Cold Air Ventilation

Little Tommy said:

It sounds good in theory. I am a little concerned about pulling arctic air through the hot lights. May cause the bulbs to shatter. I am not sure where the safety zone is for low end temperatures coming into the fixtures. The 2 HID lights should help with the cold temps though. Is the garage insulated?

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dbo24242 said:

how cold are u talking... I would just use the fan to pull air from the room and the HID heat out the roof and then control the intake w/ windowz and oscillating fanz

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SmokeDoggy said:

F the lights. If they aren't popping as is, don't bother cooling them.

COOL YOUR PLANTS INSTEAD!!

Cold air across Hot lights makes HOT AIR. Or at least WARM air.

Put the Cold Air at the bottom by the Roots and let it slowly flow up to the rest of the plant and THEN up to the lights and get hot. Sure the hot air up top will be hot still, but it's better than blowing now-hot air back down onto the plants.]


he's prob got inline hoods, air blows horizontally through them.... they are usually sealed and don't interact with the air around the plants. u could vent and suck air with 1 un-sealed hood, from around the opening and across the light 4 cooling, but not 2 in a row (no suction on the farthest light).

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ForbiddenFruit said:

Just built my room. It is 13'wide x 13'long x 9'high.

Going to run 2 x 1000watt HID's.

It gets cold here in the winter and the winters are long. So I am more concerned with cold than heat (at least 8 months out of the year).

My question is in regards to ventilation.

I have a few options, please tell me which is best.

#1 - Running cold air in directly from outside, BUT pulling it through both of my HID's. Which would serve a dual purpose in that it would warm the air going into the room AND it would cool off my lights.

#2 - Running the cold air into one end of my garage (where my grow room is located) and then pulling that air into my grow room on the opposite side of the garage. I'd have to buy an additional ventilation fan, but if this method is best/safest, then I don't mind doing so.

Also, if I went with option #1, I was thinking about using the ventilation system that is set up for the toilet in an adjacent and unused bathroom. This obviously leads through the attic and vents at the top of the roof. Only now I would be using this to pull air in, rather than sending air out. No real reason to do this other than the fact that it would be easy to do so, since it is already set up. Any unforeseen issue with my doing this?

As for exhaust. I was just going to send it all up into the attic. It's rather large up there and we have about 7 large vents on the roof. That should be OK, right?

thanks

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keeger123 said:

i'm gonna start a journal when i get my new room goin, i'm just putting the finishing touches on it...
- 8'x12'x9' room, completely polied and sealed
- 2 1000's with inline hoods (sealed of course)
- light mover on 6' rail
- 3 can fans, all 440 cfm (1 for intake, 1 for exhuast, and 1 for lights)
- pro filter 50
- Ebb & flow system with 18 individual buckets filled with hydroton, 50 gal drum, and flow controller unit

in the room, i removed the window and put plywood n insulation over the hole. then put an intake and exhaust vent through each side of the wood, and a little plywood deflector between the vents on the outside.
the intakes and exhaust r then Y'd inside, with backdraft dampners on each inlet/outlet of the Y's (4). 1 end or the intake Y goes to a fan then a boot for fresh air (it'll be on a cycle timer till i get my co2). the other end swings around the room to another fan, then into one end of the lights, connected in the middle, and out the otherside to 1 inlet of the exhaust Y. The other inlet of the exhaust Y is fed by my pro filter and the 3rd fan. that air definatetly has to go OUTSIDE!! not into an atic...

i live in the cold north, so i've thought alot about the cold winter air. for the extremes (Dec-Mar, Jul-Sept for heat), i'll probably cut another hole in the wall to the adjacent room for air intake. just make sure it has a fresh air supply and is fairly cool, not freezing, boiling

i'm definately more concerned with the cold than the heat here too, but the best way is just trial n error... if u want to cover that whole are, u'll be wanting to put ur lights on movers too, a 1000 only does a 4'x5' area

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stumps said:

I think Keeger is off a bit on how well a 1000w works ,but to each his own. I would duct air from out side to the lights. Then vent them to your outside room or to the inside of your grow room depending on temps in the grow room. unless your using a very strong fan the cool air will not hurt your lights at all. if the outside room stays 40 when cold I'll bet 2 1000w lights will warm that to 60. Without venting it would get much warmer but you need fresh air or a co2 setup.

