Quote Originally Posted by irydyum
If i'm reading this correct, you are planning on using an existing vent to provide cool/heat and not a return vent.

If you want to prevent any backup of odors you need to keep a negative pressure inside the growspace. The only real way to do it is with an exhaust fan, which means treating exhausted air with a scrubber. A 3x5 space doesn't require a huge fan or anything, but you must maintain a negative pressure. If the pressure becomes positive it will push out through any imperfections in the seals around your room and door.

Try as we all might, i really don't think there is gonna be a way around this one.

If you could run portable ac and have a 100% seal, that's a different story. Just a whole different set of circumstances to deal with at that point that i'm too stoned to ramble on about.

Do a search for "noobs guide to growrooms" or something close to that. Great info on room set up in there:thumbsup:
the vent is not an existing vent, it would be new. the duct work is just a few feet away in the attic, so it would real easier to add it.

i understand negative pressure very well as i have had cabinets that used a passive intake and a positive exiting chamber. in that exiting chamber was an ozone generator and a carbon scrubber at the final exit point. that technique would work for this room also i believe. and the exhaust would be into my attic.

the issue with a negative pressured room is maintaining temps in the house without drastically increasing costs. this room will be insulated and take on the temps of the house, however with a constant negative pressure what effect will that have on the house? the negative pressure would be a constant pull of air from the house (whether a/c or heat was running or not). the room would still pull it's air in from the duct work and threw the return air vent and thus from the air in the house itself. basically the entire house would become a negative pressure environment, albeit very little pressure...

the air movement through out the house will not be a bad thing, but what kind of effect on temps and thus cost will this have on my house. always pulling cool air out of the a/c system basically and pumping it into the attic. to me it would be like leaving a window slightly open with the air conditioner running...

with even a small little 90 cfm computer fan exhausting the room, the air would be exchanged about 45 times an hour. if my calculations are correct this could result in 5400 cf per hour being exhausted into my attic. so essentially in theory, i would be turning over all the air in my house every 3 hours. sounds expensive to be constantly losing all that cool air.

i wonder if after scrubbing the air if it wouldn't be better to pump it back into the room somehow ???

the second method with a portable a/c is doable. the issues i see there are:

1. room must have a tight seal to prevent odor leaking out
2. costs of running an 8 or 9 amp air conditioner


EDIT: btw, checking the thread you mentioned...
GP73LPC Reviewed by GP73LPC on . Grow Room Questions About Heating/Cooling/Odor Control I am planning on enclosing a little cavity corner in my garage that will create a 3' x 5' room. It will be rather easy to connect it to my central heat/air but i worry about odor control. i have successfully used some very small ozone generators inside cabinets in the past. those along with exhausting through activated carbon worked very well. only one strain was ever detectable by smell. with that said i will definitely be using 1 or 2 of these small ozone generators. the room will Rating: 5