I bulit a styrofaom incubator out of a styrofoam cooler. I used a 25 watt bulb through the top, wire mesh that sits about 2 inches off bottom, and vents holes. I am in day 12 and 12/12 eggs are coming along nicely. The way I control my temp, is by letting it run for a while, than checking the temp and if its too hot i make more holes, if its too cold i cover some up. With the holes it seems to stay at a even temp.