# Air cooled hoods



## grodude (Jun 14, 2015)

I'm going to use air cooled lights on my next grow and I'd like to know any important info about them from those more experienced. I heard not to have more than 2 connected, is this true? How many cfm do I need for each 600w or 1000w light (depending if I use 2 or 3 lights)? Do I blow the air or pull? 

3-site RDWC setup in an 8x4x7 foot tent. I will be using a 740 CFM fan for the room separately. I would prefer 3 600w lights, but heard I should only connect 2, so if that's the case I would use 2 1000 watters

Are these tips accurate?

http://www.just4growers.com/blog/10-tips-for-setting-up-air-cooled-grow-lights.aspx


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## budz4me (Jun 14, 2015)

I run a 400W and a 1000W off of one 6" 700CFM fan. I use a "y" fitting on the intake, and run one duct to each cool-tube. I dont think you would want to run the cool-tubes in series with one another...the heat from the first light will be pulled over the next light, etc...which may lead to issues.

the CFM requirement is more dependent on your cubic feet.  Your tent is 224 cubic feet.  That means the air in your tent will be changed every 20 seconds. That is a ton!

Cooling of the lights does not require a whole lot of air. I would run a "y" fitting  and off that "y" run 2 seperate ducts for each cool-tube, then get a fan speed controller to slow the motor down to the point where the bulbs are cool, but yet you are not sucking the side of the tent in, then the passive intakes will draw enough fresh air in to keep the tent full of fresh air.

Always pull the air (fan outside tent, sucking in air from the tent.)


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## grodude (Jun 14, 2015)

I am also considering 4 400 watters, but if I did that I would not have an open duct for a separate inline fan for the room. Is that a possibility?

I would be worried about the light distribution if I used different wattage bulbs


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## gottaloveplasma (Jun 15, 2015)

Ceiling port?


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## umbra (Jun 15, 2015)

grodude said:


> I'm going to use air cooled lights on my next grow and I'd like to know any important info about them from those more experienced. I heard not to have more than 2 connected, is this true? How many cfm do I need for each 600w or 1000w light (depending if I use 2 or 3 lights)? Do I blow the air or pull?
> 
> 3-site RDWC setup in an 8x4x7 foot tent. I will be using a 740 CFM fan for the room separately. I would prefer 3 600w lights, but heard I should only connect 2, so if that's the case I would use 2 1000 watters
> 
> ...


 No those tips are not accurate at all. You can connect the 3 lights together and you want to pull the air thru them. The 740 cfm should be enough. You want to run the duct from outside the tent to the first light, to the 2nd, then to the 3rd. Connect the fan just before the out port of the tent, or just outside the tent and vent it into another space. Otherwise you will be taking hot exhaust and bringing it back into the lights. This will not help much. The best way to keep the tent cool is by removing the heat.


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## gottaloveplasma (Jun 15, 2015)

I thought you should push air through them to not get fan hot or suck stinky air into the exhaust.


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## grodude (Jun 15, 2015)

umbra said:


> No those tips are not accurate at all. You can connect the 3 lights together and you want to pull the air thru them. The 740 cfm should be enough. You want to run the duct from outside the tent to the first light, to the 2nd, then to the 3rd. Connect the fan just before the out port of the tent, or just outside the tent and vent it into another space. Otherwise you will be taking hot exhaust and bringing it back into the lights. This will not help much. The best way to keep the tent cool is by removing the heat.



The link I sent said you could connect 3 together, but it had to be 8" ducts instead of 6". I wasn't sure of that was accurate. If I do 2 1000 watters with that height would the tops get too hot and burn? What's the closest I could get them to 400w, 600w, and 1000w when they are air cooled?


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## umbra (Jun 15, 2015)

I run 2 1k in a 4x8 tent. I am in Cali and temps are hot to begin with. I keep the lights about 18" from tops of the plants. I run a 2nd fan connected to a carbon filter inside the tent and an oscillating fan inside the tent. My temps never get much above 80* F. I have a temp and humidity gauge inside the tent hanging down from the lights just above the canopy. With 3 600W, the 6" duct may require more than 740 cfm. Sometimes you need to play with things to get them dialed in.


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## pcduck (Jun 16, 2015)

gottaloveplasma said:


> I thought you should push air through them to not get fan hot or suck stinky air into the exhaust.



I pull my air through 2 600 watters with the cf outside the tent. Works for me.


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