I’m testing my 4’x3’x60" tent inside an outdoor building. I’m using a 4" fan, carbon filter inlet and outlet, led light. Not wanting to kill plants, so I’m test my environmental control ahead of time. Here is my situation. I live in the deep south of the USA. Current temperature out side is 75 f with 70% rh at night 90 f during the day with 95% rh and its barely starting to get summer.if I turn on my fan the temperature of the tent rises close to the outside temperature. So I have a few questions. If I air condition this building and move my inlet inside instead of outside will I still be getting the proper fresh air needed for the plants. Open for any suggestions.
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You are going to have issues when you go to flower. Bud rot and mold with the rh that high.
I have my inlet with my carbon filter in side my tent. Vented air goes outside you will probably need a dehumidifier to for the high rh. Here is a pic of my setup
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Thanks ThcinKC
If your inlet is inside the tent where do you draw fresh air from? Like I said before this is my first indoor setup.
The bottom side of my tent has a flap that opens and air comes in through there
The inlet will make the room the same temp as the air being sucked in to room
Add an exhaust fan
Welcome to forum. You definitely need an ac in there & that will help with temp & humidity. You will need sm fans inside tent to move air around. Im in south & a dehumidifier is needed. Your humidity & temp are too high & unfortunately a dehumidifier throws a lot of heat.
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Thanks Laurap
Like I said before I don’t have plants in this danger. I’m getting my temp and RH under control in advance. I’m adding a/c to this building and a dehumidifier. My biggest question was, is it ok to use room fresh air from an a/c room and not fresh outside air. From what I’m seeing in replies I guess so.
Maybe I was thinking too technical.
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You definately need to get the RH down to acceptable levels , preferably somewhere around 60% for veg and 40 to 50% for flowering. I think the only way forward for you is a dehumidifyer as has been mentioned above combined with some AC. Your carbon filter will not function efficiently abovee 70% relative humidity, the moisture in the air simply blocks the pores of the filter, this in turn reduces the efficiency of the exhaust fan and further compounds the issue.
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Normal A/C units already act as a dehumidifier. (I’m not saying you want also need a dehumidifier) Cool air from the rest of your home likely has a much lower humidity than in your grow room. My grow room has portable ac unit, but I also have a box fan in the door way blowing cool (low humidity air) from the rest of the house.
I’m currently building a 12x15 grow room. I’m going to install a small air conditioning unit in it! Will I need a dehumidifier? And for the winter I was going to install a small propane heater ! Do you see any problems that I might run into? Thank you!
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Idk about the heater but I have a room inside a room and the bigger is about that size with a window unit runnin 24/7 set at 68 degrees. Given its hot and humid where I live the inside of the room with lights on is 46 Rh and 75 degrees F. Lights out Rh jumps to 78 and temp is 68 F so I’m going to need a dehumidifier for flower. Hope this helps 
Yeah that helps! Thanks!
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I forgot to mention my light is an led so Temps may be different if your using hsp/mh. 
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Propan eats oxygen so if that’s in the room it will change oxygen lvls for the ladies
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Thanks mountainman1 I did add a/c and a dehumidifier to the setup. With out side temps in the high 90’s and RH in the 90’s I’ve managed to keep the tent at 75 degrees F and Rh down as low as 45%. With the led lights on .Looks like fighting the elements is working.
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