Speaking from first hand experience...DON'T DO THAT!!!

I experimented with a UTH that was off a tank that was given to me. It was heck to get off, then it warped the steralite container, and emitted that wonderful burning plastic smell. I say experimented, because no one was living in the stearilite.

My advice? Human heating pads. Seventeen dollars at Walgreens for the non-shut off kind.