Quote Originally Posted by LIP
Yes, incandesant bulbs are your every day household bulbs, that produce NO lumens, and are the wrong psectrum, therefor rendering them useless.
Hey guys, thanks for the input.. It's helpin make this FAQ come along nicely.

I'd like to talk Incandescent

I found this in my CFL research, thought it'd shed some light on the incandescent issue.
""In a 120 volt, 100 watt "standard" bulb with a rated light output of 1750 lumens, the efficiency is 17.5 lumens per watt. This compares poorly to an "ideal" of 242.5 lumens per watt for one idealized type of white light, or 681 lumens per watt ideally for the yellowish-green wavelength of light that the human eye is most sensitive to.
Other types of incandescent light bulbs have different efficiencies, but all generally have efficiencies near or below 35 lumens per watt. Most household incandescent bulbs have efficiencies from 8 to 21 lumen per watt. Higher efficiencies near 35 lumens per watt are only achieved with photographic and projection lamps with very high filament temperatures and short lifetimes of a few hours to around 40 hours.
The reason for this poor efficiency is the fact that tungsten filaments radiate mostly infrared radiation at any temperature that they can withstand. An ideal thermal radiator produces visible light most efficiently at temperatures around 6300 Celsius (6600 Kelvin or 11,500 degrees Fahrenheit). Even at this high temperature, a lot of the radiation is either infrared or ultraviolet, and the theoretical luminous efficiency is 95 lumens per watt.""

So from this we see that Incandescent, like LIP says is almost useless. The percentage of useable lumen per watt ranges from 12 - 35lm/w Compared to practically any other type of lighting this is poor quality light. CFL's give us about 45-65 lumens per watt.
You can see there also the Overall Efficiency which makes it obvious that for 100watts it's really just not worth the heat and energy. However...It's still better than no light at all.

Incandescent than, should only be used as supplemental light...and that is if you have no other choice.