I have 9 seedlings growing in a box that is in an un-insulated room. The temperature in the box is around 60 degrees F with a new circulation fan I added (large PC fan), and a little bit higher without the fan running. The temperature in the box is too low, I know, and I want to increase it, because my 2.5 week old seedlings are growing really slowly. I currently have two 18 watt floro's, I'm thinking about getting higher wattage ones, will this increase the heat? And also, does having the temperature in the low 60's really slow growth down a lot? If I move up to say like 40 watt floro's will this help significantly? I don't want to go too high in watts, because A). I don't want to draw attention to the electricity bill, and B). I don't want to burn my plants. Thanks for any help.