Incandescent bulbs fade to black

Thomas Edison’s pioneering incandescent light bulb, which cast illumination by heating a filament until it glowed, is fading into history.

New federal rules governing the energy efficiency of lighting systems went into full effect Tuesday, effectively ending the sale and manufacture of bulbs that trace their origin to an 1880 Edison patent.

The big winners are likely to be more efficient and longer-lasting LED bulbs. The rules don’t affect bulbs that you already own.

Only roughly 5% of the energy used by an incandescent bulb produces light; the remaining 95% or so is lost as heat. This is why you let an incandescent bulb cool off before unscrewing it.

They also burn out frequently, requiring replacement roughly every year.

AP/KNOX