How do I keep temp down when running a dehumidifier in grow room

kimpiper

Member
I need to keep the humidity down in my grow room, especially during the flowering cycle. But when running a dehumidifier, the temperature always spikes above 80°. How can I resolve this issue?
 

ProPheT 216

Well-Known Member
Use an ac not a dehumidifier and condition the air in the room the tent is in so the tent is sucking in cool 72 degree air will also keep you humidity between 45 and 60 hr through the day and night

You could increase air exchange, bigger fan and move more air
 

medidedicated

Well-Known Member
They say it removes moisture but my house thermostat reads high rh it will lower it a little but not enough for my needs. Im stuck in same situation for the summer.

When they say we feel it during these months they aint lying, its outdoor season lol.

I open door and have 16” fan blow air into the room it cools it to 75-78F instead of 82-90F literally. My rh is like 55-60.

I guess cutting holes in my door to exaust outside isnt for nothing, just not when ac is needed but I can put a pc fan in it. Im about to order one.
 

medidedicated

Well-Known Member
Well thats because I set up in small bedroom upstairs after finding I cant vent outside.. It was said its best to grow in basement but youll prob have cold problems but not hard to fix.

I invested too much but if you didnt Id highly suggest setting up in basement if you have one.
 

kimpiper

Member
I need to keep the humidity down in my grow room, especially during the flowering cycle. But when running a dehumidifier, the temperature always spikes above 80°. How can I resolve this issue?
I'm fine during veg, but trying to keep RH around 40% during late flower seems impossible
 

kimpiper

Member
Use an ac not a dehumidifier and condition the air in the room the tent is in so the tent is sucking in cool 72 degree air will also keep you humidity between 45 and 60 hr through the day and night

You could increase air exchange, bigger fan and move more air
I think you're right about needing more air exchange.
I'm already pumping cold air from AC vent into tent, but humidity still high.
I'm using a 5×5 tent with 6 inch filter and fan.
 

ProPheT 216

Well-Known Member
I think you're right about needing more air exchange.
I'm already pumping cold air from AC vent into tent, but humidity still high.
I'm using a 5×5 tent with 6 inch filter and fan.
Just about any 6 inch should pair up nice with a 5x5. What is high to you?
 

livinthadream

Well-Known Member
Have you tried just running your dehumidifier outside the tent?!
I setup in basement, vent outside house 4" inline exhaust
That's what I do for my 3x3 seems to work
I'm usually able to keep my RH around 55% with temps 71-74 when lights are off these past months
Lights on isn't an issue unless we get lots of rain
 

kimpiper

Member
Have you tried just running your dehumidifier outside the tent?!
I setup in basement, vent outside house 4" inline exhaust
That's what I do for my 3x3 seems to work
I'm usually able to keep my RH around 55% with temps 71-74 when lights are off these past months
Lights on isn't an issue unless we get lots of rain
I can control humidity in my 2×4 tent, it's when I step up to the 5x5 that I have problems. Have tried dehumidifier both inside and/or outside, but it's not enough. I think AC unit in tent may be only solution, but expense will be high.
 

livinthadream

Well-Known Member
I can control humidity in my 2×4 tent, it's when I step up to the 5x5 that I have problems. Have tried dehumidifier both inside and/or outside, but it's not enough. I think AC unit in tent may be only solution, but expense will be high.
I have watched a few videos of people using a second tent and controlling THAT environment and then sucking that into their flower tent too
 
you cant do it properly without the ac
except if you live in alaska or in a very cold spot year round

a minisplit is easy to install, they even sell small 2kw now
 

MissinThe90’sStrains

Well-Known Member
Flowering in summertime with big buds is just playing on hard mode. Youll need at least one large dehumidifier for your lung room, and possibly a small to medium sized one for your tent in addition to that. The worst time is “night”, because temps go down when the lights go off and then the humidity spikes.

If you only have one dehumidifier, you can move it into your tent right when your lights go off. They give off some heat, but with lights off itl be ok. Be sure to take it out right at lights on so you don’t fry your plants. Capacity for the dehumidifier needs to be large enough to run all “night”, and not fill up and shut off halfway through, of your humidity will spike again and you’ll have problems. Tons of air movement during the day, and dehumidifier as close by as possible at night will get you through. I literally just went though this and it sucked.
 

kimpiper

Member
I have watched a few videos of people using a second tent and controlling THAT environment and then sucking that into their flower tent too
I have tried that in my smaller tents during vegetable stage. But when it comes to a large tent during flowering, it doesn't hold up.
 

Absorber

Well-Known Member
I can control humidity in my 2×4 tent, it's when I step up to the 5x5 that I have problems. Have tried dehumidifier both inside and/or outside, but it's not enough. I think AC unit in tent may be only solution, but expense will be high.
I have two 4² tents in a bedroom(lungroom) and have this Dehumidifier it pulls room down to 38rh(even with door open ) and extraction fan on tent pulls air into tent from lung room as it exhausts air from tent .
You need a decent compressor style dehumidifier to keep up with conditions and have it outside of the tent to dilute the heat it produces .
Im in a hot climate and this methode works for me
 

kimpiper

Member
I have two 4² tents in a bedroom(lungroom) and have this Dehumidifier it pulls room down to 38rh(even with door open ) and extraction fan on tent pulls air into tent from lung room as it exhausts air from tent .
You need a decent compressor style dehumidifier to keep up with conditions and have it outside of the tent to dilute the heat it produces .
Im in a hot climate and this methode works for me
I like "dilutes the heat it produces". So your method cools two (2) 4x4 tents? I wonder if my dehumidifier can take my BR to 38% rh. I see if it does, then I'll try with my tent.
 

MissinThe90’sStrains

Well-Known Member
SpiderFarmer just released a unit that could be perfect for this. It’s a new product, and someone’s gotta be a Guinea pig, but it’s a dehumidifier that you hook up to your tent through the tent ducts, and the unit itself sits outside the tent. It’s supposed to be for the purpose of keeping your tent humidity low without having to do your whole lung room.
 

kimpiper

Member
SpiderFarmer just released a unit that could be perfect for this. It’s a new product, and someone’s gotta be a Guinea pig, but it’s a dehumidifier that you hook up to your tent through the tent ducts, and the unit itself sits outside the tent. It’s supposed to be for the purpose of keeping your tent humidity low without having to do your whole lung room.
I just checked out Spider Farmer, and they have a 32pint outside the tent dehumidifier as a new product
It is $179 including shipping.
I think I'll give it a try!
 
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