Leslie, I have the type space heater that you described. I use it in the chicken coop because it's the safest form of heat that I can find for the chickens. It does have a thermostat on it and two heat settings. I don't remember what the settings are and it's out in the chicken coop and I'm not. Follow the safety precautions and you shouldn't have any problems with it. And no, electric heaters don't put of CO2.