New - Growbox and Heat issue

Discussion in 'Grow Room Design/Setup' started by Slypknow, Apr 5, 2006.

  1. Hey mates!

    Have a slight issue with the heat in my grow room.

    C25 Box (extended its depth using 1x2's) so now 4ft x 4ft x 7ft
    400w HPS light
    100-120cfm squirrel fan for exhaust
    using tempered glass in light to reduce heat
    have fan hooked up to light using duct and exhausting heat through top of box
    Drilled 5 holes in bottom of box to allow cold, fresh air to enter (negative suction from exhaust)

    When I first turn this puppy on I'm sitting at around 78F

    After about 12 hours the temp in the box has increased to 90-94F !!!

    I'm new to the whole indoor growing - so here is what I think is going on. When the box is turned on the air in the room is cooler. As time goes on the exhausted air (from top of box) is heating up the air in the room (just have it sitting in a bedroom).

    Here's my problem. This is a stealth box and is light tight. I am trying to figure out a way to expel the hot air from the box without heating up the room to 90F but without making it seriously obvious. If I were to hook a duct up to the exhaust fan and put a hole through my ceiling, the heat could vent into the attic - but this is FAR from stealthy.

    Shit, right now just the fact that this room is heating to 90F is blowing my stealthiness.

    Anyone have any ideas? I thought about a box fan sitting on the floor in the doorway just to move the air out, but again - not very stealthy... :(

    Any help is appreciated!!!

  2. I think that you should pick up a few muffin fans about 120cfm and hook them up at the top of your box to help keep moving. also how big are you intake holes at the bottom. Can you post a picture of your intake holes?
  3. The intake holes on the bottom were made using a drill. I used a 1/2inch bit and drilled 5 holes in the bottom. I then cut out about a 2inch square in a corner to allow power cords to go through. Directly above the 2inch square I have a horizontal rotating fan (tower) so that's blowing the cooler air around.

    The most perplexing part of all this is I originally made my own box out of plywood. The box wasnt sealed very well and had a huge intake hole in the side of it (about 4inch diameter). This box ran around 80F nonstop.

    When I switched to the C25 it was sealed WAY better yet seemed to increase in temp quite a bit. The squirrel exhaust fan is blowing quite a bit of hot air out, so I imagine the intakes are fine for pulling air in....otherwise the output would be reduced.

    One other thing I changed was I put the ballist into the box (the C25 had plenty of room for it) instead of my previous setup where I had the ballist on top of the unit. I'm going to try moving it outside of the box to see if that reduces the heat generated inside and overall temp.

    I'm not sure if adding another intake and making it larger would help much considering again the output of the exhaust fan doesnt seem to be restricted.

  4. take out the ballast. I still don't think you have enough intake.
  5. Welp amazingly the simple science of 'GET ANYTHING THAT GENERATES HEAT OUT OF THE BOX' actually worked! hahaha.... some days I'm such a dumb ass.

    Removed the ballist and bingo, temp dropped 5-10 degrees within the first 30mins. Luckily for me my hydro store will also allow me to trade up - so I'm going to swap this 130cfm exhaust cage fan for either a 400 or 600cfm one (to prep for when I have to add a carbon scrubber to the mix).

    These fans are showing as moving 3000sqft of air in 1minute - my box is only 60sqft (approx) so it should be interesting. Hope the new fans dont just lift my plants off the ground and suck em up into the exhaust.... hahaha


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