i use t5's as well, but they are 4ft and 6 bulbs in the ballast. i can get within a few inches if i make sure my fan is on and the house is at a good temp. but iam finding that now that summer is here, if the bedroom gets above 75, its guarenteed that they will be too hot within 3 inches. i had to move them to around 6 to compensate (our house doesnt have ac). i also cant afford or handle the heat of an HPS so iam using these through flower as well.The lights you're using are most likely t12s. They don't generate much heat. I use t5s for clones at about 2in at 2 weeks old. t5s cast more heat than t12. Never had any probs, although I have a fan on them. Surely you have a fan somewhere that you can use, just to be safe