Say penny wisdom, your closets 5x5x8. Thats plenty big of a space. Nonetheless what size light you gonna use. Maybe 400 watts is plenty for for the 8 plants especially since they stay small. Since heat is as issue, look into air cooled, I'm running a 400 watter in my closet 5x2x8 and air cooled works great in there. Since your in an apt. smell will be an issue. I exhaust stinky air 24/7 out of the room through a carbon can filter with a 100 cfm cage blower. The exhaust helps boost your ventilation or air exchange and when lights on helps cool. For my air cooled 400 watter I exhaust the hot air out of the room with a 165 cfm cage blower fan. Temps stay in the low to mid 70's lights on. The intake is just a nice gap between door and floor and two holes in the door. My place is shitty and doors are cheap. Nonetheless my light does exhaust stinky air beacause I have yet to cut another hole to pull in fresh air. Like if I do that the lights air never touches the room=no smell=peace of mind. Cutting holes in drywall is a snap and running 4in ducting is easy as shit. Check out my grow, need to get better picks of fans and shit but rest assured it's all there. Hang your exhaust fans on bungees, decreases noise and vibration. Good luck let me know if I can help. Oh yeah, use an HPS. Spend the money now and be happier w results.