heat and venting

hi all ok so i have a growroom that is 2ft deep 3ft long and 5ft high im running 8 23watt cfls with hood that i made i put a 4 inch inline duct fan on top rear that vents outside 3 passive intake holes bottom front one 4 inch 2 3 inch and temps are still very high when doors are closed about 87 degrees to hot i think is that enough passive intake holes or do i need more the fan is 80 cfm no carbon filters just venting right outside and im going to order a 250 watt hps light this week for flower so how can i get temps down and will the hps run a little cooler than all those cfls and also with a room this size wiil 250 watt hps be good or 150 watt hps

"[FONT=Verdana,Arial,Helvetica][FONT=Verdana,Arial,Helvetica][FONT=Verdana,Arial,Helvetica][FONT=Verdana,Arial,Helvetica][FONT=Verdana,Arial,Helvetica]One additional note about intake ports - you will see much better results from your exhaust system if you install a second fan to create an active (as opposed to passive) intake system. Normally, when your exhaust fan sucks air out of your room, air is passively going to get sucked back into the room.[/FONT][/FONT][/FONT][/FONT][/FONT]"

Pasted from the link below and all growers should bookmark.


http://botanical.com/hydro/air/calculating_fan_requirements.html

I have a 2X2X5 box that i built. I also use cfl's for veg and hps for flower. I originally had a 4 inch fan for exhaust as well. However, it got too hot in the box. I was seeing temps in the 90's so I switched to the six inch fan (220 cfm). It dropped the temp but not enough. I found with the cfl i needed to have fans blowing directly on the lights so i got 4 pc fans and placed them around the box. Worked well to keep the temp around 84 but i was nervous for the hps. I bought a 150 W hps that had an option to buy a 4 inch vent flange for the top of the light. I split the 6 inch vent to two 4 inch vents and hooked one to the light and one just to the box. I also took a 80mm pc fan and it fits perfectly in the flange. The other pc fans point up to keep cool fresh air circulating to the top while one vents the light and a small desk fan cools the outside of the light. The other vent is hooked up to the top of the box. The temp in the box is 78-80. To me cfls are harder to keep cool as there is no separation between the light and plant. Its easier to vent an hps.
I tried every way i think i could and found this to be the best. I have avoided active intake because i use light tight air vents.
I think you could do the 250 w hps with the extra foot you have if you can directly vent it. It was a lot of work for me to get this right so i hope this can help.

wel i started by closeing 2 holes and a comp fan in one blowing in then removed 3 cfls temps went down to 84 lol but its pretty warm outside waiting till night time if alls good ill keep adding a light here and there and when hps comes hope it works ty

i will be having this problem as i found a craiglist deal for 400w n 200w but only one reflector and a vortex inline 6" fan for 200 and the dude said he'll hold it for a week for me. if it comes through for me i' was thinking of having a box fan blowing air inside from one side and the exhaust fan hooked up to a carbon filter blowing out the closet on the right side. my indoor temps stay 76 until winter when its probably 68-72 with a/c off. i'm hoping i can keep the optimal range without needing a bunch of extra shit. might invest in like 5 computer fans n just have them hanging next to the lights lol prob like 25 ducks for 4-5

different in a smaller spaced grow though so the venting principles are a little different.

yes but i still think the cfls throw more heat because you need many more to make up for lumens so it covers more space and with a hood almost the size of grow room harder to push the heat up i would think anyway

yes but i still think the cfls throw more heat because you need many more to make up for lumens so it covers more space and with a hood almost the size of grow room harder to push the heat up i would think anyway

lol srry about the dbl post

you might be ok its still pretty hot where i am what i did was close 2 passive holes put a comp fan for intake with my 4 inch for out take venting outside turned on a/c to remove some heat from house its off now and temps are stayind 75 at night and hitting about 80 tops during the day as the weather turns it should be ok im happy with my results sofar and ty all for input gl with your room wiselnfidel and also after some reading if it gets to hot with the hps try taking the reflector off they hold a lot of heat should cool it down if my temps rise again thats what im going to do ill post after light comes oh by the way my vanilla kush is like a healthy srub at the moment going on 4 weeks from seed 5 inches tall but about 14 inches wide with a root ball thats almost filling a 31/2 gallon pot cant wait