I use T5 ! 12bulb overhead and 1 8bulb on the wall go to my galleries and yes heat can be an issue! I have big intake and fair size cam fan combo out take and a medium size circulation. 2 average a/c wall units in my place, 1 in my room and one in the front of the place. run regularly on thermostat set on auto at 70. so nice inside during summer, here down south but power can run alittle high but nothing you wouldnt see in any other home during the summer. they work great for me so far with one grow done and working on second. As you can see light is not a problem I have a total of 100,000 lumens glowing a 3.5x6x6 closet space I designed,. Total beginner BTW! I did do lots of research, saving, designing and learning about growing before I even started. Good luck to you and look forward to seeing your reults,