Need help with my room setup

Im trying to figure a few things out but having a hard time.
I did grew before, but my room setup was far from perfect.
I wanna start again..
This time with 5 or 6 600W HID with hood.
Its realy hot here in summer time. So i will have to use AC.

I want to use two fans to pull the air from the lamps, without sucking the air from the room. So it pulls air from outside, throgh the lamps and back outside.
In the hot days, that will be a problem since the air outside will also be hot.
So i could strecth the tube all across the room in the ceiling and back to the lamps.
So its actually use the same air, but because it take along time to get back to the lamps, its get a little cold thanks to the AC in the room.
And i should have another fan to pull air outside the grow room.
And another one that pull air to inside the grow room when the AC is not working.
Should i have both fans be at the same CFM speed?
Should the fan be at the same speed that the AC is? How should i know the speed in whoch the AC is putting air inside? Using CFM meter?
should i set the fan that pulls air inside to work only at night time?
If the AC take a break from inserting air because the temp is low, the fan will keep working and it will not have from where to pull.

I saw how to calculate the time needed to run a certain fan to pull the air from a given room size. But all those calculation are accurate to minutes. Should i use Cycle timer?
All the regular timers i could get my hands on in my country, are accurate to 15 minutes. So i could run for 15 minutes on and 15 minutes off, but that might be too long..
Or i could run them on all the time.
But then it will pull the cold air of the AC.
And if i will not run it, or not run it for a certain time.. The AC will put air in the room, and eventually it will find its way outside with the smell of my plants.

I know its a lot of questions but im confuse and dont wanna mess this up.

Ok I might not be able answer all those questions but I will try to point a couple of things out.
If you are pulling air from outside to cool your lights, it doesn't matter how hot the air is, the point of running air across lights is not to cool the light itself but to stop the heat from the lights heating up your grow room.
So run your two fans to your cooled hoods and straight back outside, don't add lots of ducts because it would take miles of ducting for the air to cool down and fans don't like lots of ducting.
Keep it simple, use the ac to cool the room, the ac manufacturer will tell you how much cooling it offers. You could run a sealed room and add co2 and use a big enough ac to do that. I'm not the right person to answer questions on what size would be right for the job.

When you calculate CFM needs for air exchange it gives cubic feet per minute, you can use google to convert that to meters cubed per hour. You don't run fans on minutes and off minutes, you run them 24hours a day unless your in a sealed room with co2, even then you want the fans that are connected to your cooled hoods on all the time your lights are on.
If you don't have a sealed room and use intake and outtake fans the intake should be less than the outtake, the carbon fiter reduces the flow on the outtake so you need to match that reduced speed so that you maintain a negative pressure.

I know you had many more questions but you would be better off asking a couple at a time in a new thread to stand a better chance of getting answers.
Try rephrasing it by saying I want to run X amount of lights in X amount of space. What fans do I need and how big does my AC need to be.. I would guess a sealed system with co2 and good AC would be the best way forward

Thank you.. I think you cover all my ques..
I did some more reading after i posted my ques so got some answers.
All those calculation of how much AC BTU and CFM i will do myself when i know the exact space.
And if need to will tweak the room t'ill it almost perfect.

coreywebster said:

Ok I might not be able answer all those questions but I will try to point a couple of things out.
If you are pulling air from outside to cool your lights, it doesn't matter how hot the air is, the point of running air across lights is not to cool the light itself but to stop the heat from the lights heating up your grow room.
So run your two fans to your cooled hoods and straight back outside, don't add lots of ducts because it would take miles of ducting for the air to cool down and fans don't like lots of ducting.
Keep it simple, use the ac to cool the room, the ac manufacturer will tell you how much cooling it offers. You could run a sealed room and add co2 and use a big enough ac to do that. I'm not the right person to answer questions on what size would be right for the job.

When you calculate CFM needs for air exchange it gives cubic feet per minute, you can use google to convert that to meters cubed per hour. You don't run fans on minutes and off minutes, you run them 24hours a day unless your in a sealed room with co2, even then you want the fans that are connected to your cooled hoods on all the time your lights are on.
If you don't have a sealed room and use intake and outtake fans the intake should be less than the outtake, the carbon fiter reduces the flow on the outtake so you need to match that reduced speed so that you maintain a negative pressure.

I know you had many more questions but you would be better off asking a couple at a time in a new thread to stand a better chance of getting answers.
Try rephrasing it by saying I want to run X amount of lights in X amount of space. What fans do I need and how big does my AC need to be.. I would guess a sealed system with co2 and good AC would be the best way forward

Click to expand...

It really matters how the air temp outside the growroom is that is being used to pass through air cooled hoods in a closed loop system. Big time. In the winter here in Michigan....its too cold passing over the hoods and bulbs and summer months....too warm. First off...the op is on the right track with air cooled hoods being on its own closed loop ducting and fans. Lamp timer turning on the blowers SUCKING OUT (very important- no matter what you hear or read....sucking out with the blowers close to the exit hole is best pwriod). What you want largely depends on where your setup is on the planet...climate wise year round. Its the reason you get so many varying answers on the forums. At any rate....the best answer i can give is to pull air from the general area the growroom itself is in...with option holes and flanges for true outside air to be sucked through the hoods depending on conditions and seasons. And the exit where the blowers are doing the sucking definitely to the outside...and preferably the blowers are outside the growroom. Because they radiate all the warm air. If ya cant do this then insulate the blowers best you can. They actually make insulating covers on some blower brands. Speaking of which...a very underrated item for air cooled hoods is the insulating covers for the hoods themselves. Some hoof brands have these as an option ot you can make your own out of insulation blankets or moving blankets. Also...for the most efficient setup...definitely use insulated duct work. 6 or 8 inch. And if you dont want dirty dirty hood glass mid crop...reducing plant light...use some kind of filter on the intake. Pantyhose or pieces of furnace filter stapled real good around the intake hole works great but you gotta change it every crop or two. Filters made by Dust Shroom are really nice but pricey. If you live in most climates in America where summers can get roasting...and with multiple air cooled hoods....your still gonna need room air conditioning more than likely but just not as much. Try and keep your air cooled duct bends to a minimum too. Use a 460 cfm (common) six inch blower minimum for every couple thousand watts. And again...use the blower sucking out..after all the hoods...plugged to a hole and flange outside the growroom. Insulate the blower...ducting and hoods themselves with blanket covers for maximum efficiency.