Longest-lasting Light Bulbs

Longest-lasting Light Bulbs

This is a list of the longest lasting incandescent light bulbs. Before the development of LED light bulbs, which have extremely long lifespans, incandescent bulbs that lasted more than a few years were quite uncommon and attracted significant media attention.

The world's longest lasting light bulb is the Centennial Light located at 4550 East Avenue, Livermore, California. It is maintained by the Livermore-Pleasanton Fire Department. The fire department claims that the bulb is at least 110 years old and has only been turned off a handful of times. The bulb has been noted by The Guinness Book of World Records, Ripley's Believe It or Not!, and General Electric as being the world's longest-lasting light bulb.

While it might seem astonishing that so many longest-lasting light bulbs have been so infrequently turned off, this is the precise reason for their longevity. Most of the wear and tear that leads to burnouts in incandescent light bulbs is caused by turning them on and off, not by burning them. Each time the bulb is turned on and off, the filament is heated and cooled. This causes the material of the filament to expand and contract, in turn causing tiny stress cracks to develop. The more the light is turned on and off, the larger these cracks grow, until eventually the filament breaks at some point, causing the light to burn out. Another reason for the longevity of bulbs is the size and quality of the filament.