Are dehumidifiers only making sense in a sealed room?

[HendrikOl]

Hi,

currently I am fighting high humidity. The outside rh is high due to plenty of rain (70-90%), grow room rh is just 5% more, so I have enough ventilation. It was fine during vegging but it obviously sucks during flowering as I already had to cut off two colas due to bud rot. As a short term solution I placed another two fans in the grow room which are blowing at the canopy.

However I was thinking if it makes sense to buy a dehumidifier. I am limited on the energy I can use and hence every additional item which consumes energy is not ideal for me.

Furthermore I doubt that using a dehumidifier in a room which is not sealed makes much sense. This is because of the dry air exiting the dehumidifier will be sucked out shortly after by my ventilation. I need to move at least 300m³ of air per hour out of my grow room. If I buy a humidifier which can support 300m³ per hour it would therefore run constantly?

Also I read about creating a lung room and placing the dehumidifier there, but this solution will only move the heat away from the grow room.

Furthermore how noisy are 250-350W dehumidifiers? The quietest I found have around 40db? Can they be used at night in an apartment or do I have to worry that my neighbours could hear it?

 

[smurfin'herb]

Are you running an air conditioner? They dehumidify air as they cool usually. Some even have a dehumidify function built in. Good luck.

 

[Snow Crash]

While they are pretty much only used in enclosed environments greenhouses do employ them. But the issue you have is that the dehumidifier that can handle the needs of your environment, with the air exchange, will cost you thousands of dollars. You can spend a couple hundred on a low efficiency model but, like you said, the power available really just isn't going to cut it.

Can you maybe adjust your grow space so that instead of exchanging air with the outside it pulls it from inside the house? I used to have a 5x5 tent in a place that was about 900 sqft. In the winter time I just sent the ducting from the heat out of the bedroom and into the hallway where I could use it. This saved me money on my heating bill and allowed the RH to be a little lower. Being that I was in Portland OR, you can bet it was a little wet outside that winter. Another way would be to run the exhaust out to the window and run your intake from another room inside of the house that you can keep better control over the environment. It's known as a "lung" room and can build a drier buffer between the outside world and your grow space.

Get creative, think outside the box, and you might have somewhere else to exchange that air which would make a Dehuey much more viable.

 

[Granger2]

AC's dehumidify, but not enough, IME. Only dropped my humidity about 5% points when I dropped my AC unit thermostat from 76 to 72 degrees. Down from low 70's to about 66% just isn't enough. I run a dehumidifier to get it to where I can have a healthy crop at 50% humidity. Good luck. -granger

 

[shaggyballs]

I say run both air and dehumidifier.
If you run a dehumidifier in a small room it will get hot fast!

shag