super noob here. second year of growing, sort of. just a 2'x4'x5" tent. I have a 6" exhaust fan I never used (Ipower big round and loud), vents up into the attic of my home. never seemed to need it? if their was an odor I didn't notice nor did I care. I've only been trying to grow autos, trying to diminish the hurting on my wallet going to dope dens for my medicine, plus I don't think it's all that good any ole way. I'm 65 years old and on a fixed income. So anyway I've been doing some reading, says I should use the exhaust fan to bring in fresh air for the plants to breathe and get oxygen. Okay, I don't get the best production, nothing like I see in the pics on the internet and you tube. But I'm not greedy either. So I thought I'd give it a whirl. Zipped up the tent, turned on the fan, I have it on a controller, sped it up till a tissue would stick to the carbon filter (has cover thingie over the filter) a couple minutes later my RH is down from 52 to 40% and the temps go up 2-3 degrees. I should add that I have a 6" inline fan at the bottom of my tent pulling in air. so I have to turn on the A/C, (window unit 5,000 btu) to draw down the temps., but that does nothing for the RH, plus I'm now using more electricity. I get the thing about recirculating or replacing the air in the tent. But how is the fan any better than what I was doing before. I live alone out in the country, no friends to come by so I just leave the tent flap/door open bout a third of the way, regulate temps by the a/c or closing the bedroom door or just cracking it open a bit. with the inline fan pulling in outside air, the flap being open, I have a tower fan in the tent (oscillating). Both fans run 24/7. It's getting cooler where I'm at now and would like to remove the window a/c unit and pull the cool air from outside, possibly with another 6" inline fan on the other end of the tent. Or just pull in cool outside air with one of those window fans I have with 2 fans that are reversible into the bedroom and again control temps with the door inside the bedroom with the door? It just seems like a huge waste to be pulling the RH out and away from the plants when apparently it is needed also? right now I"m not running the a/c. It's 72 degrees outside. 71 degrees in my house, bedroom door open so I'm pulling in air from the whole house? the tent flap is open bout 1/4 of the way, exhaust fan running, inside tent fans running, and humidifier chugging along inside the tent. it's 80 degrees with 39% RH inside the tent. I can turn off the fan and it's like 78 degrees and 48% RH. What am I missing here? I'm so sorry for the rambling on, I've done searches, watched you tube vids and everyone says you HAVE to run an exhaust fan. I'm really confused, seems easier and cheaper my way w/o the dang exhaust fan. I have a Viparsrectra VP2000 and two mars hydro 600 led lights in the tent. I keep my tent clean too. Again so sorry for length, trying to give all pertinent info and such. I really enjoy the emails I get from Nebula, very informative.