My work in progress...

[Coldpressed]

the room has air conditioning so keeping it cool in Summer will not be a big issue.

With all points duly considered, I think I'll stick to the small oscillating fan I have coming, artificially augment the Co2, and vent to the attic. Thanks for the input!

[smoknjoe]

Glad we could help. Best of luck to you, friend!

One more thought....

Wouldn't there be MORE CO2 inside your house than outside? Think about it, the air thats inside your house came from outside. But when you sit inside your house breathing, you are increasing the CO2 content.

[chisme]

i gotta say it turtle420 is 100% correct in my opinion

[chisme]

turtle could u gimme a email i need a little help chisme121athotmaildotcom

[justaseed]

i never used outside air and i had excellent growth and yeilds(close to a lb from a 400hps). i am sceptical about using outside air. too many variables. if you use air from another room it will always be relatively the same temp, in the 70's usually. but if you live in a climate like mine and use outside air , in the summer you will be sucking 100+ degree air into youi grow on some days and in the winter you could easily freeze you plants when the intake is taking in air that can be below zero. also wouldn't there be a higher co2 content in the house with everyone breathing, pets, etc. outside there is alot more volume of air to disperse this co2. i could be wrong about there being more co2 indoors but it makes sense to me until someone says otherwise with a good explanation. i just noticed the last poster said the same thing so there has to be something to it.