If your house has any decent insulation that usually isn't a problem. If so get a space heater or a ceramic bulb. Since it's not truly known whether or not they can see the color red you should probably still avoid it in case they can. Light at night disturbs their sleep cycle, even if it isn't apparent to you, which could contribute to health issues down the line. I know I get sick much easier when I'm sleep deprived. They can sense light through a "third eye", a photosensitive scale cluster on the top of their heads. So even if you don't see them awake with a light on it doesn't mean it won't still affect them.