Incandescent grow light, waste of money?

[OOAJ]

I know that most of the grow lights that are used are either flourescent or the high pressure sodium? bulbs, I was wondering if an incandescent bulb could be used as well. I ask because I'm a windowsill grower and as the days get shorter I was looking for something cost effective to provide a little extra light, rather than act as a primary source.

I picked up a 60 watt grow bulb at home depot and have it set up close to the plant with a timer. It definitely adds some extra warmth which is good, but I was wondering if the light it's producing was worth the electricity I'm burning.

Thanks in advance.