Dehumidifier Question

[primitive]

Hey people,

In my new setup I'm running into RH problems for the first time, and before getting a dehumidifier there's a thought that's been bugging me:

If I'm exhausting the air from the room 24/7, won't the dehumidifier just be lowering the RH for a couple minutes before new humid air is brought in? It's been raining a lot so my intake air is 80's-100 humidity. I also just switched from two to five gal. buckets, so there's more moist material in the room. So, it seems to me like a dehumidifier would only work in a sealed room setup but I don't really know, has anyone used one in a vented room w/ success?

And of course any other solutions are welcome.

 

[dirtyolsouth]

Hi,

They do help even with ventilation... Can you have the dehumidifier in another room that you can pull the dry air from into your grow space? A steady feed of less humid air will definitely help you control things indoors... And imho dehums are only good from fall til spring around here when temps are cool cuz they do create some heat as a by product...

Good Luck!

 

[jmansweed]

I think your right. My exhaust is auto w/ a certain temp so when it's off my dehumidifier kicks on. Dehumidifiers heat things up so it may not be your best option. Air conditioning?

 

[primitive]

Hi,

They do help even with ventilation... Can you have the dehumidifier in another room that you can pull the dry air from into your grow space? A steady feed of less humid air will definitely help you control things indoors... And imho dehums are only good from fall til spring around here when temps are cool cuz they do create some heat as a by product...

Good Luck!

Hmm, I'm not sure I understand the question. I don't have any less humid rooms that I can use to draw air from, or do you mean use a dehumidifier w/ a duct exhaust in any room vented into the flower room?

 

[primitive]

I think your right. My exhaust is auto w/ a certain temp so when it's off my dehumidifier kicks on. Dehumidifiers heat things up so it may not be your best option. Air conditioning?

Heat isn't an issue right now; what kind of unit do you use that switches the exhaust and dehumidifier? Some kind of thermostat w/ alternating power sockets?

 

[BBFan]

I use a regular old dehumidifier in my grow room. I like to keep my rh below 35% during flower, preferably down around 28%.

Yes, it runs often, sometimes almost non-stop (I grow in my basement and at this time of year it's still a little damp- isn't as bad in the cold of winter with the furnace running).

The biggest thing I have to deal with is the heat the dehumidifier kicks off like JMansweed said. It's a challenge to keep the temps down. Good exchange of cool air does the trick for me.

But without it and my rh would be 50% still. That's fine for vegging, but in flower IMHO it's too damp.

Happy Growing!

 

[monkeybusiness]

I use a regular old dehumidifier in my grow room. I like to keep my rh below 35% during flower, preferably down around 28%.

Yes, it runs often, sometimes almost non-stop (I grow in my basement and at this time of year it's still a little damp- isn't as bad in the cold of winter with the furnace running).

The biggest thing I have to deal with is the heat the dehumidifier kicks off like JMansweed said. It's a challenge to keep the temps down. Good exchange of cool air does the trick for me.

But without it and my rh would be 50% still. That's fine for vegging, but in flower IMHO it's too damp.

Happy Growing!

So out of curiosity, is it like my water chiller where the heat comes out an area on the back that can be creatively vented out of the room w/out affecting the rest of unit? I've never looked at one close so i don't have a clue how it's set up.

 

[jmansweed]

Hey Primitive ........Green air products - monitors my temp and humidity and operates everything automatically, best product I invested in, also connects to my digi co2 meter and dispenses it accordingly.

 

[BBFan]

So out of curiosity, is it like my water chiller where the heat comes out an area on the back that can be creatively vented out of the room w/out affecting the rest of unit? I've never looked at one close so i don't have a clue how it's set up.

Hello there Monkeybusiness-

Don't know whether to laugh at your avi, or just look away. Something about it just seems wrong! j/k

My dehumdifier is an older unit (got to be over 15 years anyway) so I don't know if dehumidifier technolgy has changed...

On mine the air is drawn into the back of the machine- is somehow warmed up, then passes over some coils (which probably have a refrigerant in them to be cool which causes condensation on the coils) and then comes out the front of the unit- which is the drier (and noticeably warmer) air.

I would think if you vented that warmer, drier air, out of your space, you would be defeating the purpose- unless the make-up air is dry. But if that's the case, you probably don't need the humidifier anyway.

Hope that's what you were asking. Happy Growing!

 

[monkeybusiness]

Hello there Monkeybusiness-

Don't know whether to laugh at your avi, or just look away. Something about it just seems wrong! j/k

My dehumdifier is an older unit (got to be over 15 years anyway) so I don't know if dehumidifier technolgy has changed...

On mine the air is drawn into the back of the machine- is somehow warmed up, then passes over some coils (which probably have a refrigerant in them to be cool which causes condensation on the coils) and then comes out the front of the unit- which is the drier (and noticeably warmer) air.

