6k room cooling question

hey guys. this is my first post on RIU but i've been lurking for months. i'm in the process of designing my first grow room. i've found tons of info but only a few things are missing from my set up.

i want to run 6 1000W HID lights. room is about 8'x12'. i plan on using cooling hoods. i want to run 2 lines of 3 lights, with an exhaust fan on each line. sucking air in from the attic and exhausting outside. my main question is how often and how long do i need to run the fans to maintain optimal temps? and what CFM would do this best? do i need to run them the whole time the lights are on? or just when temps get high?

and since i will be cooling the lights independently could a window unit cool/heat the room sufficiently? i read that with cooling hoods it cuts cooling needs in half. so 3000w x 3000 = 9000BTU .. is this correct? i will be growing in Massachusetts, with cold winters and 80-90 degree summers.

Either wire a reverse thermostat,or buy one ready to go.
set it to 77-80 every time it its that tem the fans go on

your inline fans that are cooling your hoods must run the whole time the lights are on. or it will get hot as fuck and a bulb with shatter. IMO no way is 9k btus worth of ac going to cool a 6 lighter. get a 2 ton unit and youll be good to go. sounds like you got your heart set already but i wouldnt put 6k watts in an 8x12

patrickkawi37 said:

IMO no way is 9k btus worth of ac going to cool a 6 lighter. get a 2 ton unit and youll be good to go. sounds like you got your heart set already but i wouldnt put 6k watts in an 8x12

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the reason for 6 lights was because of the room size.. didn't want to waste space.
u think 4k would be better?
i was thinking window unit because they r cheap.. a 2T is a little pricey for my budget. and from all the videos i've watched i've seen window units and portables.. but never a 2T... any suggestions? nothing is final yet

my room is 12x14 and i still feel like i need more space and im rocking 4600 watts. 5 lights. your probably going to need a dehumidifier, a bucket of some sort, maybe a res, at least some space to use as a center when your moving plants around.. a 4x4 canopy is a little small IMO for a thousand watt bulb.if you know your going to kill it then sure why not. but if you do a 5x5 pattern or 4x5 its just extra weight. ive even done a 5x6 pattern with 4k watts and didnt have a fluff problem. but with a 4x4 you for sure need to fill the entire canopy if you want to do worth a damn, you wont be able to walk around at all in there if you did 6.
i had a 12k wall unit, it was barely able to handle my 4 lights when i was air cooling my hoods. and i live in the mountains and run at night. summer was kind of a bitch. i know you said your on a budget, but its better to have too much than not enough. if your going to buy one of the ghetto wall units you can probably find a 2 ton on craigslist for under 200 bucks.

are you going to be bringing in fresh air? or Co2?

go ahead and invest in a GOOD AC, your going to need it in the summer, 6inch or 8inch CFM fan and keep the fans running as long as the lights are on. Go ahead and add a co2 generator and monitor as well.

Also since i am a nice guy I will give you a little tip, i have grown with cooler temps as well and When you air cool your lights you will have cold air meeting hot bulbs incased a reflector with temper glass, if the humidity is high in your room it will cause condensation on the temper glass of your reflector. Make sure you get a good dehumidifier to keep humidity under 55% or else your first light on each string will have condensation all over and it will hurt your yields. your welcome in advance.

thanks for the insight. i completely spaced on room to walk and for my res and stuff.. 4x4 per light is what i was thinking. so 4 lights sounds a lot more logical now. money isn't tight but i didn't want to waste $1000 if i didn't need to.
the plan is to run a few cycles with a negative pressure room, then when i'm all dialed in maybe upgrade to co2, and seal it off.

jpill said:

Also since i am a nice guy I will give you a little tip, i have grown with cooler temps as well and When you air cool your lights you will have cold air meeting hot bulbs incased a reflector with temper glass, if the humidity is high in your room it will cause condensation on the temper glass of your reflector. Make sure you get a good dehumidifier to keep humidity under 55% or else your first light on each string will have condensation all over and it will hurt your yields. your welcome in advance.

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hahah thanks a lot.. thats why i'm here, great advice!

what about window unit/portable AC letting out smell?any way to avoid this??
2ton or mini split is not an option because i have nowhere to put the outside unit.

the portable AC will def. let smell out. You can get a portable AC unit that go's in the room. You just have to vent the hot air that is produced.. I would strongly advise you get a co2 generator and monitor even on your first run. It can increase yields up to 25%

fuck my bad. ya where i live its cold and the condensation was dripping on my plants cause the cold air from outside mixed with the hot ass bulb= a leaky fucking mess. so during the winter i stay completely sealed and use the adjusta wings ( non air cooled hoods). they are hard to cool and you got to trust your ac with your life cause if it shits out your toast.

