The wattage needed will depend on the environment temperature, insulation, and any air exchange. For a 30x18x36 inch grow tent in a garage and a desired printing temperature of 30°C, a 200 W ceramic heater will work for environment temperatures above 5°C. A 250 W heater is sufficient to -5°C, and a 500 W heater works in temperatures down to -35°C. Keep in mind that these are estimated values.