Automotive v household lighting

SemiMan

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How is it that an H1 automotive bulb, introduced in 1962, outputs ~1550 lumens, but a "75-watt equivalent, 53-watt actual" household halogen incandescent bulb, only recently widely available (in the US, at least), outputs roughly one-half to two-thirds the amount of light?

http://en.wikipedia.org/wiki/H1_lamp

http://www.homedepot.com/p/Philips-...-24-Pack-226969/203267693?N=5yc1vZc8geZ2bcoqt


Anything near 30 lumens per watt for Halogen in HIR which is NOT a technology introduced in 1962. That said, automotive halogen is designed for a shorter life ... burns a bit hotter hence higher efficiency. Low voltage allows thicker filaments which again allows them to be driven a bit harder.

Semiman
 

Alaric Darconville

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How is it that an H1 automotive bulb, introduced in 1962, outputs ~1550 lumens, but a "75-watt equivalent, 53-watt actual" household halogen incandescent bulb, only recently widely available (in the US, at least), outputs roughly one-half to two-thirds the amount of light?

Anything near 30 lumens per watt for Halogen in HIR which is NOT a technology introduced in 1962. That said, automotive halogen is designed for a shorter life ... burns a bit hotter hence higher efficiency. Low voltage allows thicker filaments which again allows them to be driven a bit harder.

The H1 was introduced in 1962, and is nominally 55W, but at 13.2V, and 68w, it is 1550 ±15% lumens. This gives it a luminous efficacy from as high as 21.2lm/W to as low as 19.4lm/W. So, not 24-to-32lm/W as one would calculate from using the nominal 55W.

In the US, the H1 is rated 65w (maximum) and 1410 lumens ±15% at 12.8v.

Household halogen bulbs don't need the filament precision and beam focus that automotive halogen bulbs need, nor do they have the same filament luminance. That 53W household bulb will last quite a long time-- and that's one thing many consumers look for in a light bulb for the home.
 

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