Quote:
Originally Posted by pdurrant
Halogens do run the filament at a higher temperature. And they do get hot, because they are so much smaller than normal incandescents. But for the amount of light they produce, they give off less heat than a normal incandescent. (Otherwise they wouldn't be more efficient, which they are, at the lamp.)
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According to the
Consumer Energy Center:
Quote:
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Unfortunately, these cheap and convenient halogen tubes waste energy by creating four times more heat than the average incandescent bulb. A 500-watt halogen reaches temperatures of over 1,200 degrees - creating a serious fire hazard. Curtains and other combustible materials can easily ignite if they get too close to the lamp.
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Halogens are considered
more efficient because they produce more light than an I-bulb for the same amount of power put into them. They will also last longer at the same light level as an I-bulb, and use less energy besides. (I almost specified "visible light," but of course, heat is the infra-red spectrum of light, and halogens put out more IR light for the same amount of power, too.) The amount of visible-vs-IR light emitted isn't really factored into their overall efficiency compared to other light sources, as far as I've been able to determine.
Halogens also have a significantly shorter lifespan at higher light levels, mainly thanks to that heat factor, so if you crank them up, you'll use the same amount of energy as an I-bulb and get more light, but you'll also be replacing them a lot more often.
Edit: Here's a good source of
further info on the "facts and myths" concerning halogens.