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ForbiddenFruit said:

Well, I don't have any windows. But I am talking quite cold for at least 2-3 months. At least outdoors, but like I mentioned above, the garage stays quite warm.

However, if I pull outside air into the garage, it will no longer stay as warm in there. I do have insulation in my grow room as well though, so it should be manageable..Probably wouldn't drop below freezing even if I did not turn on the heater and had all power off in there. I hope, but then again I have never pulled in cold air like that before so I am not sure how much that insulation would help.

Either way, maybe I would be better off making use of that heated air from the HID's? At least in the winter time maybe? Then in the summer I could redirect it outside.

Keep in mind.. this is my 1st set up. SO I am not exactly sure just how much heat these things give off. I imagine quite a bit and I would hate to waste that in a time of need (winter).
thx

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ForbiddenFruit said:

Why do you think it to be a bad idea to vent into the attic? Or is that just your personal preference not to?

When using light movers, how do you connect the cooling ducts to them? Wouldnt all that back and forth movement wear them out pretty quickly?

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dbo24242 said:

Ok, if you have a damper on vents in the attic, you should exhaust the cooltube into the attic with a fan controller, so you can turn it down if you want more heat. That way you can even close the damper on the vents if its really cold and keep all the heat down there, but sounds like intaking and exhausting the HIDs into the attic is a good bet if you have other means of heat for the plants.

it will be better to not take air in from outside, but to exhaust it out the roof at a slower speed, that way you save heat and nrg and such, and if you run the lights at night it can help.

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keeger123 said:

Mildew n mold dude... that mold build-up u always here about is from the old stale moist air. try n get rid of it

use 6" ducting for ur lights that soft, really flexible stuff, leave enough slack on each end for horizontal and vertical movement. trial and error... u'll figure it out. attach it to the walls using big ass zip-ties in huge loops through a hole screw, so u can give ur hoses more or less slack as u move the lights. don't use that 'flex tubing' even though it sounds good. that just extends but doesnt move side to side very well. some of the softer flexible stuff is called flexy tubing too so watch out.

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ForbiddenFruit said:

So you don't think a 1000w will cover a 4x5 area? That sounds reasonable and about right to me, but I have zero experience and am only going by what I have read.

I will be using one 440CFM fan for both lights. Would you consider that to be "very strong"?

never too strong... but i think the 440's run at 1.2 A with 130 W of power on 120 V, so thats fairly high, but i'm using 3

As for the outside room staying 40... That is without pulling cold air into it. If it is 10 degrees outside and I have a 440CFM pulling that air in, then it won't be 40 in there for long. Still though, I guess it is best to pull into the garage 1st and then into the grow room... That seems to be the consensus/smart thing to do.

what about putting intake on a schedual? fill up the outer room with outside air for the desired time, then let it heat up a bit to almost room temp, then activate ur other fan to bring it in to the grow room. u could do this by putting fans on cycle timers. although, if ur other room is big enough and it had lots of air to supply, it would just be cheaper to always bring it in from there and not get a second fan/timer for outside air. just make sure u kick that old air outside through a carbon filter

As for a CO2 set up. What would you suggest for that and how much would it end up costing (rough estimate)? I guess I would be able to save a little by not having to set up an exhaust system to help offset whatever the CO2 would cost me.

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ForbiddenFruit said:

Yes, I will have other means of heating the room. I was just thinking that I could save that heat from the lamps rather than waste it. But if it is not wise to just let it loose directly into the room, then I wont do it. Guess I will have to experiment with it a bit.

So you are suggesting I take the air into the garage 1st, as a buffer, right? I still have to have fresh new air one way or the other (unless I get the CO2 running). It seems to me that a CO2 set up makes the most sense here.

If I use a CO2 unit I don't have to exhaust the room air at all, right? Just run a vent and inline fan for the lights and seal up the room entirely? Gotta go do me some reading on CO2.

thanks!

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