Incandescent light bulbs makes its light by heating a metal filament wire to a high temperature until it glows. As a result, they are handy for heating rooms that are cold. They come in a variety of sizes and light output. They are gradually being replaced by fluorescent light bulbs.

Fluorescent light bulbs are energy saving, it has 17% higher luminous efficacy. Compared to incandescent light they give the same amount of visible light with less power and have a longer rated life, about 8 to15 times that of incandescent lights. However, they cost more than incandescent light, mostly about 3 to 10 times more costly. However fluorescent light produces less light later in their life than when they are new. You will observe that fluorescent light cast a gloomy, yellow glow. Fluorescent light contains mercury and this complicates disposal.