Hi again I have 6 of these in the 6mx 6mx 7ft space the room is not airtight it does have little air leaks . I am planing on a big intake and a big outtake but I need to know roughly how big? Or will I need multiple intake and outakes. If I move the hot air quickly enough out will it keep the room at optimised temps
Those tents usually have 8 inch ducting vents, for 6 600 watt lights you're going to need at least 2 8 inch inline fans just to remove the heat. If you're growing anywhere where it's over 80 degrees outside, the inline fans are only going to be able to bring your grow down to the ambient temps at best.
I'm running 4 of those same lights, with 2 hooded 1000 watt bulbs. I have 2 15k BTU window air conditioners running just to keep the room at 80-82.
With 3600 watts in open hoods, you're going to be generating 12,600 BTU of heat every hour. This doesn't account for the heat that the rest of your equipment is generating, nor does it account for the room itself, that figure is just for your lights. A quick google search showed that with a 6mx6m room (1m=3ft I believe?) you're at 324sqft which requires a 9k BTU unit alone, again this doesn't include your lights and equipment. A 15k BTU window unit would
barely be able to keep up with your tent, seeing as the tent you have isn't perfectly sealed that's going to be another issue.
So, since you'll be needing a 9k unit just for the room alone and your room generates 12,600 in heat from the lights, you'll be needing 22k BTUs of cooling power at a bare minimum.
So we've determined you're going to need around 24k BTUs of cooling power and you have a handful of options as to how to go about this. You can either go with 2 12k units, one on the left and right hand sides of your tent. Or, you can go with 3 9k units strategically placed around the tent to provide even cooling throughout the room. With air conditioning, it's better to have too many than too little. If you have too many you can simply shut one off so things run more efficiently. If you have too little, you're SOL and your yields will suffer greatly.
I made the same mistake with my first indoor grow, barely pulled 2lbs from 2000 watts which is pathetic. I had a single 12k unit at the time and it couldn't ever keep up, and this was before dimmable ballasts so I was fucked.
Not trying to be an ass, but unless you can spring for the air conditioning you may as well shut things down or at the very least shut down half of your lights. Your quality and yields will suffer immensely if you don't get the temps figured out. Don't be like me and lose money because you don't want to spend the money on cooling, I still regret that indoor grow to this day and would hate to see anyone else in the position I was in because of it.
