we insulated are metal water tank with the blue styrofoam insulation and built a plywood box around it with a lid, so the only part that is open is the side the horses are on, so they can stick their head in. Insulating makes a huge difference, on the power bill. Now I need to insulate a bigger round plastic one. And figure out how to keep the small water buckets from freezing so quick. it hasn`t been to terribly cold yet, but I have to smash ice and add hot water 2x a day, so they can drink... frustrating, and alot of work. We need to invent something better than whats already out there.