What size to air cool lights

Obviously the bigger the better but for cooling 2 600w hooded lights whats the best way 2 small fans, 1 big fan ? one fan blowing and one pulling through both hoods,

The combinations seem endless what works for you?

my lights are positioned so it would have to be a Horseshoe type of setup if i was to connect them both.

swordfish984 said:

Obviously the bigger the better but for cooling 2 600w hooded lights whats the best way 2 small fans, 1 big fan ? one fan blowing and one pulling through both hoods,

The combinations seem endless what works for you?

my lights are positioned so it would have to be a Horseshoe type of setup if i was to connect them both.

Click to expand...

Depends on the room. But I'd suck through one and push through the other.
aka: fan between the lights.

But try it and see. Make it so you can easily change the config. Run it for a few hours, check glass temps, switch around and re-test.

Different fans can/will produce different results.

(Ran a S&P TD150 on slow speed just for a 400W and could keep my hand on the glass and a cold beer on top of the hood)

It depends how cool you need them to be.
I'd say around 300cfm for both is series would cool them nicely.
I use a 300cfm vent on 1x400W and its about 4°C hotter than ambient over the cooltube (touching it) when the inner reflector is on. (so no radiant heat which air cooling doesn't help with)
I guess I would be safe with my 75cfm vent using it and get a few more °C but really nothing major.


However, the most effective way is air from the outside with a passive intake and one big vent sucking out. You could either put them in series and use 1 vent, or vent them with a vent for each.
Venting both together would requier only 1 vent that should be much cheaper than a vent for each. However, the heat from the first light will travel to the next one creating temp. difference so if you do it this way put the second light in the cooler part of the room.

I have a 4x8 tent. I am running 2x 600 watt hps. I run a 6 inch s@p td-150 pulling air straight through the tent and both cool tubes and out of the room the tent is in. i also have a vortex 6 inch exhausting the tent out of the room the tent is in. this keeps my temps around 7 degrees higher then ambient temps right under my cool tubes(77-79 degrees)

smokintreez said:

I have a 4x8 tent. I am running 2x 600 watt hps. I run a 6 inch s@p td-150 pulling air straight through the tent and both cool tubes and out of the room the tent is in. i also have a vortex 6 inch exhausting the tent out of the room the tent is in. this keeps my temps around 7 degrees higher then ambient temps right under my cool tubes(77-79 degrees)

Click to expand...

i got a 4x8 room with 2 600s the hoods im looking at are only 5 inch outlets though did you have to use a reducer?

swordfish984 said:

i got a 4x8 room with 2 600s the hoods im looking at are only 5 inch outlets though did you have to use a reducer?

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5 inch? Odd. 4 & 6 are typical. I suggest getting biggest hood outlets. Its cheaper to change the duct/fan then a new hood. Plus if you get a smaller outlet on the hood and need more, the smaller becomes restrictive.

id say go with 300cfm exhausting the tube and 75cfm for the cab itself plus a small oscillating fan and you will be lookin at 70-80F and some very tasty bud

But at the same time, i dunno if 150cfm would even be enough to cool a single 400w, opinions?

hi guys just thought id pop me 2 pennies worth in,
this is what i would do ( have done in the past )
scrog setup
3ft depth, 4and a half ft wide, 4ft hight ,
so as you can see quite a small space a totally stealth

2 x 400w hps
2 x cool tubes
450 cfm super silent rvk exhaust fan
climate controll box
3 x 5" computer fans
2 x 6" oscilating fans
purchesd a fogger due to humidity probs and worked fantastic

ok so this is what i did , cooltubes set parralel to each other at even intervals
intake hose direct form north facing wall into box through cool tubes ( horse shoe shape ) vented back out into room ( saved a fortune on heating bills )
oscilating fans on permanant, one above screen and one below
home made filter and 3 computer fan setup which also vents back into room
all fans except oscilating fans controled by climate controll fogger also controled by climate control.
grew 8 plants in that setup had a record finish of 60 days for an average of 120g per plant
so basically what im saying is buy a decent fan bigger than what you need cool your lights inline, if you can take cold air from outside and vent through your lights and then vent your grow space independantly but you dont need huge expensive fans.

with this setup i can set the temp i want night and day and the humidity feeding is on a timer set hydro system so i can go away and forget about it