I did exactly what Zeff said and so far no problems that I couldn't fix. The rez sits outside of grow room and I use a 300w (if I remember right) aquarium heater to keep it warm when cold down there. I to live where they are only 2 seasons instead of 4, winter and construction seasons, so I know what ya mean when you say cold. I heat the inside of my room with a regular portable electric heater, just make sure you dont get one that has that orange "glow" to it when on. That would be classified as a light and no no in dark period.