I also live in Iowa and I use an IR heat lamp at night (the light doesn't bother the girls). I bought a fountain heater from Theisen's for the water (the fountain sits on top of the heater). They are meant for metal fountains. They are thermostatically controlled. They are a little pricey, but worth the $45. My heat lamps are on a timer, but I am looking into a thermostatically controlled light socket that can handle 250 watts.