Cycles on and off with my furnace. I was able to just set it on the floor inside the return air duct on my furnace. Air that is returned from the house to the furnace to be reheated passes through the light. I made a base out of Styrofoam. All I needed to do was set it on the floor inside the furnace. I was able to very easily wire it to the furnace mother board so it cycles with the furnace. Some people say the bulbs last longer if you just leave it on all the time, but so far so good for me. I drilled a 1/2" hole in the side of the furnace duct and glued on the sawed off bottom of a green pill container. I can see if the light is on when the furnace is running though the green "sight glass".
Noah 
