If it helps-I have 1 low energy(40 watts) one of those spirally things, outside of thier coop by the door so they can see food and water. The water dish is a 1 gal. heated dog dish which works real well. It helps scare away any pedators also. The temp here in Michigan has been in the single digits at night so I have a heat lamp in the coop, and they are laying 10-12 eggs per day. I sometimesforget to shut off the light, but it hasn't made a big dif in my elec. bill, maybe 2 or 3 dollars. Hope this helps