do u keep ur exhaust fan on all the time?

[chongsbuddy]

do u have to continually run an exhaust fan,or can you just remove the stail air every hour or so,whats the best way to maintain temps when using an exhaust fan?i have a 4 by 7.5 by 6.5foot grow space,vented to the attic.i have a 290 cfm fan with a 8 inch carbon filter.i want to use co2 so i want to maintain a constant temperature im my room,any suggestions to piull this off?i am running 2 1000 watt hps bulbs.

 

[habeeb]

running co2 changes things, which I know nothing about. I'll let someone else answer

 

[ItsAllOver]

If you are going to use CO2, you need to look into sealed rooms. So the answer is that you probably are not going to exhaust at all.

 

[PeteWeedSeed]

My co2 room works like this
Lights on - intake/exhaust vents close, co2 turns on
lights off - intake/exhaust vents open, co2 turns off
So during the night cycle when plants don't use co2, they get fresh air from outside. During lights on, co2 is kept at 1500 and just circulated around with fans, and cooled by A/C. No air leaves or enters the room during lights on.

Simple system... just expensive parts to make it work.

 

[bterzz]

Wow Pete, that is a really great idea..

i'm gonna use it. Thanks.+rep.

 

[JackTheGrower]

Another point of view..

I grow soil so even at night there is a need to keep the transpiration going..

There is evaporation and convection..

It's a good thing for me, to keep the fan on all the time.. 24/7 that's why i bought an 8 inch hurricane oh man what 6 years ago.. It's still going just fine..

The important thing is to clean the blades at least 4 times a year..

I know it's all good when the plants emit that final burst of scent at lights out.. I think the stoma(s) shut quick as the temps drop. These are cherry.. The ones before were strawberry..

So for me the odor control has to be state of the art.

I vote for 24/7 to keep the air moving..

Jack

 

[Dhude]

My exhaust is scrubbed, so yeah it's running 24/7 to maintain neg pressure, but I have it on a temp based speed controller with an idle setting. Quantem and Phason are two good ones with several models.

Below your set point, runs at wherever you set idle (20% in my case) from set point to 6deg above it slowly ramps up fan speed until it is running max at setpoint+6. So at night, it's always running 20%, at lights on as the room heats up the fan slowly picks up speed.

 

[bobblehead]

Yeah, exhaust 24/7... unless you're not worried about someone smelling your grow.