I will turn on the lights in the bathroom when I get up and leave them on. In a hour or so they will have warmed the room a few degrees.

But this is a small, windowless, interior room.

I have used regular incandescent bulbs to keep water pipes from freezing too -- in small, enclosed, spaces. When younger I "toasted" bread over light bulbs.

We use flourescent bulbs and tubes where ever possible. In fact, any incandescent bulb we use is the exception (like in the bathrooms).