T5 lamps operate at 95 degrees. That is the optimal operating temp to get the best light efficacy. your fixture probably has a built in heat sink to help dissipate heat. DIY fixtures to not have metal heatsinks and must be cooled at the ends to produce the most efficient light. so you do have heat, its just being dealt with more efficiently.
Quote Originally Posted by manhorsedog View Post
i am going to need you to explain this because i dont understand.

My t-5 fixture puts out NO heat, i mean like NONE. You can touch the top of the fixture after running for 10 hours and its room temp . Not to mention my tank stay at 77-78 all year around with my house temp at 75.

What kind of t-5 did/do you have? i have noticed PC's to get hot and on my biocube they keep my temp at 80