Key Background An estimated 30% of U.S. households used incandescent or halogen incandescent light bulbs in 2020, according to the Department of Energy.

So, let's say the light bulb in your home appliance goes bad. It might be convenient to simply replace it with a spare regular bulb, but that's a big mistake most people make with light bulbs.

The English chemist Joseph Swan, Edison knew, was hard at work on a rival light bulb. Two Canadians, Henry Woodward and Mathew Evans, had already patented an inefficient design four years before.