I bought a water base heater because of all the problems I was having with my heated waterer. I says it is good to 10*. What do you folks do in parts of the country that are well below 0 this time of year. I have read about the cookie tin heater but does that work at -10 or so? I haven't had much trouble in the past years as the sun shines in the window and warms things up quite well. This year so far the sun has been hiding. I have had to clean out ice a lot so far this year and am tired of it already. Looking for something to solve this problem. I went so far as to build a insulated house around the heated waterer with a opening for drinking. Still not good enough. Hoping my new heated base will solve the problem as soon as it gets here.