This is a pretty good thermostat for using a light bulb or even a low wattage heater:
Amazon.com : Farm Innovators Model TC-3 Cold Weather Thermo Cube Thermostatically Controlled Outlet - On at 35-Degrees/Off at 45-Degrees : Electrical Multi Outlets : Patio, Lawn & Garden
I used one for years to keep a pump house from freezing, no problem unless the light bulb burned out. I learned to use a two bulb system, with one bulb in a screw in light sensor, then if the first bulb did burn out, the second bulb would come on.
Amazon.com : Farm Innovators Model TC-3 Cold Weather Thermo Cube Thermostatically Controlled Outlet - On at 35-Degrees/Off at 45-Degrees : Electrical Multi Outlets : Patio, Lawn & Garden
I used one for years to keep a pump house from freezing, no problem unless the light bulb burned out. I learned to use a two bulb system, with one bulb in a screw in light sensor, then if the first bulb did burn out, the second bulb would come on.