Need advice cooling off a 600w light.

Hello everyone. I have a spare room that is approximately 6.5' x 6.5' x 7.5' with one window. With a couple years under my belt im finally gonna buy a grow tent and set up similar to this one: (just to give you an idea) http://www.htgsupply.com/Product-HTG-600w-Grow-Kit.asp#. I have a 5,000 btu a/c unit in the window. Will that air conditioner be enough to cool off the grow tent(600w light) and the spare room? Im gonna get an air cooled reflector and an extra fan for it. This part confuses me. Should I vent the exhaust from the light outside? Or should I vent the exhaust back into the spare room with the a/c.

vent the exhaust of the light out the window and have the ac as back up if it gets too hot......should be totally fine if you only have one light.

Better yet, pull air from outside into the hood and then exhaust the hood back outside. If you only have one window (and it is concealed from the public) then you can use a long vent pipe to make sure that the hot air exhausting wont go back into the intake.

How you want to set this up is going to depend on what your doing. What i mean is that if your going to do a CO2 setup you have no need to exchange the air in the tent and you can seal the room and the light and just run exhaust through the light and then outside. If your cooling the hood properly the AC should be enough i think. But if you are not going to setup a CO2 station that will generate everything your plants need i would suggest doing a simple setup with a carbon filter where you draw the the air from the room through carbon filter then through the light and exhaust it outside. In either case i would exhaust it outside. Why make your AC work harder than it has to? As for the CFM rating you need in either situation i don't know sadly. I tried to get some help on that front and it seems that most people will just say go overkill, you can always get a speed controller and turn it down. Also note that i have found several posts about those booster fans saying that although they are rated at 250cfm they will only generate that in a system where the air is already moving, in a system where they are the only extraction fan they are rated at 160cfm. not sure how true that is but i would look into it before purchasing and finding out the hard way.

rsharp said:

Hello everyone. I have a spare room that is approximately 6.5' x 6.5' x 7.5' with one window. With a couple years under my belt im finally gonna buy a grow tent and set up similar to this one: (just to give you an idea) http://www.htgsupply.com/Product-HTG-600w-Grow-Kit.asp#. I have a 5,000 btu a/c unit in the window. Will that air conditioner be enough to cool off the grow tent(600w light) and the spare room? Im gonna get an air cooled reflector and an extra fan for it. This part confuses me. Should I vent the exhaust from the light outside? Or should I vent the exhaust back into the spare room with the a/c.

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Here's what has worked for me in the past.



^6000 btu garage sale window a/c
6 inch centrifugal fan plugged into variac
2 1000 watt hps air cooled hoods
carbon filter with 6 inch centrifugal fan for scrubbing
65 pint dehumidifer
a bunch of digital timers
light controller

The intake and exhaust are on a closed loop from outside. No smell leaving the room that way.

I used a centrifugal fan sitting on a phresh filter sitting in the corner running 24/7. On top of the fan was a 90 degree duct bend to blow air over the plant canopy.

That setup was used in a crappy house bedroom. I used no fresh air intake quite successfully. I have a co2 monitor thinking that it might go down drastically with a ton of plants, however this was not the case. The whole you must recirculate the air in your room x times per x minute myth is bs.

Axial fans aka booster fans are crap for ducting or building pressure, their cfm ratings are not the same in ducting.

Exhaust fan turns on when lights are on, lights turn on during night.

Variac for exhaust fan for when the temps are very cold outside so condensation doesn't build up on the intake hose.