my first grow i had no ventilation in my growroom. 6x6 walkin closet. i would leave the door open so the air could get in, from the ac in my room. i had the window covered, but the slides on the side of the ac are kinda transluscent. the sunlight diffused through it and got into my room, it wasnt a ton of light but it was enough to do the deed, i figured it was ok cuz i had my room mostly partitioned off to just a small area for my one plant. it was almost a grow coffin in my closet. hope that answers your qestion.