Dehumidifier Placement - exhausting grow tent outdoors

SpawnOfVader

SpawnOfVader

Well-Known Member
I've got a mini-dehumidifier and I recently switched my setup to exhaust outside. (intake is run next to the AC vent)

trying to think of the most effective place to put the dehumidifier. Since the air inside the grow tent is exchanged so fast, would it make more sense to put it outside the room near the intake? At least that way it also dehumidifies the source of the air/room around it instead of just trying to keep up with the airflow out of the tent....

Current setup for ventillation:
6 " intake/exhaust/carbon filter/fan (running at minimum power)
2x oscillating fans (mounted from top of tent on low power)
knockoff EVA-DRY 1100 running off inkbird humidistat switch
 

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Super rough math-
360 CFM fan (advertised) running 24/7
About 110 CFM lost due to carbon filter
Another ~50 lost due to length of ducting and turns
Running at roughly half power... so maybe 100-120 CFM actual airflow and I've got a good amount of negative pressure built up so it might not be that high.

54 ft3 in the grow tent so it should be swapping the air at least once if not twice per minute.
 
SpawnOfVader said:
I've got a mini-dehumidifier and I recently switched my setup to exhaust outside. (intake is run next to the AC vent)

trying to think of the most effective place to put the dehumidifier. Since the air inside the grow tent is exchanged so fast, would it make more sense to put it outside the room near the intake? At least that way it also dehumidifies the source of the air/room around it instead of just trying to keep up with the airflow out of the tent....

Current setup for ventillation:
6 " intake/exhaust/carbon filter/fan (running at minimum power)
2x oscillating fans (mounted from top of tent on low power)
knockoff EVA-DRY 1100 running off inkbird humidistat switch
Click to expand...
Little point in a tiny dehu like that with your extraction fan running.

You need a bigger one or a closed environment set up.
 
oill said:
Little point in a tiny dehu like that with your extraction fan running.

You need a bigger one or a closed environment set up.
Click to expand...
So daytime humidity stays below ~60-65 normally. It's high for flowering but this is the first time I've even tried to manage humidity since it stays constant in my house and I've never had any major issues. I'm more worried about it spiking at night... maybe just stick the extractor fan on a timer and shut it down at night/leave the dehumidifier running?
 
Gwhiliker said:
more airflow=less mold chance if you are stuck with higher rh
Click to expand...
K well with that in mind the fan is up to running at like 75% power and the dehumidifier is just out side of the intake now. Probably will invest some $$ into a larger dehumidifier for the room eventually. On the plus side- I moved the humidistat switch outside of the grow tent and ran the sensor in the intake ducting so I've got a nice easy way to monitor the tent's humidity at canopy level now. (all my sensors/displays are in the grow tent so I normally just watch the min/max)

I really need to get an automation/monitoring system up and running soon.
 
just try to achieve a stable temp instead of having to drop and raise it with fancy controllers and stuff lol
 
Gwhiliker said:
just try to achieve a stable temp instead of having to drop and raise it with fancy controllers and stuff lol
Click to expand...
Yea my biggest problem is to keep the temp down during the day cycle I need to draw from the AC unit but I live in the south the AC is basically running 24/7 so night temps in tent go down to like 68

*fingers crossed once I redo my attic vents next week the night temps stabilize and the AC won't need to run 24/7
 
Gwhiliker said:
dont worry about night just always keep ur exhaust fan on 24/7 probably on max on that little guy
Click to expand...
So it's a super humid (~93% day outside) and inside my tent even with the AC running it was sitting at 84 RH all day. I decided to experiment and removed the cloth pre-filter from my carbon filter and closed up the tent. Ambient humidity in the room is the same but the tent dropped 4.5 RH in the first 5 minutes and has stabilized there.

I didn't realize those restricted the airflow so much. Is the main idea to prolong the life of the carbon filter? If so I'll probably just leave it off and replace my filter more often for the increased airflow.
 
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