I have used the heated water for 2 winters also, unheated coop, we have not had much below zero temps. I also use the cookie tin with a 40wat bulb. both have their faults, 3 gal. heater is a pain to flip over withe out the bottom falling off, but I'm am getting pretty good at it. the water on the cookie tin gets pushed off occasionally so I built wood up around it so the water doesn't fall off so easily.