Why wait till it gets a certain degree of darkness before the nightlight comes on. This nightlight is always working and is super energy efficient. You will save money with this product. One of the best things about this product is that there are no bulbs to replace! How many times have you bought a nightlight, the bulb burns out, and when you go to the store, you have to figure out which bulb to buy. Then you realize that it costs about as much to just buy a new nightlight, so the old one goes in the trash. Not with the Electroluminescent Nightlight by GE!