in my experience, my 400 raised the temperature in my closet about 8 degrees. professional ventilation is always awesome and better but youd be fine even with a regular old oscillating fan moving the air around. in the winter its great because turning the light on doesnt even really raise the temperature if i leave a window cracked.
oh yea also, do you rent or own? because if you rent you should definitely make sure that you are the only one with keys and access to your apartment. maintenance guys can and will pop in randomly, and dont think they wont poke around if they smell or see something fishy. and dont forget about murphy's law.

anyways, i have a question kind of related to this now too. ive never used a digital ballast, but is it true that they dont take to voltage fluctuations very well and this can cause them to break?
mushaboom Reviewed by mushaboom on . 400w to much for apartment? Im gonna be doing my first grow in my apartment closet but i was wondering if i should Go with a 250w or 400w hps/mh combo. Would the 400w be suspicious? And how much heat do these bulbs really produce, i have a pretty open closet and dont know if i need to invest in an air coolable system or even go with a 4 bulb T5 system supplemented with 4 cfl's on the side during flowering?. Rating: 5