Need help with a venting issue.

So I have a two room setup basically a 5'x12' rectangle split in half and done up as two rooms. I have a 400 cfm exausht fan pulling on the far right of one room with a light proof vent on the wall separating the two. On the far left wall of the other room I have a 2'x2' passive intake. Well heat was becoming an issue so I added on a 3.5' x 11' sealed foam board room with a 12k btu portable ac/ dehumidifier. ( this room connects to the other room by the existing passive intake) My thinking was that there would be enough suction to pull cold air Thru and cool a few degrees at least. Well the cold air isn't coming thru and I can feel it in the bottom of the vent swirling around. Any and all info welcome. Thanks. Very crude drawing but hope it helps

If I were you and if you can cut holes in the walls of your 5x12’s the. I’d put two of the smallest window AC units that you can find in each of those rooms so that they’re controlled independently. Going this route would also allow you to supplement co2 more efficiently because those window AC units don’t exhaust air outside or intake it from outside like your portable unit does (lots of dual hose designs still do this (Re: Whynter)).

MFL said:

If I were you and if you can cut holes in the walls of your 5x12’s the. I’d put two of the smallest window AC units that you can find in each of those rooms so that they’re controlled independently. Going this route would also allow you to supplement co2 more efficiently because those window AC units don’t exhaust air outside or intake it from outside like your portable unit does (lots of dual hose designs still do this (Re: Whynter)).

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I dont think window units are doable in my situation. I got it working somewhat but I'm sure there is a right way to do it. I just know nothing about air movement and positive/ negative air pressure. I am thinking if I keep positive air in the lung room and negative in the grow rooms the cold air should be pushed/ pulled thru. But like I said I know a lot of nothing and know even less about aerodynamics.

Bucsfan80 said:

I dont think window units are doable in my situation. I got it working somewhat but I'm sure there is a right way to do it. I just know nothing about air movement and positive/ negative air pressure. I am thinking if I keep positive air in the lung room and negative in the grow rooms the cold air should be pushed/ pulled thru. But like I said I know a lot of nothing and know even less about aerodynamics.

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What kind of intake do you have on the lung room? Is it connected directly to the A/C unit with ducting?


Edit: From what I can see the AC is cooling the lung room but if you want that air to circulate through the other two rooms you need a passive intake on the lung room, or you can plumb your exhaust fan back to the lung room and have a closed system.

B|uDreamer said:

What kind of intake do you have on the lung room? Is it connected directly to the A/C unit with ducting?


Edit: From what I can see the AC is cooling the lung room but if you want that air to circulate through the other two rooms you need a passive intake on the lung room, or you can plumb your exhaust fan back to the lung room and have a closed system.

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Maybe a few more passive vents in between the two rooms as well.

B|uDreamer said:

What kind of intake do you have on the lung room? Is it connected directly to the A/C unit with ducting?


Edit: From what I can see the AC is cooling the lung room but if you want that air to circulate through the other two rooms you need a passive intake on the lung room, or you can plumb your exhaust fan back to the lung room and have a closed system.

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The lung room is connected to the other rooms via the passive intake. That's why I built the lung room where I did cause that's where the intake is. I guess I'm just stupid and thought I could use that ac to cool idk now im like if I go sealed then it's more$ for co2 im kinda lost

You just need some sort of intake from the lung room to the outside space and it should pull the cooled air through both rooms. Your fan is creating negative pressure in all 3 rooms but there is nowhere for fresh air to enter because you created a sealed lung room over your old intake.

B|uDreamer said:

You just need some sort of intake from the lung room to the outside space and it should pull the cooled air through both rooms. Your fan is creating negative pressure in all 3 rooms but there is nowhere for fresh air to enter because you created a sealed lung room over your old intake.

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Shit I didn't mention I have a 2x2 opening on far left bottom of lung room. Maybe I'm not giving enough time to cool. I'm not very patient I guess. Just seems like the exhaust will just pull cold air out without cooling

Where is the ac venting the hot air too? I was venting to a lung room but because of the hear being vented to the to that I was also taking fresh air in made it impossible to bring temps down enough. I had to vent the hot air outside and then bring lower temp into the ac controlled to for better results. Good luck

HighlyMedic@ted said:

Where is the ac venting the hot air too? I was venting to a lung room but because of the hear being vented to the to that I was also taking fresh air in made it impossible to bring temps down enough. I had to vent the hot air outside and then bring lower temp into the ac controlled to for better results. Good luck

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It was venting into the basement only because I had no other option. I actually stopped using the lung room for now because of that. I figured out I can vent into chimney only problem is it's on the opposite side of the basementNas the lung room. Right now I have my 400 cfm acting as an intake sucking cold air from upstairs into one grow room and my 8" ac infinity as an exhaust dumping into the chimney. It's working well so far can drop the temp quick if it gets to hot

I guess my next project is to seal the rooms all up and run c02 but that's gonna be a long project

Bucsfan80 said:

I guess my next project is to seal the rooms all up and run c02 but that's gonna be a long project

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Reach out if you need help, here's my setup: