An hour here or there is no big deal if you have good lighting. If you have a compact fluorescent bulbs then you should probably keep it too a minimum or take him outside with you for some real UVB. Don't let him overheat outside.
I brought him outside for about an hour this morning to climb in the tree. He came back inside and wanted out again. So now he is climbing on my philodendron and peering out over the city lol. I was just wondering if he’s had too much for one day.