How long did Thomas Edison’s first successful incandescent lamp reportedly burn?

Thomas Edison’s first successful incandescent lamp reportedly burned for about 13.5 hours.

The lamp used a carbonized filament sealed inside a glass bulb, with air removed to reduce combustion. Edison’s team tested many filament materials before achieving a practical, long-lasting design in 1879.

The roughly 13.5-hour result was an important improvement over earlier experimental lamps, but it was not the final performance standard. Edison continued refining the filament, vacuum, socket, wiring, and electrical distribution system.

The achievement was therefore a system of improvements rather than a single isolated bulb. Edison did not invent the first incandescent lamp, but he helped develop a commercially practical lighting system.