scrubber . That would work well !

As far as talking out of my ass, since this is a discussion on how to help this man put together his grow room lets leave the smart ass comments out of it shall we !!!
And to answer your question Yea i have seen a 2000w grow room vented under a trailer and it looked like a dryer vent in the winter time .
Any sign of exhaust can bring unwanted attention to your grow !

 

[PonicalChillin]

Hey,

Thanks for the suggestion here.

The attic has 30amp feed in which I'd run the lights 240v..while running the other stuff 120v.

I did not want to have the AC visable for security reasons. My neighbors know I live alone and having an AC on the very top 3rd floor of a big house is iffy. I know.. I know.. that might be considered too PARANOID.. but at it takes is 1 person to notice something as simple as that doesn't "appear" normal. Running AC in the winter in a sealed setup also would be a big red flag aswell.

I do think excessive heat being exhausted out would be visable during the winter. Have you ever seen someone running a dryer in the winter? There IS visable "vapor". Its happens when hot air meets extremely cold air. Lets not argue that though..

I was considering the sealed room to actually make things easier since I will without a doubt need AC regardless (during the summer atleast).

After hearing some other suggestions and re-thinking what I'd like to do I might just toss a 4x8 Hydrohut up there in the middle of that space and call it a day using 2 1000w aircooled lights. Not seal the room, but guess I could toss an ac in come summer. Doing this would give me access all around the 4x8 space.

What do you guys think?
Can 2 1000w Lights yeild the same as 4 600w? The initial cost for the 1000w route would be significantly cheaper.

If I go that route I need to rethink a system as a 4x8 tray is out of the question due to size. I want something as simple and minimal as possible.

Water Culture system is not preferred as I do not want to deal with all the plumbing/water/air delivery/ res temp control..

I'm thinking either Ebb and Flow buckets (multiflow style) or top feed drip coco. Anyone know how Top Feed Coco performs in a recirculating system? I know it is commonly run to waste.

decisions..decisions.

peace,
pc

 

[Joe A. Grower]

The attic has 30amp feed in which I'd run the lights 240v..while running the other stuff 120v.

More than enough. Your lights are only going to pull around 11-12 A off that 30A circuit. The AC will probably take another 6-8A. That's plenty of headroom.

I was considering the sealed room to actually make things easier since I will without a doubt need AC regardless (during the summer atleast).

A sealed room is not only easier to design, it is more secure and more productive. It may also be the less expensive route. Non-cooled light fixtures are cheaper than air cooled and you won't need to buy the pricey fans you'll need to shove air through all that ducting. I think you just ought to skip the air cooling and size your AC to deal with all your heat needs.

Can 2 1000w Lights yeild the same as 4 600w? The initial cost for the 1000w route would be significantly cheaper.

Nope. The 4 600's not only have a significant lumen advantage, they also pick up the "multi light bonus." Light hitting a plant from multiple directions seems to get absorbed better. That being said, two 1000W lights will still yeild reasonably close to the 4 600 W. If you have the cash, go with the 600's.

I want something as simple and minimal as possible.

I don't think you can beat ebb and flow for simplicity, ease of construction and reliability. You can make your own system with some big tubs. Just fill them with hydroton, or lava rock, or gravel, or whatever inert material you happen to have handy. Add a pump, a resevoir, a standard mechanical light timer, and very little plumbing, and you got grow!