On Sun, 29 Jul 2012 16:53:26 -0700, Jim Thompson
wrote:

Loony Question for Today...

Which produces more HEAT, a 40W Incandescent, or a 40W Halogen bulb?

An Incandescent will produce about 5 % of visible light, a halogen
about 7 %, the rest is heat as IR radiation and conducted heat. With
40 W electric input, the Incandescent will produce about 38 W heat,
while the halogen about 37 W of heat.