Nubie Air Balance Problems

So a little frustrated here. Trying to take a smoke a bowl and chill until the solution presents it self, but thought I’d ask the experts as a back up plan.

Brand new set up in a finished attic space. The attic has a vent open to outside where I run my exhaust duct and also a small window. I was worried it would be too cold so I insulated the vent and windows, but once I hooked up the lights I had a heat problem…up in the 80’s. So I took the insulation off and I bought a portable AC unit. 8000 BTUs. Good for 10x10 space. And still can’t get below 75F with all 3 lights on. I have the AC unit exhaust venting outside the tent into the attic space so I know I should duct to outside and will.

But running AC and everything… the tent is under negative pressure and won’t get into the 60’s.

Any help would be appreciated.

  • 5x5x5 tent
  • 6 inch exhaust fan in canopy
  • 3 x 260 xl HLG lights
  • AC 8000 BTUs
  • 2 small oscillating fans at 2.5ft height
  • small humidifier on the floor
  • Small heater outside the tent no using.
  • one tent vent. Other one closed

Outside temp gets in low 50’s in San Diego
Attic temp 60-72F
Tent temp with everything running I can t get lower than 75F
Tent humidity is 40 tops

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I don’t have any worries until I hit 85F. I run mine at 82 and would have it at that at night too if I could do it without heating the space. Better hope you are done with your grow before things warm up…

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Maybe try moving the exhaust fan to the top of your tent that’s where your warmest air is going to hang out :v:

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Yes 75 is perfect! Remember that AC units remove heat and need to expell it. If you dont expell it outside or into your house it will ultimately do nothing because the coldnit creates will be offset by the heat it ejects. If the rooms ambient temp is 75, the tent cannot get below that and in fact will be warmer because the lights will radiate in there. Therefore, if your room ambient temp is mid 70s simply ventilate the tent outdoors more agressively to evacuate the light temp. If you have a fan controller set it to vent at 76f and it will remove air, which is important too!

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My plants really explode with growth in the 80s seems like 83 to 88 degrees they just pack it on
If you can measure your space LXHXW= cfm and then go 20% over that number and match it to your exhaust fan cfm i don’t know everything but this has worked great for me when doing new grow setups hopefully this helps


Thank you everyone for your help. Well I guess 75-80F ain’t that bad after all. I was shooting for 70-72F because that’s what Ive been reading as ideal. But it sounds like my fear of burning plants might be getting the best of me. By the way I’m not even germinating for a month cause I just want to dial it in as much in as possible.

So my exhaust is sucking 402 cfm. When I do the calculation 5x5x5=125 + 20% = 150 cfm. Seems like maybe I have too much suction? Maybe just keep it on low or like ThcinKC says set to auto at 76F. I will do that. My filter is already at the top so I’m good there.

So another question. The AC unit is pulling air into the tent as well right? Through the intake right. So that’s even more suction! Should I run my AC outside my tent and duct it into my tent?

I guess I could also run just to of my lights to reduce heat, but would rather not.

Thanks for all your responses! You guys are awesome!