Heat Problems any comment would be appreciated

Discussion in 'Grow Room Design/Setup' started by UnderMe, Aug 12, 2011.

  1. Hello Grass City!
    I am new here to the forum just need some help from experienced people.

    I am not a newbie in the issue but I do have some questions in order to build a good room this time.

    My main problem in this set up is heat! I live in a place that is really hot and my test runs have marked temperatures of 95 during the warmer part of the day! So I am trying to focus on intake and outtake exhaust systems and etc.
    Here's my main question, I can't make any new holes or anything like that so I can't build an actual exhaust system getting fresh air so my idea is to attempt to get air from my room and just use the AC to cool the air there, however I don't know exactly how to exchange air without allowing any light to go through it. Is there any special screens that I could install on either side of the door so that each will have a big fan for in/out take. From what I researched I think people use screens similar to an AC screen to protect from any dust, but with another screen that blocks the light aswell.

    Also considerng the room is in my closet and the doors will have to be closed should I also attempt to build a small exhaust in using the crack under the door? I have read a little about people that did that, so my question is would it be worth it to attempt to build one w small tubes under the door, I could even go under the door and leave it right under the window so that I can leave it open some of the day

    Another quick question, I also feel like running the whole house AC all day only to cool down the closet is kind of a waste of energy. I was looking at some portable AC but I also found out they are very expensive and they do not cool down very much in contrast with an actual window AC. What are you guys' recommendations about that?

    Lastly but not least, I am going to be using a 600 MH/HPS bulbs BUT I do not have a cool reflector, mine is open. Is it going to be pretty much impossible to keep the temperature down w an open 600w HID? Also is it dangerous that the bulb would blow up on my face? And would the cool reflector protect me from that AND the temperature?

    Ok i think that is all my concerns please don't feel overwhelmed by so many questions, I just felt the need to put it all out there to read about different experiences. If anyone have any comments about it please I would love to read anyones solutions to my issues!

    Thanks GC
  2. First of all, get as many heat generating things away from the tent (and intake) as possible, like the ballast.

    Also, I'm not sure what you meant when you were talking about your exhaust... you need to be able to exhaust air efficiently (something like the volume of the room every five minutes) or you are wasting your time.

    A little more details about the exhaust / dimensions would be good
  3. #3 UnderMe, Aug 13, 2011
    Last edited by a moderator: Aug 13, 2011
    Thanks for your reply mduchonie

    Ok these are the dimensions that I can work with:

    5 feet x 5 feet and (9 feet of height)

    However I thought it would be better to make it a little smaller so that the plastic won't be getting stuck on the door so I was thinking to cut it at maybe 3 feet by the 5 feet wide.

    If you guys think I should just make it bigger let me know but with those dimension I calculated the CFM needed with the following formula (in the source I used to find this formula the guy was saying exchange air every 3 minutes so I just went with that to be safe):

    3' x 5' x 9'
    135 cubic feet

    Exchange air at least every 3 minutes

    135 / 3 = 45CFM

    *Each HID light adds 10-15% (if not air cooled)
    *Hot climates add 25%

    45 + 15%(6.75) + 25%(11.25) =

    63CFM required of ventilation

    I know there's a bit more to it in order to add each electronic that is inside the room but I am not sure about that yet so 63 sounds like a good number to start with and maybe I could get a few extra just to be safe

    Now here's my biggest concern on how could I even build this exhaust. I HAVE to close the closet door. That's a must, and I do not have any holes (besides the crack under the door) that I could use to make the exhaust. The problem with the actual air duct is that once passing the plastic that blocks the light it is just going to face the door and not be able to pump any air in(or out for instance). The only way that I could even imagine something like that working would be with a screen that I could put behind the door where I could face a few Fans to it (in & out), however this screen would have to block the light completely as well. I am using some thick black plastic to cover the door and block the light but this plastic allows NO air exchange at all and makes the inside very hot(during the day at least). How can I get around this? Is there any other way that would be more efficient? Any advice would be awesome
  4. #4 TBM, Aug 13, 2011
    Last edited by a moderator: Aug 13, 2011
    You are screwed. You have to have the closet doors shut and no room to run a duct. Plus if you don't seal the light leaks created by the doors, you will have hermies. Sounds like you have no option unless you build a cab or buy a tent. Your restrictions don't allow you to vent properly, so I wouldn't bother until you get that sorted out and pick a new grow spot.

    In that closet you don't really have an intake option unless you sealed it tight. You can passively intake from the bottom to bring in cool fresh air, and exhaust out the top somewhere. If you cannot drill because it is a rental, why not get new doors for the grow, then if/when you move you can put the old doors back on. If you cannot drill because of stealth reasons, you have bigger problems to worry about in the odor dept. Maybe think this one through a little more and get a good game plan down.

    I built a cab to fit inside my closet. I exhaust through a carbon filter and into the closet. Nothing comes in or out of the closet as far as ducting. I rely on the central air to keep things somewhat cool as well as opening the windows if the weather permits. I run the lights at night so I can have the closet doors open while I am home. During the day the closet stays closed and lights are off, so its not hot.

    Portable A/C units still generate heat, so they won't help much unless you run it away from the grow and duct the cool air to the grow.
  5. I know you said you couldn't cut the walls but here is the way I see it. Cut an exhaust hole to run ducting out of. Make sure to cut your hole about 3-4" below the ceiling making it harder for anyone to notice that you have cut through the wall because it is so far above eye level. Ideally the other side of where you are cutting would also be a closet so that both sides would be out of the way and harder to notice. The inside of your closet is probably white so that should make it easy when you move out, just patch your hole and slap some paint on it. Closets aren't known for their bright lights (unless you're on this website haha) so you will have that to your advantage. It would be really hard for someone to notice if it is up high, patched properly, poorly lit. I ran my exhaust this way, check out the thread in my sig if you'd like to see some pictures.

  6. Ya I believe you are right, i'm completely moving away from the portable A/C exactly because of that heat generated by it and besides the way I see it is that if I would spend that much money on something that is not even gonna cool that much or that it might even help heat up, then I might as well spend the money on a nice intake fan with some high CFM.

    However like I said in my last post, I am using some plastic to cover the space right in front of the door so inside of the plastic it gets pitch darkness with the lights off so that isn't my problem at this moment. I am starting to think that maybe if I cut the plastic and run a duct line going through the shelves that there is close to the ceiling I might be able to but a inline exhaust and still be able to pump some nice air from my room going through the door. So if that could work I would also make another in the bottom to pump air out of the room.

    Exactly like you said I plan on running my lights at night as well exactly for the same reason where I could leave the door open at night and close it during the day.
  7. I have to say that all the ideas I came up with which I wrote in my reply above were all after I saw your thread because you worked really well with the space you had so good job for that!

    The only problem with me when trying to apply your thread to my set up is that from what I understand you cut a hole on the wall but that wall was facing another closet in your own apt/house right? Because in my situation I have 3 walls that I could possibly cut. Two of them face the outside of the building which is also facing the parking lot where everyone walks by, so to drill a big hole for an exhaust system facing the outside of the building and my apt would be the only one having one of those holes and it seems like a bit too much attention that I do not need lol. The other wall does faces another closet, but it's my neighbor's closet, so I think he would wonder what is going on if I made that hole.

    So this leaves me with only 1 option that I can think of at the moment and it is the one I mentioned above. Maybe simply making a hole in the plastic and between the door and the plastic I would have 1 or 2 feet of space(depending how much I need) where I could install the ballast and in/out take duct fans. My only concern is, if I just make both duct lines, one in the top right corner and the other the bottom left, would it still be able to pump some nice air from my room to inside of the plastic, even if the doors are closed? By the way my closet has two doors that fold when you open them so even when it is closed there are many cracks top bottom and between the doors.

    Oh also I almost forgot going back to TBM I LOVE your idea of getting new doors for the closet because if I do need to modify the doors a lot in order to get some nice air in for the fans without getting charged extra when I move out then that is by far the best idea and I will totally consider it while I am planning it.

    One last question, those air ducts, do I have to know exactly how long I need them before I buy it, or is there a way to cut them to adjust it in size?

    Again thank you so much for the feedback, that gives me many ideas and I am planning on taking a few more weeks with the planning project only!

    I will also try to post some pictures as I go with the set up and see what you guys think of it

  8. Hmm, I see your problem and thanks for diggin my setup. I thought the door idea was genius as well although you'll need to figure out how to keep from exhausting out and your intake bringing that warm air right back in.

    As for the ducting you can pickup 25 feet of it at any Lowes or Home Depot and then cut it to your specific size. I think my 6" uninsulated 25feet was about $22.

    Oh and as for the doors on the closet you'll need to put something around the edges and cracks to make sure you have the light sealed out so your plants don't stress.
  9. You can build a light-trap for the exhaust and intake so that air flows through but light does not get in or out.

    If you can't cut the walls you can cut the door itself. If you need to keep that door intact then buy a cheap one at Home Depot or similar that is the same size, cut the holes in it, switch it out and store the original door, and then when you're done you can put the original door back on.

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