Terms of the Trade: What Is an Incandescent Bulb?

A grouping of light bulbs with one lit.

Whether you’re looking to simply replace a burnt out bulb or you’re attempting to increase your home’s energy efficiency, it can be confusing to know which light bulbs are best for your needs. Most of us are very familiar with incandescent bulbs, but they are being phased out for more efficient alternatives (such as the halogen variety).

Incandescent bulbs put off light when the wire filament inside is heated by electric current. However, they convert less than 5 percent of the energy they make into visible light, with the rest converted to heat. And compared to fluorescent bulbs which give off 60 lumens per watt, incandescent bulbs only give off 16 lumens per watt. But out of all the bulbs you see on the shelves, they remain the cheapest to manufacture and purchase.