I would think if you vented that warmer, drier air, out of your space, you would be defeating the purpose- unless the make-up air is dry. But if that's the case, you probably don't need the humidifier anyway.

Hope that's what you were asking. Happy Growing!

Ah, so the dry air it puts out is also warm. I didn't know if the process was done and different air that was warm was a byproduct and exhausted somewhere else. Thanks for the reply!

 

[primitive]

Has anyone had any success w/ the various DIY dehumidifiers? Some seem like they might work okay, but I'd rather not run around finding knick-knacks to build something without knowing if it'll do squat.

Also: I hooked up my AC unit and ran it in dehum/fan mode for a day, it lowered it from RH80 to RH67. This is still to high obviously, but worse it seems my AC uses the same high power whether the compressor is on or not, because it tripped my fuse(as the AC function did, which I haven't used since first trying it).

Could it help to put my exhaust on a timer? Like 15/15, let it warm up hopefully get rid of that humidity periodically?

 

[dirtyolsouth]

Hmmm....

What I was getting at above is if you have ie another room that you could operate a dehumidifier in and you can pull the dryer air into your room with ventilation? I grow in my closet... From fall until spring I run a dehumidifier sometimes and I pull cool air into my bedroom from outside to balance out the temps... but most of the time the outside air is fairly dry... So the air that gets pulled into the closet gets cooled and dehumidified in the outer room first...

From spring til fall I use a window a/c unit... but this is the south and I can't pull my RH below 45% even with my a/c unit... and I gotta watch for bud rot like a hawk... I've rarely ever had any problems flowering as long as I can get the humidity around 50% or below... Less WOULD be nice but you can only do what you can... Good Luck!

Peace!

 

[primitive]

OK, it's time to actually buy a unit now. My first harvest in this new space is done and the GDP got hit heavy by mold(strangely, the mold barely touched the Afgoo and Blue Cheese right next to it). I saved the rotted buds I picked off throughout the grow for bubble hash and in total I lost about 1 1/2 oz.

SO, the question now, is can someone recommend a good model for a vented room? I've done searches and can only find solid recommendations(from growers) for powerful $1200 units used in sealed rooms. I need to keep it to around $400 or so.

And here's some bud porn of the GDP and Blue Cheese. Thanks for reading

 

[nouvellechef]

I paid $200 at the depot. You can see it in pics. Sits atop a 18gal rez. keeps the room at whatever you want. I run 40% in a 10x12.

 

[primitive]

I paid $200 at the depot. You can see it in pics. Sits atop a 18gal rez. keeps the room at whatever you want. I run 40% in a 10x12.

I saw it in your pics, any idea what brand it is?

 

[nouvellechef]

GE, just set it and forget it. One of my best investments for sure.

 

[legalize_freedom]

I got mine at a Habitat for Humanity store, it's like a goodwill, or Salvation Army, only they carry building materials, and household appliances etc. it was like 10 or 15 bucks. As far as the tents, and such I priced them also, and decided to build my own enclosed room, that I can tear down in about 30 min. I probably have 100 bucks or less in lumber, paint, and hardeware. (not counting fans, lights etc) It is only 4x4x6...but still a heck of alot cheaper than a tent.

 

[zem]

hey there primitive, i got a wood's dehumidifier (canadian brand) it does the job very well BUT, its problem is that it gives out noise and heat, i wish i got me a split A/C unit instead, IMO get A/C it has dehumidifier and A/C and its noisy compressor can be placed outside the room...

 

[primitive]

GE, just set it and forget it. One of my best investments for sure.

I found what looks like yours and it got great reviews, but Home Depot doesn't have GE dehumidifiers anymore, nor did any other store I called. I ended up with a 65 pint LG. I decided I'll give it a tryout, if it doesn't cut it I can return to the drawing board.

I also put my exhaust on a 15 minute on/off timer to try to give the thing a chance to work on some still air periodically, am I thinking in the right direction here or is it possibly more likely to just cause stressful fluctuations? I've been running my exhaust 24/7 and it's still just hard for me to imagine a dehumidifier having any effect on a constantly exhausted room.

 

[primitive]

hey there primitive, i got a wood's dehumidifier (canadian brand) it does the job very well BUT, its problem is that it gives out noise and heat, i wish i got me a split A/C unit instead, IMO get A/C it has dehumidifier and A/C and its noisy compressor can be placed outside the room...

Thanks for the input, in the summer I did use a portable AC, 12,000 btu's I think. I think it isn't quite powerful enough for my room, it didn't have a tremendous effect but it brought temps and RH down to barely acceptable levels.

Where I live now it's cold in the winter though, cold enough to have a heater on in the flower room during lights out, so the AC isn't really an option. So I hope whatever dehumidifier I end up with gives off lots of heat, then I can nix the heater at night