Well, I tried to post this response like 45 minutes ago or whatever but it didnt upload. Here it is anyway:

I am under the impression that a "sealed room" is just that - sealed. No intake or exhaust. The room simply uses CO2 to give the plants what they need and uses circulation fans to keep the air moving. Check out the Tranoble's thread in the Growroom Setup section.

Like I said, this is just what I have come to understand. I have not read the thread fully myself, and now that I think about it, I wonder how he keeps the heat down. I know that CO2 is absorbed better at higher temps, but can he keep it that low? I'm sure he has a way! Go check it out.

TGF