Surface of the bulb when its on...335°F --10'' away from the front of the bulb, with no air circulation or a/c...approxitmately 95°F.

The back of the bulb, the reflective side, is always 95-98°F for me in my set up.
Quote Originally Posted by slowthestone
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The bulb's shape and ensuing physics of the heat that radiates from the bulb have that bit of really hot air rising up and cooling in a hurry...I have one fan, a bit more than 5' away, pointed right at the bulb, and another pulling the rising air above the lamp and dispersing it out of the area.

They'll fit in a cool tube too. I was going to go that route, decided though that a thin sheet of glass tween the lamp and the plants would suffice. A foot away from the lamp...the surface temp of the leaves is approx. 78°F. That though is with me running the fans and a/c. No doubt a cool tube would be better suited for corraling the heat than my method...albeit a lot more bulky and cumbersome which I can do without for the time.

When the current heat wave began sweating my room...I siwtched to growing at night...makes for a HUGE difference in the overall temp of the place during the photoperiod.