How much heat will cfls create?

[herbtoker]

im about to start my first grow and bought some cfls just to get my plants started. im probably going to grow 6 to 8 plants in a starting box for 3 to 4 weeks, then move them all outside. i have 7 26 watt cfls and one 14 watter. im gonna start them in a box about 2 ft x 2 ft x 1 foot. i got a computer fan and wired it to my old phone charger. will that be enough air movement or will it still be super hot in there? thanks!

 

[dr.greenthumb85]

when you say a 2x2x1 box do you mean a grow box? or just a tray? if thats a grow box then yes its going to get way too hot in there.

 

[homegrownboy]

You need fresh air coming in as well as having the air inside the box drawn out. You would do best to have a fan blowing on the lights if at all possible...cfl's do get pretty hot if left with no fan cooling them...i would hate to imagine what 7 would do...probably in the high 90's, and that would be bad...you want to keep it at around 72-75.

 

[herbtoker]

yea its a box. its actually a little bigger, not much, maybe 2x2x2. hmmm... got any recommendations?

 

[herbtoker]

You need fresh air coming in as well as having the air inside the box drawn out. You would do best to have a fan blowing on the lights if at all possible...cfl's do get pretty hot if left with no fan cooling them...i would hate to imagine what 7 would do...probably in the high 90's, and that would be bad...you want to keep it at around 72-75.

ok thanks for the info...
what if i made an intake hole and then had the fan blowing on the lights from the intake hole, then had another hole for air to blow out of?

 

[homegrownboy]

Could work...but i wouldn't count on it. It would be best if you could put a few small computer fans inside the box below the lights...and have your exaust coming out the top of the box, that way the hot air will be blown up and out. Have the fresh air drawn in from the bottom of the box.

 

[dr.greenthumb85]

makes a big difference to add an exhaust and intake fan. just installed my 400w hps with one big box fan blowing on the ballast and plants the temps were still 85-90, with an exhaust fan pulling the warm air out the temp dropped back down to 77.

 

[herbtoker]

ok sounds good. i think i know what your saying... like this?

 

[herbtoker]

nevermind that didnt work. thats the biggest it would let me make it.
anyway... i think i know what your saying... so i dont need a fan blowing at the lights probably if i have one intake near the bottom and one exhaust near the top?

 

[homegrownboy]

Uhhhhhh?!?!?!?!?.....couldn't see it very well...lol, but i think you have it...you want to have an exaust fan at the top of your box sucking air out, and you want the fresh air being sucked in from the bottom.

 

[homegrownboy]

You DO want a fan blowing on the lights...hence why i said have a few computer fans at the bottom of the box blowing the air up, and the exaust fan at the top will be sucking out the hot air. The air intake should be near the bottom of the box as well, the cooler air coming in will help keep the heat down, the fans at the bottom of the box push the cool air up and the hot air from the lights gets sucked out with your exaust at the top.

 

[herbtoker]

awesome... thanks for the help. ill go pick up another fan and do a test run to see how things go!

 

[high2u2]

i currently am using CFL's in about a 2x2x3 box, i have a in the middle of the box with a fan infront of it blowing inwards towards the plants, plus i have a high power air purifier in there blowing on the lights and plants i forgot to make a exuast though. so my tempeture was pretty crazy today im going to put about 5 nice size holes at the top to let the hot air escape in a couple of hours, cant work on it right now so i just put a big tub of ice in there seems to drop it a few degrees, and im only running 4 32w cfls right now i have 8 but i turned half off when i saw the temp. i will let you know how it goes when i put the holes at the top.

 

[herbtoker]

i currently am using CFL's in about a 2x2x3 box, i have a in the middle of the box with a fan infront of it blowing inwards towards the plants, plus i have a high power air purifier in there blowing on the lights and plants i forgot to make a exuast though. so my tempeture was pretty crazy today im going to put about 5 nice size holes at the top to let the hot air escape in a couple of hours, cant work on it right now so i just put a big tub of ice in there seems to drop it a few degrees, and im only running 4 32w cfls right now i have 8 but i turned half off when i saw the temp. i will let you know how it goes when i put the holes at the top.

great, thanks high2u2. i started my grow 2 days ago and will officially turn the lights on tomorrow. i hope it all goes well. thanks for the help, let me know how it goes!