Humidity issues (can’t get it up ) DIY ultrasonic fogger

its.always.420

Well-Known Member
Would I be better off humidifying the room the tents sit in with a larger fogger and control with a humidistat instead?
Yes.

Problem is, by exhausting out of the house, you are constantly pulling in cold dry air from outside. The air you remove has to be replaced, so you're going to be humidifying outside air just to put it back outside again? Going to take a BIG unit to humidify the entire outdoors !

You said you are having heat issues, yet running a heater in the room?

Its winter so you want to keep the heat indoors instead of wasting it. You could try venting back into the same room, and running a dehumidifier. This may eliminate the need for a heater. You said you tried this....is your room not connected to any house hvac? Seems odd the heat builds up that badly.
Mabye crack a window too? It would passively let some cool air in without drawing a negative pressure.

Also the ultrasonic humidifiers drop air temps a few degrees so that could help you.
 

1212ham

Well-Known Member
Yes.

Problem is, by exhausting out of the house, you are constantly pulling in cold dry air from outside. The air you remove has to be replaced, so you're going to be humidifying outside air just to put it back outside again? Going to take a BIG unit to humidify the entire outdoors !

You said you are having heat issues, yet running a heater in the room?

Its winter so you want to keep the heat indoors instead of wasting it. You could try venting back into the same room, and running a dehumidifier. This may eliminate the need for a heater. You said you tried this....is your room not connected to any house hvac? Seems odd the heat builds up that badly.
Mabye crack a window too? It would passively let some cool air in without drawing a negative pressure.

Also the ultrasonic humidifiers drop air temps a few degrees so that could help you.
OP has hot water heating. I'd try to determine why the room and basement are warmer than other parts of the house and look for a way to exhaust to another room. I solved my humidity problem by running my exhaust into the cold air return in the grow room.

I'll try to get back to this later, got to get my butt moving and transplant....
 

BigGreenThumb

Active Member
Yes.

Problem is, by exhausting out of the house, you are constantly pulling in cold dry air from outside. The air you remove has to be replaced, so you're going to be humidifying outside air just to put it back outside again? Going to take a BIG unit to humidify the entire outdoors !

You said you are having heat issues, yet running a heater in the room?

Its winter so you want to keep the heat indoors instead of wasting it. You could try venting back into the same room, and running a dehumidifier. This may eliminate the need for a heater. You said you tried this....is your room not connected to any house hvac? Seems odd the heat builds up that badly.
Mabye crack a window too? It would passively let some cool air in without drawing a negative pressure.

Also the ultrasonic humidifiers drop air temps a few degrees so that could help you.
I know exhausting out makes things tougher, just figured since the air I’m pulling would be coming from the doorway leading to the rest of the house and not the cold dry outside air, that I might be able to at least control it a LITTLE.

I have a heater in the room really for lights out, I’ve read that large temp swings more than 10 degrees can cause pwm. Lights on runs room 82-85 and I keep it around 72-75 during lights out, rather than the 68 or so with no heater.

Where I’m venting currently is unfortunately the ideal spot for my house just obviously not the best for the grow as I’ve found.
 

myke

Well-Known Member
Im same,so cold my furnace runs, humidity is down,don't chase it, live with it.
 

madvillian420

Well-Known Member
Hey RIU… so after a constant battle the last couple of weeks, I’m here for some help and advice. As always it’s much appreciated…

Where I’m at it’s cold and very dry out. Im having a hard time keeping my tents humidity higher than MAYBE 35-40%
Same. i made a similar post many moons ago, some reputable folks like Renfro chimed in and all said the same thing: ignore it. better to have low RH than high RH, especially in flower.
 

BigGreenThumb

Active Member
OP has hot water heating. I'd try to determine why the room and basement are warmer than other parts of the house and look for a way to exhaust to another room. I solved my humidity problem by running my exhaust into the cold air return in the grow room.

I'll try to get back to this later, got to get my butt moving and transplant....
the room and basement have always been warm, there are low ceilings and all of the heating pipes for the entire house are fed right above…
Tell me about your exhaust setup… do you basically recirculate your exhaust air back into the rooms fresh cold intake air? Kind of mixing it or am I way off lol
 

BigGreenThumb

Active Member
I’m going to stop chasing my tail, honestly I think a big part of my issue is I’m using a pretty powerful LED for my size space. Also being the first time using LED and I got fixated on the whole VPD bs and trying to get the right temp and humidity because from what I understand plays much more of a role than when using good old MH or HPS. There’s an obvious learning curve.. My buddy is growing the same cut as me and his looks great, mine are all burnt leaf tips and droopy, not looking too happy, both were fed basically the same. Environments were similar, the only difference was his started under floro and moved to under MH.
 

1212ham

Well-Known Member
I’m going to stop chasing my tail, honestly I think a big part of my issue is I’m using a pretty powerful LED for my size space. Also being the first time using LED and I got fixated on the whole VPD bs and trying to get the right temp and humidity because from what I understand plays much more of a role than when using good old MH or HPS. There’s an obvious learning curve.. My buddy is growing the same cut as me and his looks great, mine are all burnt leaf tips and droopy, not looking too happy, both were fed basically the same. Environments were similar, the only difference was his started under floro and moved to under MH.
VPD bs?
 

Billy the Mountain

Well-Known Member
Portable misting systems cool the air through evaporation in the same way. As the fine mist shoots out from the fan, some of it simply disappears. The mist that disappears has evaporated. Since this transformation requires heat, the molecules pull the heat they need from the air around them, leaving the air cooler.
I routinely put a small ultrasonic humidifier in a 2x4 tent during early veg. Its a 60w model. I can watch the humidity rise from 40% to 60% and the temp remains constant. My data logs confirm this.

My guess is whatever minimal cooling effect is present is offset by the 60w of heat the humidifier generates.

Evaporative humidifiers can cool in a hot, arid environment (i.e. swamp coolier), ultrasonic humidifiers in a more humid environment don't seem to cool enough to overcome the heat they generate.
 

1212ham

Well-Known Member
the room and basement have always been warm, there are low ceilings and all of the heating pipes for the entire house are fed right above…
Tell me about your exhaust setup… do you basically recirculate your exhaust air back into the rooms fresh cold intake air? Kind of mixing it or am I way off lol
Search cold air return. They recirculate air back to the furnace, i have one in every room. The tent exhausts to the cold air return in the room.
 

BigGreenThumb

Active Member
Search cold air return. They recirculate air back to the furnace, i have one in every room. The tent exhausts to the cold air return in the room.
lol I’m an idiot.. that makes sense. I didn’t put the 2 and 2 together that it’s a forced air system. I have a hydronic system with radiators and baseboard so that wouldn’t work for me.
Just thinking outside the box… this doesn’t cause any duct issues with the added humidity?
 

1212ham

Well-Known Member
lol I’m an idiot.. that makes sense. I didn’t put the 2 and 2 together that it’s a forced air system. I have a hydronic system with radiators and baseboard so that wouldn’t work for me.
Just thinking outside the box… this doesn’t cause any duct issues with the added humidity?
It's fine, less humidity than many summer days.

I've done hot water.... Cover any baseboard in there. Insulate pipes starting at the boiler. Wrap that accumulator, they're radiators in disguise!

I'd look for way to get some air circulation with another room/area. Is the room in an unfinished basement? Door open?

Maybe recirculating in the room can work if you bring in a little outside air with a small fan?
 
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