I’m using an AC Infinity 6" exhaust fan in a 3x3x6 tent with three large plants. The humidity in the lung room, where I have a dehumidifier running, is 43-45%, but in the tent it is over 60%, even with the exhaust fan running at full speed (setting 10). I have two large vents open at the bottom of the tent, and the fan is at the top, pulling air through a charcoal filter and out the top port. I feel very strong airflow out of the exhaust port.
Why is the humidity in the tent so much higher than in the lung room? I am in flowering and would like to get the humidity as low as possible, at most 55%, preferably even lower. How could I change the setup to help with this? There is not enough room to put the dehumidifier in the tent.
Plants also respire moisture. Try also pushing air into the bottom of the tent. I push air into my tents with fans at the bottom of the tent rather than have passive intake there.,
I also use a dehumidifier in my lung room. I also open those two velcro covered vents however I put a small box fan in front of each vent outside the tent blowing the long air into the tent allowing my dehumidifier to work perfectly.
It also is a excellent source of fresh air blowing into the tent.
Im in the same boat!!! Im in New England! Humidity in my area right not is in the 40’s. Lung room in low 50’s? In my tent is pushing 80’s??? Temp is low 60 degrees. How is that even possible. My babies are sleeping right now. 6in fan in a 3x2 set at 9! All AC infinity equipment. Have ac and dehumidifier on and haven’t watered since Wednesday night.
I dealt with this, luckily mine was dumb stuff easy to fix
too close to central air register. Rh can be super high out of register.
Oscillating fan inside tent so no eddy’s.
That’s strange. RH where I live has been between 70-100% and 90⁰+ outside the house. My GE dehumidifier keeps my lung room and whole house for that matter at 45% which is what it’s set at. My tent will go up to 51-53% at lights out but then goes back down in a couple hours. I keep my exhaust fan at speed 4 all the time with all the low vents open. The dehumidifier sits just outside the lung room door so I don’t get the heat off it in the lung room and the vent is pointed where it blows out the door from eight feet away.
I just recently had humidity battles which I was able to resolve. For your situation I had multiple questions which varied depending on your answer to the previous questions.
If you got it whipped great! If it’s still being a PITA we’re here for ya growmie, just lets us know.
If you’re in a tent. I was told to open vents at the bottom and even unzip the front door a bit. Maybe 1/4 of the way. As long as your lung room is dark of course. So far so good! We shall see, i will update in 24/48 hrs. Im in third wk of flower my baby’s came along way. Cant screw it up now!!!
Hi, Thanks for all the suggestions - here my current situation. I’ve now have the humidity in the tent down to about 10% above that in the lung room - the lung room ranges from 43 - 47 RH, and in the tent is is about 53-58, at various times.
Here’s what I played with:
Water in tent: I think this was a factor. I found some water (probably 100-200 ml) at the bottom of the tent, on some of the plastic trays that I use to support the fabric pots. I removed it, and have been careful to clean up after every watering.
Vents: I already had 4 large vents open at the bottom of the tent (2 rectangular screened vents and two 6" ports with the linings open). Right now, even with the tent door wide open for 30 minutes, the current RH in the tent (54%, right above the canopy) is 9% higher than the lung room (45%), and the RH at the tent floor is 52%, 7% higher than the lung room.
So I think there is so much plant transpiration that is hard to remove it fast enough.
Fans: I already had one fan pointing into one of the screened vents; I added another fan pointing in through one of the lower ports, but it didn’t seem to make any difference, so I removed it.
Venting into the lung room: I am venting back into the lung room. Basically, the water vapor in the tent is vented into the room, where much of it is removed by the dehumidifier and goes down a plastic tube into a basement sink below. This is working, since the lung room is much dryer (RH 43-47) than the tent, or the outside environment. I could try venting the exhaust fan in the tent out a window, but then it would be pulling air into the room from outside (which is higher RH). Also, it would take a long duct with several bends to connect to a window, and this would reduce the airflow.
As long as the fan is running you won’t get fresh air back in from venting outside which is ideal. You can add an inline back draft damper if you shut your fan down. As far as the bends you can also add a booster fan at the outside vent.
You answered one of my next questions in your reply, when you stated where you’re measuring RH.
I think you’ll be amazed how much lower the RH can be if you vent the exhaust out of the lung room.
I use a charcoal filter and vent into my attic. My lung room stays around 30% RH with the tent from low 40’s to upper 40’s, even after feedings / watering.
Our outside humidity is 85% or more. Most of the air coming into the lung room comes from the under the door, (big gap underneath) into the rest of the house. When the central A/C cuts on the tent RH can drop below 30% pretty quick. I went to extraordinary lengths to seal the lung room. Covered windows with foam board, and caulked the edges to seal. Taped off any seam in the walls, window unit A/C opened up and sealed all seams between interior and exterior functions. Sealed the tiny gap where the duct for the exhaust goes into the attic. I even had to caulk screw holes in the ceiling from where things use to hang. Every little thing I did, RH dropped just a smidge, the single biggest drop was venting the exhaust out of the lung room. I found all my leaks with a trusty bic lighter.
Before I really sealed up my lung room, when it rained my tent RH would jump into the 70’s.
BTW, I’m running two 50 pint dehumidifiers. My lung room is a tiny 8x12.
I’m sure your situation will be different as everyone’s is, but that’s my recent experience, and I’m glad to have it behind me. I’m closing in on week 10 and was freaking out about my RH.
What I meant was not backdraft, but that when air is removed by venting outside, new air has to enter the lung room to replace it. That air enters wherever there are crack around door, radiator pipes, or any other gaps. It will have the RH of the rest of the house, which is currently about 60%. So that’s more water that has to removed by the dehumidifier.
Yep, when it gets cooler here and my house A/C isn’t running the tent is in the high 40’s. It definitely effects the lung room and tent.
I did want to mention, when I mentioned in my previous post about; “after feedings / watering” the significance of that is, I’m running 9 plants in 3 gal fabric bags and feeding 3 times a day. Those girls are huge (for me) and putting out tons of water. It also applies to saying everybody’s situation is different. What I needed to do doesn’t necessarily apply to everyone else.
@1LuckyMF, It’s a Midea 20 pint, which seemed enough for a 10x12 lung room. It is continuously draining, so the capacity is not an issue. But I guess a bigger one would have a more powerful compressor. I’m going to try venting the tent out a window - if that isn’t sufficient, then maybe a bigger dehumidifier.
