growbox 3'8" X 2' X 2' + HPS 250 + mylar = too hot

asaph

asaph

Well-Known Member
hello,

I have created a grow space in my closet - 3'8" high, with surface 2' X 2'. I installed to fans - 1 6" taking the air out (top of the closet) and on intake 4" at the bottom. see attached pictures. It's summertime now - outside temps are 85-95 at daytime, and the room temperature is regularly around 80 degrees F.

When I turned on the bulb and closed the space, fans on - temperature was about 92 - just a bit too hot. after coating the inside with mylar - the problem worsened reaching to the 100 F :\

Even with closet door open - it's not much better, temps may drop a couple degrees but not enough. I tried turning on the AC in my room (which is not practical since it's quite expensive to run - but i wanted to check) - also, not helpful - maybe 2-3 degrees.

The only way I could get the temp down to 85 - which is the threshold for growing was with an icebox (i put 4 small ice bags from the fridge in a pot and put in the closet with the intake fan aimed on it) , the closet door open and the AC turned on 65 degrees (the actual room temperature got to 75 - guess the AC isn't so good). But this is not practical.

My questions: How can I get the temperature to the good range? I don't have anymore money to put in a cooltube or that sort - just out of cash. I have too fans which cost a lot, they should be good enough - but they aren't. anybody has any more creative ideas?

another question - in winter time, when the room temperature can drop to around 60, will it be possible for me to cool it down? perhaps when the difference between inside the closet and the room will be greater, the ventilation would be more efficient?

another question - would installing the equipment in a big cardboard box (4' tall - 3'8"X2'10" surface) be easier? perhaps the cardboard breathes more and will not heat up to such an extent?

please, any answer would benefit me much. I have an outdoor plant starting to flower and i want it in there now (it only gets 4 hours of direct sunlight outside nowadays, and they're getting shorter).
 

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amnooneoo

amnooneoo

Active Member
I suggest making some sort of homeade light cooling.............. That is a must, IMO even with CFL. The whole idea is distance, coverage and penetration. I wouldn't move into a cardboard box, what u have is perfect.

One of the main issues i had, was SEALING the room with caulk, and using weatherstrip, making it as air tight as possible. Once you do that, you will eliminate light leaks as well. But, if air is drawing from leak points, your flow will not be as it should. Especially if your leaking really bad around your exhaust fan. Possibly moving your intake to the sides, IE. (2 smaller intakes on the sides). My intake was like that previously, but when I moved it like i just said, flow was better and temps dropped.

I assume there is a front door? More pix would help us.

Does the exhaust have a pipe that leads away from the grow? If it is purely an exhaust fan cut in, and a pipe for passive intake, your probably just making a big circle of hot air.

That is a VERY big light for that small space without a cool tube.
 
asaph

asaph

Well-Known Member
wow, thanks for the awesome reply man!

I have a silicone gun I can seal it with, from the corners... but the front door is indeed a problem - how will I seal that?
and - do you really think air-tighting would make a difference? It don't make sense to me, but I assume you know better.

I don't have a pipe for the exhaust - I'll try and get one (maybe i'll take from my laundry drier). I don't have a pipe for the intake either - it's just a fan. they're both blowing to and from the room, which is kinda hot (80 amibent).

Would vent holes in the sides rather than the backside be helpful? It won't be easy to open, this is full wood (not the fiber kind) and all I have is a regular driller.

Would a cooltube make a big difference? Can I be sure it will solve my problems? I can get it, but I need to know it will work for sure, I've spent so much money already. In your experience, does it drastically lower temps? also, what other equipment will I need, except for ductings? would the tube be compatible with my current bulb + socket + ballast connection? and the reflector? (see picture)?

The advantage of the cardboard box is that it's bigger (though not by much).

Really appreciate your answers, thanks.
 

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amnooneoo

amnooneoo

Active Member
Yeah, just get that exhaust a couple feet away from the box so your not circulating hot hair. Sealing it wont make a MAJOR difference, but may knock off a couple degrees.

Yeah, real wood would be hard to drill. Can you extend the intake further into the room? That would help a little. So air just isnt rushing in, and right up to the exhaust, and going around the plants and light.

A Cool tube will allow you to get the light much closer to the canopy, so yes. They are MOST helpful.

You can look for the "Pyrex Bake Around" cool tube in the DIY section. You can also use hurricane lamps (oil lamp) glass too, but its not as strong as pyrex.

Cooling your light should drop the temps majorly, its making all of the heat.
 
asaph

asaph

Well-Known Member
thanks!
i think i'm gonna get a cool tube. another question, after getting the cooltube - will i need to buy duct fans for it too? or will connecting a duct pipe to another hole in the backside suffice?

i was thinking this chain (starting and ending in holes in the back of the closet) - hole - duct pipe - cool tube 1 end - bulb - cool tube 2nd end - duct pipe - hole. perhaps i can get another fan for outtake or intake in one of the ends. what do you guys think?

thanks 1000 times!
 
R

rombomb420

Well-Known Member
asaph said:
hello,

I have created a grow space in my closet - 3'8" high, with surface 2' X 2'. I installed to fans - 1 6" taking the air out (top of the closet) and on intake 4" at the bottom. see attached pictures. It's summertime now - outside temps are 85-95 at daytime, and the room temperature is regularly around 80 degrees F.

When I turned on the bulb and closed the space, fans on - temperature was about 92 - just a bit too hot. after coating the inside with mylar - the problem worsened reaching to the 100 F :\

Even with closet door open - it's not much better, temps may drop a couple degrees but not enough. I tried turning on the AC in my room (which is not practical since it's quite expensive to run - but i wanted to check) - also, not helpful - maybe 2-3 degrees.

The only way I could get the temp down to 85 - which is the threshold for growing was with an icebox (i put 4 small ice bags from the fridge in a pot and put in the closet with the intake fan aimed on it) , the closet door open and the AC turned on 65 degrees (the actual room temperature got to 75 - guess the AC isn't so good). But this is not practical.

My questions: How can I get the temperature to the good range? I don't have anymore money to put in a cooltube or that sort - just out of cash. I have too fans which cost a lot, they should be good enough - but they aren't. anybody has any more creative ideas?

another question - in winter time, when the room temperature can drop to around 60, will it be possible for me to cool it down? perhaps when the difference between inside the closet and the room will be greater, the ventilation would be more efficient?

another question - would installing the equipment in a big cardboard box (4' tall - 3'8"X2'10" surface) be easier? perhaps the cardboard breathes more and will not heat up to such an extent?

please, any answer would benefit me much. I have an outdoor plant starting to flower and i want it in there now (it only gets 4 hours of direct sunlight outside nowadays, and they're getting shorter).
Click to expand...
I think the cardboard would be cooler. I really think your best bet is to build a sealed plexi glass heat shield directly under your light. That way the light & the plant are actually in separate chambers. Have separate exhaust systems for the lighting chamber & the plant chamber. Have your lower chamber intake on the floor & the exhaust at the top just under the plexi, then your light intake & exhaust at the highest possible point to (re)move the most hot hair.
 
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