Vegg room, moved upstairs

I have a flowering room in the basement, i think I'll keep it there, but the vegg room i moved up stairs to a bedroom i don't use it has CFL lights, power intake, and power exhaust with a fan. My question can i have the exhaust blowing out the top of the unit, or ducked out to the living room, i could conceal the hole in the wall with a cold air return filter, so you wouldn't see it. I plan to have yeast-sugar-water for CO2, but the stale air i don't know about. The flowering room i have it ducked right into the chimney, not that it matters, but this room is right on the street, so i can't have it going outside. Any ideas what to do??????????

I had another thought, ducking the exhaust into the attic, but cold air being heavier then warm don't want all the cold going into the room, thats why i moved it upstairs.