I got this with the 2 gallon double wall fount, as every morning I was having to change the water because it was frozen. I LOVE this thing. I'll be using it all this winter and then lovingly storing it till next year. One of the nicest things is that it doesn't heat the water all day, and the birds can't burn themselves, it just heat water that is getting below freezing, then it has an auto shut off. Really wonderful product, saves me time and energy in the morning and I don't have to worry that my girls don't have water. What clinched it for me was the days we have below 30, and the girls had no water all day, just ice to peck at. I felt terrible. So, no worry and no guilt. Love that!