Need venting advice for my 4x4 tent

Hi all, I’m new to this site. Although I have been a patient and caregiver for 12 years now, I had to stop growing for the last 3½ years and am now getting up and running again with 3 beautiful White Rhino and 1 Purple Haze. I am new to utilizing a tent as I was growing in a specifically designed basement grow area prior to now. The problem I’m having at the moment is humidity control in this tent. I was having an issue with humidity getting up to between 89-92%. I’m not panicked just yet as I am still in veg until the 1st when I will switch over to flower. I have a 440 cfm inline exhaust fan with a carbon filter pulling air out 24/7 for now and pumping it out into my bedroom which thankfully is keeping humidity levels between 50-60% for now, but that is still too high for flower. Here’s my question. Is it possible to vent into the cold air return duct? There is one right above the tent and it would be an easy transition. It would also keep any odors from being put right out the window which would happen if i was to vent out the window. I wouldn’t want to do anything to disrupt the flow of air from either my water heater or my furnace. Would venting to a cold air return vent cause either of these problems? Thanks for your help everyone.

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Hello and welcome!
Where you vent your exhaust to should not effect any of your systems. I am assuming that that you are currently venting into the room containing your tent?
One point to remember is that your carbon filter will remove all odours - so out the window would also be fine - possibly not so discreet.
It is more about removing the moist air from the room - in that respect - you are on the right track. :sunglasses: :+1: :v:

yep into the room the tent is in (my bedroom) took a friend and fellow grower to remind me yesterday that if I’m venting into the room the tent is in and ALSO drawing air from the same room that I might be inadvertently adding to my humidity problems. I’m pumping the humid air out, only to suck it right back in again🤦‍♀️. I do have another 6"inline coming tomorrow that I will be putting on the bottom level of the tent to pull fresh air from the room into the tent. Watching closely for changes and hoping to find the correct remedy by Wednesday. I know i have a little wiggle room with the humidity issue, but I also know that will only be for about the next 10 days or so. Once I hit that 10 day mark in flower, I better have this humidity problem under control. I suppose I will get up there tomorrow and give the return air duct a go. Thanks for your advice.

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Ok cool - I had it right in my head.
You do get a bit more wiggle room than the 10 day mark. It’s more about once the heads start to fatten up and sweat.
On the subject of sweat… this is in your bedroom. Be sure to keep all perfumes, aerosols, strong scents WELL away from the inlet - otherwise you risk contaminating the ‘wicked bud’ smell we all aim for. Just a thought - one to be considered. Inlet filtration would change up the inlet arrangement drastically. :wink: :sunglasses: :+1:

Could you explain what you mean by your last sentence? I’m just getting back into the swing of things after being out of the game for awhile. Do you think the addition of the new 395 cfm 6" inline will help in reducing the humidity in the room? And should I leave the intake and exhaust running 24/7. In my previous growing experiance I didn’t have this issue. It was a LARGE grow area and I simply had a house dehumidifier running in the basement.

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Of course.
I’m not sure your inlet fan is required firstly. But I think a bigger concern in your bedroom is contamination of the air by chemicals from perfumes, aerosols etc. You either need to get them out of the space where your inlet is - OR filter your inlet to remove everything from dust to chemical odours/ perfumes. That can get very tricky, expensive and require a different fan/ filter arrangement.
Noise may be another issue in your bedroom - fans running while you sleep could be an issue.

I hope that makes more sense? :+1: :sunglasses:

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It does and thanks. No perfumes or air fresheners anywhere near the tent. Actually not in my bedroom at all, that stays in the bathroom. The only contamination air wise they see is when i make them cannibals and smoke while om working on them…lmao the sound from the venting doesn’t bother me. I sleep with ceiling fans and window ac units on high. I have considered purchasing another carbon filter to attach to the intake fan and filter the air going in. I just didn’t think it was really a necessity. Should I be reconsidering that?

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Ok awesome. Providing you keep the scents out - your only real contaminant will probably be dust. It is advisable to minimise that. But you wouldn’t need to go to the extent of a carbon filter on the inlet. Something like the grey filter media from your a/c return works well - minimal pressure drop. Or you could just put an old stocking over the inlet duct as a minimum - that will keep any invasive bugs or critters out (not sure where you are in that respect).
Best of luck! Always around to help where I can - or get others involved easily. :+1: :sunglasses:

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Welcome ! I agree with your friend exhausting hot stale air in the room you’re pulling fresh air from can create a problem. The easiest way I found to control the inside of the tent is to control the temperature and humidity from the room you’re pulling the fresh air from. Just my thoughts good luck.

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The cold air return is already drawing the air from your room and just recycles it through your HVAC system. So venting your tent into the cold air return makes it more direct than it is now. I have a 3x3 which vents back into an 8x14 enclosed space that contains the tent. If humidity is an issue (mostly seasonal) I use a dehumidifier to help maintain the humidity in the space. It does increase the ambient temp slightly.
I use a 6" intake fan also. Since you have grown before, you know light control is a must and some sort of prefilter is recommended. It is amazing what would otherwise get sucked into the tent. This is what I did to take care of both items. The fan is in the box and is insulated for sound.


Any filter material will work.

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