Quote:
Originally Posted by christofoo
Assuming 37kWhr/gal for gasoline: (EDITED)
'Eco' bulbs: reduction of 20W/15%(efficiency)/37,000Whr/gal = 0.015 gal/hr
HID (hypothetically): reduction of 0.03 gal/hr
|
So if you hypothesize that 'eco' halogens costs you $5 for one reason or another, the ROI is:
$5/(0.015gal/hr*$3.6/gal) = 90 hours of low-beam operation
Which is almost certainly within the lifetime of the bulb. (Or make it 200-300 hours if you throw away your old bulbs to put in new ones.)
So purely in economic terms, this type of bulb is probably worth using, even if you have no special purpose like an alt-delete or extensive after-dark engine-off time.
But clearly if there is no special purpose, this mod is about pinching pennies and splitting hairs. Although the electrical draw is easily measured, I'd expect the effect on fuel to be lost in the noise.