Thanks to the responses from people who know about sealed grows or have experience growing in this way. As for the people who said I 'Need' fresh air and to vent, I don't need fresh air I need light (lots of), co2 (without exhausting it outta the room and wasting it), and temp/humidity contral. These are the requirements for a plant aswell as food of course. The fresh air you stated I need is to replenish the co2 in the air. If I'm providing 1200-1500ppm of co2 instead of the normal amount of co2 in the air (roughly 300ppm) then it is counterintuitive to vent as it'll drag my co2 out. Please read up on ceg or sealed grows. I was asking how to decrease the humidity and/or control it more efficiently not wether I need to vent or not. Devolve how quiet is that dehuey you mentioned and how hot does it run? Looked into one but can imagine it bein extremely noisy?Superstoner cheers for your input. I have an air con (portable) but its a single hose outlet and does actually drag some air out of the room which is obviously no good in this situation. The temps are fine it's just the humidity I'm having problems handling.