If found that you can fuck up a bud if your flower is actually pressed onto a tube, but I dont worry about leaf burn. The leaves will burn/bleach out if left on contact, but it wont stress the whole plant like a hot HID bulb can (I crisped 3 ft worth of sativa my first grow when I thought a 500w HALOGEN light would be good to grow with, yeah lol I know) HID heatstress/burns can damage right down to your babies soul! no recovering from that. But the T5 burns Ive had to my foliage is basically just a white strip across a fan leaf where the contact was made, but the leaf structure is not damaged (the tip of the leaf will remain green where there is a bleached white strip right across it) Ive even found that leaves that are bleached when the plant are young, actually repair themself (or seem to at least, young leaves continue to grow larger and the bleached strip seems to shrink in turn). The point is, T5's operating temp is abt 95deg I think, and HID's are in excess of 150deg. Im only concerned for top colas growing up into the bulbs, otherwise I dont worry about jack
love my T5's! 29 tubes running as of today, soon to be 37!!!! oh and my electricity bill last month (with a 14kBTU 1350w AC running 24/7, in a 2story home) ... = $84!!!