I use low wattage 60 or 40 watts.... either incandescent or cfl depending on what is available at the moment. I have them on timers. I just started turning them on about 2 wks ago and egg production jumped from 18 eggs to over 3 dozen a day... works everytime! I set them for 5 am to go off at 8am and then on again at 4pm until 7:30 pm