when your saying your going to do negative pressure what does that mean? what are you going to be pulling fresh air in with? and how are you going to warm that air up? i wouldnt be bringing in fresh air if its winter cold out. you should just seal up and do co2 from the get go. save yourself the headach. if your going to get a generator just know that will add about 7 degrees to a room that size keep that in mind with the ac. also the window acs arent sealed and smell and air creeps out wasting co2 and fluctuating your ppms. seal that bitch as tight as you can get it. figure out a way to use a mini split.. i keep the outside unit sitting outside my box but still inside the garage. it doesnt work as efficient in the summer but she still gets the job done. i wouldnt cheap out on a good AC its a really important tool with indoor growing. a good 2 ton is about 1500 bucks but you will be able to sleep at night knowing your rooms in good hands.

I have a 12 wide by 19 long room with 6k watts... 5x13 has 3k over it and oposite side of room 5x13 had 3k over it. Have extra space in middle of room to walk and few feet on each end of room for the 2 portable 12k btu ac.

My temps with door shut with adjust a wings stays at 83* which is awesome considering my ac isnt plugged in yet! Did awesome job on sealing my room though so humidity went to 73% fast... i opened door and humidity went down to 60% in 15minutes and temps went to 77*. Monday im hooking up my co2 generator to gas line and turning 2 ac on which both act as dehumidifiers also.

so let me get this straight, you have 6 1k lights non air cooled in a sealed room with no AC running and your temps are at 83* .. Thats bullshit.. If your in a sealed room with no AC and 6 1k adjust a wings your temps would be well over 100*F .

Just ran the room today for first time with 12 plants in it. I have a thermometer under each set of 3 lights (2 total). Each one shows humidity. And temperature. With high and low setting. While i was there working on other stuff i looked inside and checked the high and it was 83*. Not too hard to explain. There is a ton of room in there and fans blowing. Its not compact at all so it would take time for heat to add up everywhere and when the surrounding space outside the room is 40* it helps also. I was there with room for 5hrs today an that was the high. When i left i left the door to room open cause temps were in 70s that way cause no ac until tmr.

Not in any way saying it will stay that way but thanks to cold weather and running my lights late when its coldest it takes less electric to run room. Trust me if i knew i could get away with just one ac for this harvest i would not have spent 1100 on 2 of them to just sit there. The room WILL need ac but for right now i guess it is working fine without. If my temps are low 80s for the co2 then im happy. Im expecting to need the acs for that temp at some point... i posted to pretty much show him i had similar setup and if he made his room alittle bigger AND air cooled he would be in better place.

all this info is helping me guy. thanks.
i found some $600 mini splits. i might give that a go. and like patrick said just leave the outdoor part out of the room.
i wanted to run co2 originally but i thought save the money for when im better at growing, because this will be my first real grow. i did a bag seed outdoor grow but that was just goofing around.
so this is my proposed set up now:
4 1000w air cooled HIDs
2 fans, 8" for lights, 6" for scrubber
6" carbon filter
4 oscillating fans
split mini with A/C, heat, dehumid
and light controller, timers, and fan speed controllers
MAYBE CO2 if there is still money

anything im missing??

You will need at least 5000btu of cooling per 1000 watter.

if your counting on your AC to act as your dehumidifier it wont work out as planned. Granted an AC unit is technically "somewhat" a dehumidifier, it wont handle the amount of moisture that is going to be in your room, at least not in my room anyway which is 400 sq ft.!! I have a 4 ton Central AC and needed two separate dehumidifiers for my room. With the central AC and two dehumidifiers the humidity is still at 50% ! Its fucking terrible ! I decided that I have no choice but to go and buy an "air sponge" from Home depot, its a commercial dehumidifier that eliminates 130 pints a day. I have no choice, the standard 50-70 pint dehumidifiers break within 1 year and they cost anywhere from 200-300. I know this from experience, you have to run the dehumidifier non stop so it breaks within a year / year n a half.

jpill said:

the portable AC will def. let smell out. You can get a portable AC unit that go's in the room. You just have to vent the hot air that is produced.. I would strongly advise you get a co2 generator and monitor even on your first run. It can increase yields up to 25%

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with a room that small and that many lights.. in order to run co2 with correct temps and proper air flow would probably require a 1000 plus dollar environmental controller. not to mention the generators aren't cheap either.. Your getting into some bucks...

That many lights in such a small area is just complete over kill imo... keep it simple until you get a couple runs in.. then modify. it'll save a lot of headaches

so true i would skimp on wattage so that the room could be perfect enviromentally for a efficient use of the light which is expensive to run rather than have too much light and plants that you cant deal with it grow wise end up missing things, no due diligence .. all the while paying the electric bill.....

well, he said money isn't an issue. Why not just go hard from the beginning.